Harel–Yoon syndrome is caused by pathogenic variants in ATAD3A, a nuclear gene encoding a mitochondrial membrane protein central to cellular homeostasis. The gene regulates mitochondrial morphology, content, and turnover, processes that are especially critical in energy-hungry tissues such as brain, muscle, heart, and optic nerve. Since the original description of the syndrome in 2016, reported patients have ranged from infants with lethal neonatal encephalopathy and cardiomyopathy to longer-surviving children with hypotonia, spasticity, optic atrophy, and peripheral neuropathy. What has remained almost entirely unknown is the long-term trajectory: no previously published carrier of the p.Arg528Trp variant had ever been followed into adulthood.

The two sisters, aged 37 and 26 years, were born to first-cousin parents after uneventful pregnancies and normal perinatal periods. Their clinical course followed a familiar mitochondrial pattern. Patient 1 developed hypotonia at 12 months of age, with increased muscle tone and progressive spasticity evident by 3 years. Patient 2 began with hypotonia at 8 months, followed by spasticity from age 2 that ultimately progressed to loss of independent ambulation and permanent wheelchair dependence. Both women exhibited craniofacial dysmorphism, including gingival hypertrophy, a high forehead, mandibular protrusion, and low-set ears, along with optic atrophy confirmed by ophthalmological evaluation. Patient 1 also developed early cataracts.

Neurological examination revealed generalized spasticity, marked lower-limb hypotrophy, bradykinesia, and dysarthria in both patients. Patient 1 showed scanning dysarthria, whereas her sister displayed ataxic dysarthria, subtle differences that reflect the distribution of cerebellar and corticospinal involvement. Brain magnetic resonance imaging demonstrated mild diffuse cerebellar atrophy in both women, notably without supratentorial cortical atrophy, white matter abnormalities, basal ganglia involvement, or structural malformations. Electrophysiological studies showed a chronic sensorimotor polyneuropathy with axonal loss and conduction slowing affecting all four limbs. Electroencephalography revealed no epileptiform activity, echocardiography was unremarkable, and metabolic screening was entirely within normal limits.

The diagnostic journey illustrates the challenges posed by the ATAD3 locus. Clinical duo whole-exome sequencing performed in 2023 initially identified a variant of uncertain significance in COL5A1, a collagen gene associated with connective tissue disorders, along with a heterozygous pathogenic EPM2A variant that represented carrier status for an autosomal recessive condition and could not explain the neurological phenotype. Neither sister showed clinical features of a COL5A1-related disorder, such as skin hyperextensibility, abnormal scarring, or recurrent joint dislocations, so the collagen variant was interpreted as incidental. The known familial ATAD3A variant was not included among the exome findings, a discrepancy the authors describe as not reported rather than not detected, since locus-specific coverage data were unavailable for retrospective review.

Confirmation ultimately came through targeted single-site Sanger sequencing directed specifically at the ATAD3A NM_001170535.3:c.1582C>T variant. Genomic DNA extracted from peripheral blood was sequenced on a SeqStudio Genetic Analyzer, and the variant was confirmed in heterozygosity in both sisters. The authors reassessed pathogenicity using the ACMG/AMP framework, applying criteria for recurrent de novo occurrence, supportive functional evidence, extreme rarity in population databases, and concordant computational evidence. The p.Arg528Trp substitution has been reported as de novo in five unrelated affected individuals, and experimental studies in a Drosophila model demonstrated abnormal mitochondrial morphology, reduced mitochondrial content, and increased mitophagy, together with increased mitophagy in patient fibroblasts. ClinVar lists the variant as pathogenic or likely pathogenic with no conflicting submissions.

Reconciliation of the published literature identifies at least 12 unique individuals with the p.Arg528Trp variant before the present family. Most were children with severe neurodevelopmental disease and variable cardiac, metabolic, epileptic, sensory, or inflammatory involvement. The original Harel cohort described five patients evaluated between 23 months and 9 years of age, four of whom developed spasticity and peripheral neuropathy, three had optic atrophy, and two had hypertrophic cardiomyopathy. Additional patients reported by Lepelley and colleagues included a child with refractory seizures and no useful motor function, another with systemic sclerosis and gastrostomy-dependent feeding, and a third with respiratory-chain deficiency and cerebral lactate elevation. Later reports added infants with cardiac decompensation, metabolic crisis, and early-onset seizures.

