Genetic and Clinical Characteristics of Chromosome 15q11-q13 Duplication Syndrome in Chinese Children

To enhance the diagnosis, management, and monitoring of Chinese children with chromosome 15q11-q13 duplication syndrome (dup15q) by analyzing their genetic and clinical characteristics. In this study, one Chinese prenatal case and 21 postnatal cases genetically diagnosed with dup15q syndrome underwent a detailed assessment of genetic and clinical characteristics. Most patients had normal prenatal (12/22, 54.5%) and neonatal (14/21, 66.7%) histories. Most symptoms were developmental delays (motor: 18/21, 85.7%; cognition: 13/21, 61.9%; language: 12/21, 57.1%). Other common features included autism spectrum disorder (ASD)-related behaviors (10/21, 47.6%) and seizures (7/21, 33.3%). Trisomy microduplications accounted for 54.5% (12/22), and tetrasomy microduplications accounted for 40.9% (9/22) of cases. We compared the phenotypic differences between the two groups using a composite score. One rare case of paternal duplication presented with early-onset obesity and tapered fingers resembling Prader-Willi syndrome (PWS). In addition, non-invasive prenatal testing (NIPT) detected int dup(15) in prenatal cases. Some patients with epilepsy were well controlled without anti-seizure drugs or monotherapy (3/7, 42.8%), while others had refractory epilepsy. Chinese children with dup15q exhibited high clinical heterogeneity, including multisystem developmental delays, ASD-related symptoms, and seizures. Phenotypic severity is influenced by multiple factors. NIPT may show positive findings, and chromosomal microarray analysis (CMA) combined with methylation analysis is important.