When Chromosome 15 Duplicates: A Clinical-Genetic Challenge
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Authors
DOI:
https://doi.org/10.37980/im.journal.ggcl.en.20252717Keywords:
Dup15q syndrome, Chromosome 15q11-q13, Array-CGH, Autism spectrum disorder, EpilepsyAbstract
Background: Chromosome 15q11–q13 duplication syndrome (Dup15q) is a rare neurodevelopmental disorder caused by additional copies of a genomic region enriched in imprinted genes essential for normal neuronal function. It is commonly associated with autism spectrum disorder (ASD), epilepsy, hypotonia, global developmental delay, and intellectual disability. Case presentation: We report the case of a 31-year-old male with a longstanding history of refractory epilepsy, autism spectrum disorder, and intellectual disability. Genetic evaluation using array-comparative genomic hybridization (array-CGH) combined with single-nucleotide polymorphism (SNP) analysis identified a de novo interstitial heterozygous duplication of 10.03 Mb involving the 15q11.2–q13.3 region. The duplicated segment encompasses multiple genes with key roles in neurodevelopment, including UBE3A, GABRB3, GABRA5, SNRPN, and NDN. Parental testing by multiplex ligation-dependent probe amplification (MLPA) was negative, confirming a non-inherited origin. Establishing the molecular diagnosis allowed precise clinical classification, informed therapeutic decision-making, and enabled appropriate genetic counseling. Conclusion: This case illustrates the diagnostic value of array-CGH in patients with complex neurodevelopmental phenotypes and emphasizes the importance of early genetic assessment in individuals presenting with ASD and epilepsy. Identification of pathogenic copy number variants such as Dup15q has significant implications for prognosis, clinical management, and family counseling.
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