The study used array comparative genomic hybridization and SNP-array records generated with two platforms over the study period. All software calls were manually reviewed, and potential findings were retained when they were at least 100 kilobases, involved at least 20 consecutive probes, or overlapped a known disease-associated gene or recurrent region. The researchers then re-curated all records against a single April 28, 2026 ClinGen release and converted earlier GRCh37 coordinates to GRCh38. This approach was designed to avoid counting partial overlaps, terminal abnormalities, complex rearrangements or unusually sized events as canonical recurrent CNVs merely because they touched a recognized locus.

To assign a recurrent region, investigators required agreement between the array-defined breakpoints and the flanking low-copy repeat blocks, together with a size compatible with the canonical interval. Minor endpoint differences were accepted when they were consistent with the same established region, but a percentage-overlap threshold was not used. Classification was a separate step: deletions were evaluated against region-specific haploinsufficiency evidence and duplications against triplosensitivity evidence under the 2019 ACMG/ClinGen standards. This distinction was central to the results, because recurrence describes how a copy-number change arises, whereas pathogenicity depends on its exact region, dosage direction and supporting evidence.

Overall, a pathogenic or likely pathogenic copy-number finding was identified in 278 of 1,661 postnatal probands, or 16.74%, and in 28 of 401 prenatal samples, or 6.98%. The study identified 109 recurrent-CNV carriers, including one postnatal proband with two independent recurrent events. Among the 92 postnatal carriers, 66 had pathogenic or likely pathogenic recurrent CNVs, representing 23.74% of all postnatal pathogenic copy-number findings. Seven of 17 prenatal carriers had pathogenic recurrent CNVs, accounting for 25.00% of prenatal pathogenic findings. The remaining recurrent events were classified as variants of uncertain significance or benign rather than being treated as diagnostically equivalent to pathogenic events.

The regional distribution varied between the two clinical settings. Proximal 22q11.21 deletions, associated with DiGeorge or velocardiofacial syndrome, and proximal 16p11.2 CNVs were the most frequent postnatal findings. Other recurrent entities included Xp22.31, proximal 7q11.23, 17q12 and 15q11.2–q13.1. Deletions predominated after birth, accounting for 64 of 93 postnatal recurrent-CNV events, or 68.82%. By contrast, duplications accounted for 11 of 17 prenatal events, or 64.71%. The prenatal pathogenic fraction was correspondingly lower, underscoring that the dosage direction of a recurrent CNV cannot be inferred from the region label alone.

Test purpose strongly influenced the observed yield among postnatal probands. Pathogenic recurrent CNVs were found in six of 19 cases tested because a specific recurrent-CNV syndrome was suspected, a yield of 31.58%, although this small subgroup had a wide 95% confidence interval of 15.36% to 53.99%. Among 1,589 phenotype-driven diagnostic tests without prior suspicion of a particular recurrent syndrome, 58 carried a pathogenic recurrent CNV, giving a yield of 3.65%. The targeted group produced the higher proportion, but phenotype-driven testing contributed 58 of the 66 postnatal pathogenic recurrent-CNV carriers. Neurodevelopmental and neurological referrals were the largest postnatal referral category and accounted for 38 of those 66 carriers.

Most fetal samples were referred because of an ultrasound abnormality, which was the primary indication in 348 of 401 cases, or 86.78%. Within this subgroup, 12 fetuses carried a recurrent CNV and six carried a pathogenic recurrent CNV, corresponding to 3.45% and 1.72%, respectively. The investigators described several concordant examples, including a 22q11.2 deletion with conotruncal and nuchal findings, a distal 1q21.1 deletion with left-sided cardiac hypoplasia and a 17q12/HNF1B deletion associated with a renal phenotype. They also reported discordant findings, such as a proximal 16p11.2 deletion in a fetus with myelomeningocele and Chiari II malformation, emphasizing that a pathogenic classification does not by itself establish that a CNV explains an ultrasound phenotype.

