A rare de novo contiguous 15q11.1-q13.3 duplication with tetrasomy (CN=4) and adjacent trisomy (CN=3) associated with severe global developmental delay, autism spectrum disorder, and subclinical epileptiform discharges: a case report and literature review.

A de novo 15q11.1-q13.3 duplication with tetrasomy and trisomy was linked to severe neurodevelopmental delays and autism in a girl, expanding known genomic variations.

• Why it matters: Understanding complex chromosomal rearrangements is crucial for accurate diagnosis and targeted interventions in neurodevelopmental disorders, which are often misattributed to prematurity.
• What they did: The team used trio whole-genome sequencing and copy number variation analysis to identify a rare contiguous duplication involving a 10.34 Mb tetrasomic segment and a 2.40 Mb trisomic segment in a Chinese girl.
• The result: Findings highlight the importance of high-resolution genomic testing for complex rearrangements, enabling better diagnosis and emphasizing early genetic evaluation in children with severe developmental impairments.