What distinguishes the Colombian sisters is the coexistence of severe motor disability with relative cognitive preservation and limited systemic disease. Despite Barthel Index scores of 45/100 and 30/100, indicating moderate-to-severe and severe dependency in activities of daily living respectively, both women survived into adulthood, completed formal education, and achieved low-average IQ scores at single adult assessments. Neither had seizures, cardiomyopathy, lactate elevation, or other detected metabolic abnormalities. The authors emphasize that their phenotype is not globally mild but rather motor-severe while cognitively and systemically attenuated. Age is the most evidence-based explanation for the apparent difference in motor severity compared with pediatric reports, since decades of progressive spasticity and neuropathy could not be revealed by exclusively pediatric follow-up. Age does not, however, explain the comparatively mild cognitive involvement or the absence of cardiac and metabolic abnormalities.

The recurrence of the variant in two sisters requires cautious genetic interpretation. Parental segregation could not be assessed because their father died before genetic evaluation and their mother declined further clinical evaluation and targeted segregation testing. Parental germline or low-level somatic mosaicism remains a plausible explanation for recurrence, but inherited transmission cannot be distinguished without parental data. The extensive homology among ATAD3A, ATAD3B, and ATAD3C also limits conventional short-read detection of copy-number changes and complex rearrangements within the locus. The authors note that targeted copy-number analysis and long-read sequencing in the sisters would help exclude additional contributors, although they would not resolve inheritance without parental samples.

No disease-modifying treatment is established for Harel–Yoon syndrome, and management remains supportive. In these patients, botulinum toxin injections for spasticity, combined with ongoing physical and multidisciplinary rehabilitation, improved passive limb mobilization and facilitated basic caregiving activities including hygiene and positioning, but did not alter disease progression. The authors highlight the importance of comprehensive genetic evaluation in suspected mitochondrial disorders and emphasize that adult survival and relative cognitive preservation do not imply limited neurological severity. These observations carry implications for prognosis, genetic counseling, and clinical management, and they underscore the value of long-term follow-up and patient-level comparison without duplicate counting in the study of rare mitochondrial diseases.

Subject of Research: Case report: Harel–Yoon syndrome (ATAD3A p.Arg528Trp) with relative cognitive preservation despite severe motor impairment

Article Title: Case report: Harel–Yoon syndrome (ATAD3A p.Arg528Trp) with relative cognitive preservation despite severe motor impairment

Article References: Zamudio Soledad, P. N., Montoya, J. S., Poveda-Rodriguez, D. S., King Chio Cho, L. M., Reyes, M. A., & Bernal Pacheco, O. (2026). Case report: Harel–Yoon syndrome (ATAD3A p.Arg528Trp) with relative cognitive preservation despite severe motor impairment. Frontiers in Genetics, 17, Article 1881863. https://doi.org/10.3389/fgene.2026.1881863

Image Credits: AI Generated

DOI: 10.3389/fgene.2026.1881863

Keywords: Case, report, Harel, Yoon, syndrome, ATAD3A, Arg528Trp, relative, cognitive, preservation, despite, severe

The study focused on three specific species: Hemiandrus electra, Hemiandrus nox, and an undescribed species referred to as Hemiandrus ‘disparalis’. These insects are members of the family Anostostomatidae, a group known for its diversity in New Zealand. While all three species are nocturnal and use soil burrows for shelter during the day, their dietary preferences vary markedly. The researchers examined the crop contents of 66 adult specimens, carefully extracting and analyzing food fragments under a stereomicroscope. The results revealed that H. electra and H. ‘disparalis’ are predominantly herbivorous, with less than 20% of their diet consisting of invertebrate fragments. In stark contrast, H. nox is primarily carnivorous, with approximately 80% of its crop contents identified as animal remains, including insect exoskeletons, antennae, and mandibles.

This dietary divergence suggests a form of resource partitioning, a common ecological strategy that allows multiple species to coexist by reducing direct competition for food. The plant fragments found in the crops of the herbivorous species indicated a polyphagous diet, with evidence of both dicot and monocot plant tissues. For H. nox, the presence of plant matter, though minor, may be incidental, resulting from the consumption of prey that had recently fed on vegetation. The study also noted that there were no significant differences in diet between males and females of any of the three species, a finding that contrasts with some previous studies on other weta species. This suggests that both sexes have similar nutritional requirements or that the coarse level of dietary analysis used in this study did not capture subtle sex-specific variations.

