Case Report: Early multidisciplinary rehabilitation and longitudinal functional outcomes in a child with a maternally derived 15q11.2-q13.1 copy-number gain

Dup15q syndrome is a rare neurodevelopmental disorder associated with developmental delay, hypotonia or motor impairment, epilepsy or abnormal EEG findings, language impairment, and autism-related social-communication difficulties. This case report describes the clinical phenotype, rehabilitation management, and longitudinal functional trajectory of a male child with a maternally derived 15q11.2-q13.1 copy-number gain. The child presented in early infancy with feeding difficulty, delayed motor development, abnormal sleep EEG findings, delayed white-matter maturation on brain MRI, and later clinically significant autism-related social-communication impairment. Trio whole-exome sequencing with CNV analysis identified an approximately 8.21-Mb de novo 15q11.2-q13.1 copy-number gain. MS-MLPA demonstrated four copies across BP1-BP3 and approximately 75% SNRPN methylation, supporting maternal origin. Multidisciplinary rehabilitation began at 5 months and included physical, occupational, speech-language, feeding-related, caregiver-mediated, and later SMO-supported interventions. Serial BSID-II and GMFM-88 assessments were used descriptively, and ADOS-2 characterized autism-related behaviors. Developmental and gross motor scores increased over follow-up, and clinically meaningful milestones including stable head control, independent sitting, crawling, supported standing, and later independent walking were observed. However, because this is a single case without a comparator and follow-up overlapped with early childhood maturation, these changes should not be interpreted as direct evidence of treatment efficacy. This case highlights the value of phenotype-informed rehabilitation planning, developmental surveillance, caregiver involvement, and cautious interpretation of longitudinal outcomes in rare pediatric neurogenetic disorders.