Inheritance added another layer to interpretation. Among 46 recurrent-CNV carriers for whom parental information was available, only one transmitting parent had a documented clinical diagnosis; the remaining information came from referral records rather than systematic parental examination. All 11 prenatal transmitting parents were recorded as clinically unaffected. In the prenatal cohort, five of six de novo findings were pathogenic, compared with two of 11 inherited findings, while nine inherited events were variants of uncertain significance or benign. These numbers were small and descriptive, but they illustrate the difficulty of predicting fetal outcomes from recurrence and inheritance alone, particularly for low-penetrance duplications and other regions with variable expressivity.

The authors said the results support region- and dosage-specific reporting of recurrent CNVs, with ClinGen reference coordinates, copy-number direction, ACMG/ClinGen classification, inheritance and phenotype concordance considered separately. This would help distinguish adjacent but clinically different intervals, such as proximal and distal 16p11.2 or the several recurrent regions around 22q11.21. The analysis was limited by its retrospective single-center design, unequal cohort sizes and periods, referral-based ascertainment, small subgroups and wide confidence intervals. It also excluded non-recurrent pathogenic CNVs, used two array platforms with different resolutions and reporting thresholds, and lacked systematic follow-up of pregnancy and postnatal outcomes. Consequently, its frequencies describe a clinical microarray referral population rather than population prevalence, and the authors did not estimate penetrance from the cohort.

Subject of Research: ClinGen-based classification of recurrent copy-number variants in prenatal and postnatal chromosomal microarray testing

Article Title: Recurrent CNVs in constitutional CMA: a ClinGen-anchored single-center postnatal and prenatal experience

Article References: Satkın, N. B., Atlı, E., Yalcintepe, S., Çelik, K. M., & Gürkan, H. (2026). Recurrent CNVs in constitutional CMA: a ClinGen-anchored single-center postnatal and prenatal experience. Frontiers in Genetics, 17, Article 1960791. https://doi.org/10.3389/fgene.2026.1960791

Image Credits: AI Generated

DOI: 10.3389/fgene.2026.1960791

Keywords: recurrent copy-number variants, chromosomal microarray, ClinGen, ACMG classification, prenatal diagnosis, postnatal diagnosis, dosage sensitivity, non-allelic homologous recombination, cytogenomics, Recurrent, CNVs, constitutional

The 16p13.11 region is a genomic trouble spot. It is packed with low-copy repeats, segments of DNA that are nearly identical in sequence and sit in repeating blocks along the chromosome. During DNA replication and repair, these near-identical sequences can misalign, and when the cellular machinery recombines the wrong pair, chunks of the genome are deleted or duplicated. This process, called non-allelic homologous recombination, makes 16p13.11 a recurrent hotspot for copy number variants, the gains and losses of DNA segments that underlie a family of genomic disorders. Duplications and deletions in this region have been linked in the medical literature to developmental delay, intellectual disability, language impairment, behavioral abnormalities, attention-deficit/hyperactivity disorder, autism spectrum disorder, distinctive facial features, and cardiovascular anomalies.

What makes 16p13.11 microduplication so difficult is that it does not behave like a classic disease-causing mutation. Many carriers are apparently healthy adults, and the duplication is frequently inherited from a parent who shows no signs of any related condition. Geneticists describe such variants as having incomplete penetrance, meaning not everyone who carries the extra DNA shows effects, and variable expressivity, meaning those who are affected can show very different symptoms. In 2024, the Clinical Genome Resource assigned the region a triplosensitivity score of 2, a rating that suggests moderate but not definitive pathogenic potential when an extra copy is present.

The Wenzhou team used chromosomal microarray analysis, a technique recommended by the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine for prenatal diagnosis, to scan fetal DNA extracted from uncultured amniotic fluid cells. The platform they used, the CytoScan 750K array, detects copy number changes across the whole genome at high resolution. The 19 duplications they found ranged in size from 0.80 to 1.60 megabases and spanned between 7 and 13 genes cataloged in the Online Mendelian Inheritance in Man database. Every duplicated segment overlapped the critical region associated with 16p13.11 microduplication syndrome, and all coordinates were mapped against the hg19 reference genome.