Relative abundance and sex ratios provided further insights into the population dynamics of these weta. A total of 966 specimens were identified from malaise traps set in the St Arnaud forest. H. electra was the most abundant species, accounting for 701 individuals, followed by H. ‘disparalis’ with 157 and H. nox with 109. This pattern aligns with general ecological principles, where species at higher trophic levels, such as the carnivorous H. nox, tend to be less abundant than their herbivorous counterparts. However, the researchers caution that trap interception may reflect behavioral differences, such as climbing activity, rather than true population sizes. The sex ratios were particularly intriguing. While H. ‘disparalis’ and H. nox showed a strong male bias in the traps, with males outnumbering females by more than two to one, H. electra exhibited a nearly even sex ratio of 355 males to 346 females.

The even sex ratio in H. electra is surprising because this species is known for maternal care, a behavior where females remain in their burrows to guard eggs and nymphs. One might expect that females would be less active and therefore less likely to be caught in traps, leading to a male-biased sample. The fact that H. electra females were caught in equal numbers to males suggests that their activity levels, at least during the sampling period, were comparable to those of males. This finding challenges previous assumptions about the behavioral consequences of maternal care in weta and highlights the need for further research into the daily activity patterns of these insects. The other two species, lacking maternal care, showed the expected male bias, possibly because males are more active in searching for mates and food after the mating season.

Another key aspect of the study was the analysis of growth and development in H. electra, the most abundant species. Using hind leg dimensions as a proxy for body size, researchers applied Gaussian mixture models to classify female specimens into five distinct size clusters. These clusters likely correspond to different developmental stages, or instars, with cluster 5 representing adults and cluster 1 representing the smallest nymphs. The distribution of these size classes across the sampling months revealed no clear seasonality in growth. Almost all size classes were present in each month, indicating that H. electra does not synchronize its development with specific seasons. This continuous growth pattern is unusual for many insects, which often have distinct reproductive cycles tied to seasonal changes in temperature and resource availability.

The absence of seasonality in H. electra suggests that the temperate rainforest environment provides a relatively stable set of conditions that support continuous development. While the smallest nymphs were absent in November, December, and April, the presence of all other size classes throughout the year indicates a multivoltine life cycle, where multiple generations can overlap. This finding has implications for understanding the population dynamics of weta in New Zealand’s forests, as it suggests that these insects are not constrained by seasonal bottlenecks in their life cycle. The study also highlights the importance of long-term monitoring programs, such as the Vespula wasp management program from which the weta specimens were collected, in providing valuable data on the ecology of non-target species.

The ecological significance of these findings extends beyond basic biology. Some weta species are considered pests in agricultural settings, particularly in vineyards and orchards. Understanding the natural diet and behavior of wild populations can inform integrated pest management strategies. For instance, knowing that H. electra and H. ‘disparalis’ are primarily herbivorous and feed on a variety of plant species can help identify which crops or plants are most vulnerable to weta damage. Conversely, the carnivorous nature of H. nox suggests that it may play a role in controlling populations of smaller invertebrates in the forest ecosystem. These insights can contribute to more nuanced approaches to managing weta populations in both natural and modified habitats.

Despite the valuable insights provided by this study, several questions remain unanswered. The exact mechanisms driving the dietary differences among the three species are not fully understood. While resource partitioning is a plausible explanation, other factors, such as phylogenetic constraints or historical ecological pressures, may also play a role. Additionally, the study did not investigate the diet of different instars, which could reveal further variations in feeding behavior. Future research should focus on long-term monitoring of weta populations, incorporating more detailed dietary analyses and behavioral observations. By studying these insects in their natural habitats, rather than extrapolating from related taxa, researchers can gain a more accurate understanding of their ecology and evolution. This study serves as a foundation for such future work, highlighting the rich diversity and complexity of New Zealand’s orthopteran fauna.

Subject of Research: Comparison of growth, relative abundance, and diet of three sympatric Hemiandrus ground wētā (Orthoptera, Anostostomatidae) in a New Zealand Forest

Article Title: Comparison of growth, relative abundance, and diet of three sympatric Hemiandrus ground wētā ( Orthoptera , Anostostomatidae ) in a New Zealand Forest

Article References: Chikwature, N., Morgan-Richards, M., Vereijssen, J., & Trewick, S. A. (2025). Comparison of growth, relative abundance, and diet of three sympatric Hemiandrus ground wētā (Orthoptera, Anostostomatidae) in a New Zealand Forest. Journal of Orthoptera Research, 34(1), 1-10. https://doi.org/10.3897/jor.34.123860

Image Credits: AI Generated

DOI: 10.3897/jor.34.123860

Keywords: Comparison, growth, relative, abundance, diet, three, sympatric, Hemiandrus, ground, Orthoptera, Anostostomatidae, Zealand

