A young girl with partial chromosome 15q11.2 microduplication: a case report in Cameroon

The 15q11.2 BP1-BP2 microduplication is a rare copy number variant associated with neurodevelopmental disorders, dysmorphic features, and variable expressivity. Unlike complete trisomy 15, this microduplication involves a 300 kb segment containing four genes: NIPA1, NIPA2, CYFIP1, and TUBGCP5. Few cases have been reported in sub-Saharan Africa.

We report a case of a nine-year-old girl born small for gestational age who presented with feeding difficulties, dysmorphic signs, failure to thrive, and learning disabilities. Silver-Russell syndrome was initially considered as a differential diagnosis. Chromosomal microarray analysis (CMA) using Agilent 44 K oligonucleotide array-CGH (GRCh37/hg19 genome build) revealed an interstitial 15q11.2 microduplication of 300.5 kb between breakpoints BP1 and BP2, classified as arr[GRCh37] 15q11.2(22784523_23085096)x3. Parental testing confirmed maternal origin. She received nutritional support and levothyroxine for central hypothyroidism. After a 3-year follow-up, she showed improvement in growth parameters and school performance.

The 15q11.2 BP1-BP2 microduplication may be underdiagnosed in Africa due to limited access to genetic testing. This case highlights the importance of chromosomal microarray analysis in children presenting with developmental delay and failure to thrive in resource-limited settings.