The reasons the pregnancies reached amniocentesis in the first place were varied and mostly unrelated to the duplication itself. Seven cases were prompted by advanced maternal age, five by a history of adverse pregnancy outcomes, three by high-risk serum screening results, and four by abnormal ultrasound findings. Those four ultrasound cases were strikingly heterogeneous. One fetus had increased nuchal translucency, a thickening of the fluid-filled space at the back of the neck. Another showed a constellation of severe problems: growth lagging about three weeks behind dates, fluid accumulating in both the chest and abdomen, an enlarged heart, and tricuspid regurgitation. A third displayed right upper limb anomalies consistent with radial dysplasia, including a short, curved ulna, an extremely short radius, and marked angling of the wrist. The fourth had a single umbilical artery and an echogenic intracardiac focus in the left ventricle, a bright spot on the heart that is usually benign.

Pedigree analysis, in which both parents are tested to determine whether the duplication was inherited or arose newly in the fetus, was completed in only five of the 19 cases. In four of those five, the duplication came from a phenotypically normal mother or father; one was de novo, appearing for the first time in the child. Notably, after comprehensive genetic counseling, the parents of all five fetuses with confirmed inheritance information chose to continue their pregnancies, a decision the authors emphasize reflects individual family choices rather than a general recommendation.

The pregnancy outcomes and follow-up data form the heart of the study. Three couples, all counseled by multidisciplinary teams, elected to terminate their pregnancies, including two of the cases with severe multi-organ ultrasound abnormalities. The remaining 16 fetuses were carried to term, and postnatal follow-up was ultimately available for 14 children ranging in age from 10 months to 10 years. The picture that emerged was largely reassuring. Five children were reported to be developing ahead of their age-matched peers, and seven showed no abnormalities at all according to their parents. One child, now nine years old, showed delayed development: walking began at 17 months and first words did not arrive until age three, with parents describing average expressive language ability. One infant was hospitalized at birth because of a ventricular septal defect, a hole in the wall separating the heart’s lower chambers, but subsequent examinations revealed no additional problems. Two children were lost to follow-up.

The authors are careful about what these outcomes do and do not prove. The child with developmental delay carried a 1.25 megabase duplication spanning ten genes, including NDE1, a gene with established roles in neurogenesis and the development of the cerebral cortex. That association fits the neurodevelopmental spectrum described for 16p13.11 imbalances. Yet other children in the same cohort carried duplications of similar size or gene content and developed normally, which demonstrates that duplication size and gene count alone cannot predict how any individual child will fare. The region also contains ABCC6, whose loss-of-function variants cause abnormal tissue mineralization, and MYH11, which is involved in smooth muscle and has been linked to cardiovascular disease, but the study found no evidence that extra copies of these genes directly caused the observed heart defect. Background genetic modifiers probably contribute to the variability, though their individual effects remain beyond the reach of this data set.

For prenatal counselors, the practical message is one of calibrated uncertainty. The researchers argue that 16p13.11 microduplication should be presented to expectant parents neither as a benign curiosity nor as a definite diagnosis, but as a susceptibility variant with reduced penetrance and variable expressivity. Interpretation should weave together the fetal ultrasound picture, the characteristics of the duplication itself, parental testing results where available, and family history. An inherited duplication from a healthy parent is somewhat reassuring but does not eliminate risk, while a de novo duplication or one accompanied by significant structural abnormalities warrants a broader discussion of possible outcomes. After birth, the authors recommend surveillance guided by the child’s clinical course rather than the laboratory result: close monitoring of speech and motor milestones, attention to learning and behavioral concerns as the child grows, and cardiac review when indicated, since some effects may only surface later in childhood or adulthood.

The study’s limitations are acknowledged candidly. It was retrospective and single-center, the number of cases was small, parental testing was not systematically performed, and developmental outcomes relied mainly on telephone interviews and parental reports rather than standardized assessments for every child. For the terminated pregnancies, no systematic fetal autopsy or additional genetic testing was carried out, so other causes of the severe ultrasound findings cannot be excluded. Even so, the results align with recent prenatal series from other Chinese centers, which similarly found that most live-born children with the duplication showed no major abnormalities in early follow-up while a minority experienced neurodevelopmental or cardiac problems. Taken together, the evidence supports treating 16p13.11 microduplication as a finding to be understood, monitored, and discussed honestly, not feared automatically, and it underscores how much modern prenatal genetics still depends on long-term follow-up to turn raw copy number calls into meaningful guidance for families.