The biological logic begins with the Sertoli cell, the somatic nurse cell of the seminiferous epithelium. Sertoli cells provide the structural scaffold, metabolic substrates, and paracrine signals that developing germ cells require, and they orchestrate the apoptotic elimination and phagocytic clearance of defective cells before sperm release. During spermiogenesis, the final phase of sperm construction, histones are replaced first by transition proteins and then by protamines, a chromatin remodeling process accompanied by transient physiological DNA breaks that are normally repaired before final condensation. Experimental studies show that Sertoli cells suppress apoptotic DNA fragmentation in pachytene spermatocytes and round spermatids through paracrine and cell-contact-dependent mechanisms. If Sertoli-cell support weakens, under-protaminated chromatin, incomplete DNA repair, and the persistence of damaged germ cells could theoretically follow, allowing sperm with abnormal packaging or unresolved breaks to reach the ejaculate.

FSH is the key endocrine regulator of this support system. It acts through the FSH receptor, a seven-transmembrane G protein-coupled receptor expressed exclusively on Sertoli cells, triggering the canonical cAMP/PKA pathway alongside context-dependent ERK/MAPK and PI3K/Akt/mTOR cascades. These coordinated pathways regulate Sertoli-cell metabolic activity, junctional dynamics, glucose uptake, glycolysis, and lactate production, the last being critical because developing spermatids depend substantially on Sertoli-cell-derived lactate. Strikingly, experimental work shows that conditional deletion of the lactate dehydrogenase gene Ldha in Sertoli cells altered more than 2,400 metabolites in sperm and produced profound defects in spermiogenesis. FSH withdrawal, meanwhile, increased DNA fragmentation in primary spermatocytes and spermatids in cultured human seminiferous tubules, providing direct mechanistic support for the idea that FSH-dependent signaling helps maintain germ-cell DNA integrity.

The central insight of the review, however, is that circulating FSH concentrations may not accurately reflect effective intratesticular FSH action. Inter-individual variation in FSH receptor expression, receptor polymorphisms, ligand-receptor interactions, receptor trafficking, and downstream signaling efficiency may all influence the biological response to an equivalent serum FSH level. Clinical data indicate that some idiopathic infertile men have reduced testicular volume and sperm counts despite subnormal to normal serum FSH, suggesting that the hormone measured in blood is a marker of endocrine stimulation rather than a direct measure of biological action at the Sertoli-cell level. The review therefore defines relative Sertoli-cell FSH hyporesponsiveness as a functional phenotype of reduced effective FSH signaling, irrespective of whether the defect resides in ligand bioactivity, receptor biology, or downstream intracellular competence. Some men with normal or near-normal FSH may nevertheless exhibit this state.

The strongest direct clinical evidence comes from pharmacogenetic trials of recombinant FSH therapy. In a multicenter prospective study, Simoni and colleagues demonstrated that recombinant FSH reduced the DNA fragmentation index in idiopathic infertile men depending on the FSHR p.N680S genotype, with a significant reduction seen only in homozygous N carriers. Other trials have reported mean DFI reductions of roughly 20 to 50 percent after three months of treatment, although these studies differ markedly in patient selection, baseline gonadotropin levels, FSH preparation, dose, duration, and SDF assay. A pooled analysis of individual patient data found that higher post-treatment testosterone and younger age were associated with greater DFI improvement. Collectively, these findings support the biological plausibility of a relationship between FSH signaling and sperm DNA integrity, but they do not establish that relative hyporesponsiveness is the underlying cause of elevated SDF.

Associative human evidence adds indirect support. Common variants in the FSHB and FSHR genes, including the FSHB promoter −211G>T variant and FSHR variants such as −29G>A, Thr307Ala, and Asn680Ser, have been associated with modest differences in serum FSH, inhibin B, and testicular volume, with less consistent associations for sperm concentration. These polymorphisms appear to modify testicular responsiveness to FSH and may explain why some men with low-normal FSH levels exhibit impaired spermatogenesis. Endocrine biomarkers such as inhibin B and anti-Müllerian hormone correlate with spermatogenic output and provide indirect information about Sertoli-cell function, but they are neither specific indicators of SDF nor direct measures of effective FSH responsiveness. The genotype-phenotype associations remain modest, not consistently replicated across populations, and do not establish causality.

To translate this hypothesis into testable research, the review proposes the FERTILE framework, a seven-domain conceptual model integrating FSH and effective intratesticular signaling, endocrine markers including inhibin B, AMH, and testosterone, receptor and ligand genetics, testicular structure, inflammation and oxidative stress, lifestyle and environmental factors, and evaluation of DNA integrity using standardized assays. The framework is explicitly qualitative, intended for biological stratification and hypothesis generation rather than clinical decision-making. It acknowledges that SDF assays, including TUNEL, SCSA, SCD, and the comet assay, measure overlapping but non-identical aspects of DNA damage and generate non-comparable numerical values, a methodological obstacle that remains one of the major barriers to standardization in both research and clinical practice.

The review is careful to situate the hypothesis within the broader multifactorial pathophysiology of SDF. Varicocele, characterized by dilated veins of the pampiniform plexus, promotes testicular hyperthermia, oxidative stress, hypoxia, and impaired Sertoli-cell function, and meta-analyses of varicocelectomy consistently demonstrate significant postoperative reductions in SDF, with weighted mean differences of roughly −6 percent at three months and greater reductions at six months. Oxidative stress from smoking, obesity, infection, and environmental toxicants induces DNA strand breaks, oxidative base modifications, and chromatin cross-linking, and a prospective study of 105 obese men found that a 12-week lifestyle intervention reduced mean DFI from 20.2 to 17.5 percent. The Global Andrology Forum 2026 guidelines on antioxidant use emphasize that a complete clinical and andrological evaluation should precede therapy and warn against indiscriminate or prolonged antioxidant use. Established causes should be identified and managed before considering additional hypothesis-driven mechanisms.

The review also outlines how the hypothesis could be falsified. It would be considered unsupported if prospectively stratified randomized trials demonstrate that recombinant FSH does not improve SDF or chromatin packaging in predefined pharmacogenetic subgroups, if in vitro models show that blocking downstream FSHR signaling cascades does not affect protamine incorporation or DNA integrity, or if in vivo studies demonstrate that variation in FSHR signaling efficiency does not correlate with markers of Sertoli-cell support or germ-cell survival. Validation would require assessment of FSH receptor abundance, localization, ligand-induced signaling activity, and downstream phospho-signaling responses in Sertoli cells from men with and without elevated SDF, correlated with standardized SDF assays, chromatin-packaging markers, endocrine profiles, genotype, and reproductive outcomes. Such comprehensive datasets are currently unavailable.

The proposed model may ultimately explain why some men with apparently preserved endocrine profiles and conventional semen parameters nevertheless exhibit elevated SDF and impaired reproductive outcomes. A recent meta-analysis including more than 12,000 IVF and ICSI cycles reported that elevated SDF was associated with reduced implantation and pregnancy rates, particularly in conventional IVF, and showed a detrimental trend for live birth. If future studies demonstrate that relative Sertoli-cell FSH hyporesponsiveness contributes to persistent sperm DNA damage, biologically targeted interventions could potentially improve semen quality and reproductive outcomes in appropriately selected patients. Until such evidence becomes available, the FERTILE framework and the concept of relative Sertoli-cell FSH hyporesponsiveness should be regarded as hypothesis-generating research tools intended to facilitate biological stratification and future translational investigation rather than as a basis for changing routine evidence-based clinical practice.

Subject of Research: Reproductive Biology

Article Title: Relative Sertoli-cell FSH hyporesponsiveness as a potential contributor to sperm DNA fragmentation: a hypothesis-driven narrative review and proposal of the FERTILE framework

Article References: Kandil, H. (2026). Relative Sertoli-cell FSH hyporesponsiveness as a potential contributor to sperm DNA fragmentation: a hypothesis-driven narrative review and proposal of the FERTILE framework. Frontiers in Urology, 6, Article 1915445. https://doi.org/10.3389/fruro.2026.1915445

Image Credits: AI Generated

DOI: 10.3389/fruro.2026.1915445

Keywords: sperm DNA fragmentation, FSH, Sertoli cells, male infertility, FERTILE framework, pharmacogenetics, reproductive endocrinology, Relative, Sertoli-cell, hyporesponsiveness, potential, contributor

The research team, working in the Susa Valley in Piedmont at elevations of 800 to 900 meters, collected 88 adult dung beetles from cow dung in May, spanning nine species, four tribes, and all three major nesting strategies known from mid-altitude Alpine pastures. The species included dwellers such as Aphodius pedellus and Colobopterus erraticus, which lay their eggs within the dung mass; tunnellers such as Anoplotrupes stercorosus, Geotrupes mutator, Trypocopris pyrenaeus, and three Onthophagus species, which bury brood balls in tunnels beneath the dung; and a single roller, Sisyphus schaefferi, which shapes dung into a ball and rolls it away for burial. By sourcing every individual from the same dung, deposited by a herd of Piedmontese cattle, the researchers minimised dietary variation, ensuring that any differences in gut microbiota could be attributed to the host rather than the meal.