Subject of Research: Prenatal detection and postnatal outcomes of 16p13.11 microduplication identified by chromosomal microarray in a large pregnancy cohort

Article Title: Prenatal Diagnosis and Postnatal Follow‐Up of 19 Fetuses With 16p13.11 Microduplication in a Cohort of 12,038 Pregnancies From South Zhejiang

Article References: Lv, X., Li, S., Zhou, L., Wang, R., Yu, Y., Xu, C., Xu, X., Tang, X., & Li, H. (2026). Prenatal Diagnosis and Postnatal Follow‐Up of 19 Fetuses With 16p13.11 Microduplication in a Cohort of 12,038 Pregnancies From South Zhejiang. Molecular Genetics & Genomic Medicine, 14(10), Article e70324. https://doi.org/10.1002/mgg3.70324

Image Credits: AI Generated

DOI: 10.1002/mgg3.70324

Keywords: 16p13.11 microduplication, chromosomal microarray analysis, copy number variant, prenatal diagnosis, incomplete penetrance, genetic counseling, developmental delay, ventricular septal defect, low-copy repeats, NDE1, amniocentesis, genotype-phenotype correlation

The research team, led by Shivani Mishra and corresponding author Royana Singh, recruited 125 fetal specimens from pregnancies that ended in loss, ultimately analyzing 118 samples after applying predefined exclusion criteria designed to guard against contamination and degraded tissue. The specimens, which included products of conception and fetal tissues such as skin, muscle, and cartilage obtained during autopsy, underwent DNA extraction and quantitative fluorescent PCR, a technique that amplifies short tandem repeat markers scattered across chromosomes 13, 18, 21, X, and Y. By measuring the relative quantity of fluorescent signals at these markers, QF-PCR can detect the most common whole-chromosome imbalances, the trisomies and monosomies that account for the majority of chromosomally abnormal miscarriages, often within a day or two of sample receipt.

The results were sobering but clinically rich. Of the 118 samples analyzed, QF-PCR identified aneuploidy in 36 cases, a detection rate of 30.5 percent. Twenty of these were monosomies, in which an entire chromosome is missing from the fetal genome, and sixteen were trisomies, in which an extra copy is present. The remaining 82 samples appeared normal by this rapid screen. That nearly one in three lost pregnancies carried a whole-chromosome imbalance confirms the central role of aneuploidy in early pregnancy failure, and it also carries a practical message for genetic counseling: when an aneuploidy is identified as the cause of a loss, the recurrence risk for future pregnancies is generally low, information that can meaningfully reduce anxiety for couples facing the aftermath of repeated loss.

Beyond the raw detection numbers, the study teased out clinical associations that matter for patient management. Maternal age showed a statistically significant relationship with the presence of chromosomal abnormalities, echoing decades of reproductive biology linking the aging oocyte to meiotic segregation errors. More intriguing was the finding of a weak but statistically significant negative correlation between gestational age and aneuploidy risk, with a correlation coefficient of −0.238 and a p-value of 0.008855. In other words, the earlier the loss, the more likely it was to be chromosomally abnormal, a pattern consistent with the idea that grossly imbalanced embryos tend to fail early in development, while losses later in gestation are more often driven by other mechanisms, including immunological, endocrine, thrombotic, and anatomical factors.

But QF-PCR has a well-known blind spot. It interrogates a limited set of chromosomes and cannot see submicroscopic copy number variations, the deletions and duplications of genomic segments too small to alter chromosome number but large enough to remove or duplicate genes. To peer beneath that resolution floor, the team selected a subset of 30 samples, stratified by their QF-PCR outcomes, and subjected them to array comparative genomic hybridization. In aCGH, differentially labeled fetal and reference DNA are co-hybridized to a microarray carrying hundreds of thousands of immobilized genomic probes, and the fluorescence ratio at each probe reveals whether the corresponding region is deleted or duplicated in the fetal genome. This technique can detect imbalances ranging from roughly 100 kilobases upward, an order of magnitude finer than conventional karyotyping.