To characterise the microbial communities, the team employed an amplicon sequence variant (ASV)-based metabarcoding approach, a technique that offers higher taxonomic resolution and reproducibility than traditional operational taxonomic units. For prokaryotes, the 16S ribosomal RNA gene was amplified using the primer set 515fB and 806rB, while for fungi, the internal transcribed spacer 2 (ITS2) region was targeted through a semi-nested PCR protocol. Sequencing was performed on an Illumina NovaSeq platform, generating paired-end reads of 250 base pairs. Bioinformatic processing in QIIME2, with denoising and chimera removal handled by the DADA2 plugin, yielded 12,501 prokaryotic ASVs and 3,301 fungal ASVs. Taxonomic assignment drew on the Greengenes2 database for prokaryotes and the UNITE database for fungi. Environmental ASVs shared between beetles and dung or soil samples were removed before diversity analyses to isolate the gut-associated fraction of the microbiota.

The results revealed a fundamental asymmetry between the prokaryotic and fungal components of the gut microbiota. Prokaryotic communities exhibited strong host-dependent structuring: distance-based redundancy analysis (dbRDA) of Bray-Curtis dissimilarities showed that the nine beetle species separated into four non-overlapping clusters corresponding precisely to their four tribes. Species identity explained 88.1 percent of the variation in prokaryotic community composition, followed by tribe at 79.7 percent and nesting strategy at 44.7 percent, all highly significant. Sex, by contrast, accounted for a negligible and non-significant 2.74 percent. This pattern is consistent with phylosymbiosis, the phenomenon whereby host phylogeny structures associated microbial communities through evolutionary filtering and partially conserved symbiotic associations.

Fungal communities told a very different story. The dbRDA ordination showed extensive overlap among seven of the nine species, with only Aphodius pedellus and Anoplotrupes stercorosus forming distinct clusters. Species explained 80.6 percent of the variation, but tribe accounted for just 26.4 percent and nesting strategy 23.2 percent, suggesting that fungal assemblages are weakly constrained by host evolutionary history. The researchers attribute this to greater environmental acquisition: dung beetles continuously ingest microbially rich dung and soil, and fungal propagules from these substrates likely colonise the gut more transiently than bacteria, which appear to form more stable mutualistic associations.

The analysis of exclusive and core ASVs reinforced this asymmetry. Exclusive prokaryotic ASVs, unique to individual beetle species, numbered 10,677 of the 12,501 detected, representing 85.4 percent of all ASVs but only 21.3 percent of total reads. Exclusive fungal ASVs comprised 83.6 percent of detected taxa but only 34.1 percent of reads. Most species-exclusive ASVs were detected in a single individual, casting doubt on their biological exclusivity and highlighting the importance of sampling at least eight to ten individuals per species. In contrast, the core microbiota shared across all nine species was numerically scarce, with only 47 prokaryotic and nine fungal ASVs, yet these accounted for a disproportionate 19.5 percent of prokaryotic and 5.7 percent of fungal read abundance. The most abundant prokaryotic core genera included Vagococcus_B, Apibacter, and Acinetobacter, while over half of the fungal core ASVs belonged to the genus Candida.

At the genus level, the prokaryotic communities were dominated by Proteobacteria, Firmicutes_D, and Bacteroidota, which together accounted for roughly 80 percent of ASVs. The three most abundant genera across all samples were Wolbachia, Apibacter, and Vagococcus_B, but their relative contributions varied markedly among host species. Apibacter dominated the microbiota of two Onthophagus species at approximately 30 percent, Wolbachia reached 24 percent in Onthophagus verticicornis, Enterococcus_G contributed a quarter of the community in Trypocopris pyrenaeus, and Vagococcus_B peaked at 16 percent in both Geotrupes mutator and Trypocopris pyrenaeus. When species were grouped by tribe, clear tribal signatures emerged: Aphodiini showed the highest abundance of Acinetobacter, Onthophagini the highest Apibacter, and Geotrupini the highest Enterococcus_G and Vagococcus_B. Among fungi, Ascomycota and Basidiomycota accounted for 95 percent of ASVs, with Apiotrichum, Epicoccum, and an unclassified Agaricomycetes genus most abundant overall. Apiotrichum represented 38 percent of the fungal community in Geotrupes mutator, Trichosporon reached 32 percent in Sisyphus schaefferi, and Candida was found almost exclusively in Anoplotrupes stercorosus at 35 percent.

Despite this pronounced taxonomic turnover, the predicted functional profiles remained remarkably consistent across hosts. Among prokaryotes, fermentation was the predominant metabolic process, averaging 28 percent of the functional profile, while nitrogen-related pathways, including nitrate reduction, nitrate respiration, nitrite denitrification, nitrogen fixation, and ureolysis, contributed nearly one quarter and were relatively constant among species. Fungal communities were largely saprotrophic, accounting for approximately 46 percent of the trophic distribution, followed by pathotrophy at 35 percent and symbiotrophy at 19 percent. Wood saprotrophs dominated the saprotrophic guild at 15 percent, with soil, litter, and dung-associated saprotrophs present at lower abundances. These proportions were largely consistent across species, with only minor deviations in a few hosts.

This decoupling between taxonomic composition and functional potential is the study’s central finding and points to substantial functional redundancy in the dung beetle gut microbiota. The concept, well established in microbial ecology, holds that different microbial consortia assembled from different taxonomic pools can nonetheless maintain similar functional outcomes. The researchers suggest this redundancy may reflect two evolutionary pressures: the need to preserve host health and the need to sustain efficient dung degradation and nutrient cycling. Even if the composition of the gut microbiota changes dramatically, as might occur when pastoral practices shift or dung beetle communities restructure in response to land abandonment and climate change, the microbial functions underpinning dung transformation are likely to remain stable.

The implications extend beyond basic microbiome science. Pastoral ecosystems in the European Alps are undergoing rapid transformation, with grasslands giving way to woody encroachment and forest expansion driven by land abandonment and warming temperatures. The widespread reduction in extensive livestock systems further threatens dung-dependent communities. Understanding that dung beetle gut microbiota are resilient systems, capable of maintaining key metabolic roles under changing taxonomic compositions, offers a measure of reassurance about the continuity of the ecosystem services these insects provide. The authors caution, however, that the functional profiles were predicted rather than measured experimentally, and that future work integrating metagenomics or metatranscriptomics, together with experimental manipulation of diet and microbiota, will be essential to clarify the functional significance of specific microbial taxa and disentangle the relative contributions of host filtering and environmental acquisition in shaping these remarkable gut ecosystems.

Subject of Research: Gut microbiota of dung beetles shows taxonomic turnover but relative functional stability

Article Title: Gut microbiota of dung beetles shows taxonomic turnover but relative functional stability

Article References: Natta, G., Voyron, S., Lumini, E., Laini, A., Roggero, A., Palestrini, C., & Rolando, A. (2026). Gut microbiota of dung beetles shows taxonomic turnover but relative functional stability. Metabarcoding and Metagenomics, 10, Article e194720. https://doi.org/10.3897/mbmg.10.194720

Image Credits: AI Generated

DOI: 10.3897/mbmg.10.194720

Keywords: microbiota, dung, beetles, shows, taxonomic, turnover, relative, functional, stability, scientific research

The research team assembled a mixed sample of 955 participants drawn from Iran, combining 143 psychiatric patients who met DSM-5 criteria for somatic symptom and related disorders (SSRD) with 812 individuals from the general population who did not carry that diagnosis. The sample had an average age of 34.2 years, with a standard deviation of 11.5 years, and was 66 percent female. This design deliberately blended a clinically severe group with community participants, allowing the investigators to examine how somatization relates to other forms of psychopathology across a wide spectrum of severity rather than only within a narrow patient population.

Methodologically, the study took what the authors describe as a multidimensional approach. Participants completed a battery of self-report questionnaires covering somatic symptoms, psychological syndromes such as depression and anxiety, and two distinct ways of characterizing personality pathology. The first, criterion-based approach reflects the traditional categorical diagnosis of personality disorder, in which individuals are judged against diagnostic checklists. The second, trait-based approach follows the newer dimensional model, assessing maladaptive personality traits as continuous dimensions. By including both frameworks, the researchers could test whether the answer to their question depended on how personality pathology is defined — a critical check, because the field of personality assessment is currently in transition between these two paradigms.

To reduce the many questionnaire items to interpretable constructs, the team used exploratory factor analysis, a statistical technique that identifies clusters of variables that covary together and can be treated as underlying latent dimensions. This procedure extracted four factors corresponding to somatization, psychological syndromes, criterion-based personality disorder, and maladaptive trait-based personality pathology. In other words, the data themselves organized into the conceptual categories the researchers set out to compare, providing a clean foundation for the predictive analyses that followed.