The aCGH analysis proved its worth. Within the 30-sample cohort, the researchers identified clinically relevant copy number variations spanning the spectrum of pathogenicity, including pathogenic and likely pathogenic variants as well as variants of uncertain significance, the latter category reflecting regions whose dosage sensitivity has not yet been firmly established. Each variant was interpreted according to the joint guidelines of the American College of Medical Genetics and the Clinical Genome Resource, the standard framework that weighs factors such as gene content, inheritance pattern, and overlap with established disease loci before assigning a clinical classification.

Among the genes caught in deleted or duplicated segments were several with compelling biological narratives. CFHR3, a member of the complement factor H-related gene family, participates in the regulation of the complement cascade, the arm of innate immunity whose dysregulation has been implicated in inflammatory damage at the maternal-fetal interface. TNFRSF4 encodes a tumor necrosis factor receptor superfamily member with roles in immune cell signaling and tolerance. UGT2B17 belongs to the uridine diphosphate glucuronosyltransferase family, a set of metabolic detoxification enzymes whose variation has previously been linked to recurrent miscarriage, possibly through altered clearance of environmental and endogenous compounds. CD24 and MSR1 are involved in immune signaling and macrophage scavenger function, respectively, while the pregnancy-specific glycoprotein gene family, or PSG genes, is expressed almost exclusively in the placenta and is thought to modulate maternal immune tolerance of the fetus.

To move from gene lists to mechanism, the authors turned the implicated genes loose on a battery of bioinformatics tools. Using FunRich and WebGestalt for functional annotation, KEGG for pathway enrichment, and STRING for protein-protein interaction network construction, the team asked what biological themes united the disrupted loci. The answer converged on a coherent set of processes: immune-inflammatory signaling, endocrine regulation, lipid metabolism, extracellular matrix remodeling, and placental development. The involvement of TNF receptor signaling, MAPK cascades, and interleukin-1-related pathways emerged from the network analyses, weaving the copy number variations into the same immunological tapestry that independent studies have implicated in unexplained recurrent loss, including work on maternal B cell signaling and natural killer cell-mediated immunopathology.

The authors are careful, appropriately so, to frame the pathway findings as exploratory. The cohort of 30 microarray samples is modest, and several of the variants of uncertain significance may prove benign as genomic databases mature. The statistical associations between individual CNVs and miscarriage phenotypes will require validation in larger, well-powered cohorts with matched controls before they can inform clinical decision-making. Still, the architectural message of the study is clear: sequential testing with QF-PCR followed by aCGH captures abnormalities that neither method detects alone, and it does so at a fraction of the cost and turnaround time of broader approaches such as whole-genome sequencing.

That message lands at a moment of ferment in reproductive genetics. European Society of Human Reproduction and Embryology guidelines define recurrent pregnancy loss as two or more consecutive losses, and professional societies have been wrestling with the optimal diagnostic workup of lost pregnancy tissue for years. Previous studies comparing karyotyping with molecular methods have shown that conventional cytogenetics suffers from culture failure and maternal cell contamination, problems that DNA-based methods largely sidestep. The Banaras Hindu University team’s approach, anchored in a real clinical diagnostic laboratory serving a population with limited access to advanced genomic testing, demonstrates that a tiered molecular protocol is feasible and productive outside of well-funded Western centers.

For couples enduring the grief of repeated loss, the study’s findings translate into a concrete recommendation worth discussing with a genetic counselor: comprehensive cytogenetic analysis of lost pregnancy tissue is not merely an academic exercise. Identifying an aneuploidy or a pathogenic copy number variant can close the diagnostic loop, refine recurrence risk estimates, and in some cases guide the management of subsequent pregnancies, including targeted prenatal or preimplantation genetic testing. Conversely, a normal molecular karyotype redirects the clinical search toward the non-genetic contributors, from antiphospholipid syndrome to uterine anomalies.

The work also adds to a growing map of the genomic landscape of pregnancy failure, in which the PSG gene cluster on chromosome 19, the complement factor H-related locus, and immune receptor genes recur across independent cohorts. As genome-wide datasets accumulate and functional studies test the dosage sensitivity of these loci, variants of uncertain significance will gradually be reclassified, and the exploratory pathway signals reported here may harden into causal mechanisms. Until then, the study stands as both a practical diagnostic template and a hypothesis-generating catalog of the fragile genetic architecture underlying one of medicine’s most quietly devastating problems.