The heart of the study lay in hierarchical linear regression, a technique that allows researchers to enter predictors in stages and measure how much additional variance each block explains. Here the logic was straightforward but powerful: if somatization were fundamentally a manifestation of personality pathology, then personality measures should explain substantial variance in somatic symptom reporting even after current psychological distress is statistically controlled. Conversely, if somatization is chiefly tied to present distress, the psychological syndromes factor should dominate. The results were unambiguous, and the effect sizes were striking.

Compared with criterion-based personality disorder, the psychological syndromes factor was far more strongly related to the somatization factor. The psychological syndromes accounted for an R-squared of 0.512, meaning they explained just over half of the variance in somatization scores, whereas criterion-based personality pathology explained only 0.105. In the hierarchical models, the incremental contribution — the change in R-squared — was 0.414 for psychological syndromes against a mere 0.007 for criterion-based personality disorder. The same pattern emerged when the trait-based model was used instead: psychological syndromes achieved an R-squared of 0.512 versus 0.138 for maladaptive traits, with incremental values of 0.377 versus 0.004. Whichever lens was applied to personality, the conclusion held.

The team also examined a single-item, pain-related measure as a separate outcome, and here too psychological syndromes outperformed both personality frameworks, though with smaller absolute effects. The syndromes factor explained an R-squared of 0.151 for the pain measure, compared with 0.067 for criterion-based personality disorder and 0.066 for trait-based pathology. The incremental contributions were 0.086 for psychological syndromes against 0.003 and 0.001 for the two personality approaches respectively. The authors are careful to note that these pain findings rest on a single-item indicator and should not be generalized to multidimensional assessments or to chronic pain conditions, where the underlying dynamics may differ considerably.

What do these numbers mean conceptually? The authors conclude that somatization appears to be a phenomenon primarily related to psychological distress rather than to personality pathology, and that this holds regardless of the theoretical context used to define personality problems. This does not mean personality pathology is irrelevant. The study found that both criterion-based and trait-based personality pathology were independently related to somatization, so the association is real. But when current psychological distress is taken into account, personality pathology shrinks to a marginal predictor. In practical terms, a patient’s present levels of depression, anxiety, and related syndromes carry most of the predictive signal for bodily symptom reporting, while personality structure adds only a thin residual layer of explanation.

The clinical implications are significant. Somatization is notoriously difficult to treat, and patients with somatic symptom and related disorders often consume substantial health care resources through repeated investigations and specialist referrals that yield little relief. If the strongest statistical lever for understanding somatization is current psychological distress rather than entrenched personality pathology, then interventions targeting distress — such as treatments for depression and anxiety — may offer the most direct route to reducing the burden of somatic symptoms. The authors explicitly frame their findings as a way to refine theoretical models and improve clinical outcomes by targeting the most impactful constructs, and the variance figures suggest that distress-focused constructs are precisely those impactful targets.

The study also carries methodological lessons for the research community. Because the pattern of results was consistent across both categorical and dimensional conceptualizations of personality pathology, the conclusion is not an artifact of one diagnostic school. The use of factor analysis to establish latent dimensions before regression, and the hierarchical entry of predictors to isolate incremental validity, provide a template for similar comparative questions in psychopathology research. The work was approved by the ethics committee of the Mind GPS Institute of Kermanshah, Iran, conducted in accordance with the Helsinki Declaration, and supported methodologically by that institute without external funding. As with any cross-sectional, self-report study, causal direction cannot be established, and the general-population sample from a single country invites replication elsewhere. Yet the sheer size of the gap — psychological syndromes explaining roughly half the variance in somatization while personality pathology explains a tenth or less — makes this one of the clearer statistical verdicts the field has received on a long-standing debate, and it points clinicians firmly toward treating the distress, not just the personality, when the body speaks for the mind.

Subject of Research: The relative contribution of psychological syndromes and personality pathology to somatization

Article Title: Relative sensitivity of phenotypic personality pathology and psychological syndromes to somatization phenomenon: a multidimensional approach

Article References: Komasi, S., Macina, C., Miettunen, J., Nazari, A., Heydarpour, B., Shams-Alizadeh, N., & Amianto, F. (2026). Relative sensitivity of phenotypic personality pathology and psychological syndromes to somatization phenomenon: a multidimensional approach. Discover Mental Health. https://doi.org/10.1007/s44192-026-00615-0

Image Credits: AI Generated

DOI: 10.1007/s44192-026-00615-0

Keywords: somatization, somatic symptom and related disorders, personality pathology, psychological distress, DSM-5, hierarchical regression, factor analysis, maladaptive traits, pain, psychopathology, mental health, Relative