15q11-q13 interstitial triplication is a rare condition resulting in a tetrasomy of imprinted genes in the Prader-Willi/Angelman critical region (PWACR), with only 12 cases reported to date. The genotype-phenotype correlation is advancing, with a range of varying features such as craniofacial dysmorphism, developmental delay (DD), hypotonia, ataxia, seizures, behavioral impairment, and autism spectrum disorder. We present an eight-year-old female patient who displays mild craniofacial dysmorphism (strabismus, arched eyebrows, midface hypoplasia, long philtrum, thin upper lip), global developmental delay, and all the previously reported neurological features in relation to tetrasomy of this region. Whole genome single nucleotide polymorphism (SNP) microarray analysis detected a 6.05 Mb triplication at 15q11.2-q13.1 and a 3.48 Mb duplication at 15q13.1-q13. Our patient is the first case to encompass the full spectrum of reported features related to tetrasomy of this region. In addition, she has a complex chromosomal rearrangement (CCR) spanning the largest region of chromosome 15q11-q13 thus far. Our study contributes to the genotype-phenotype correlation regarding developmental delay especially impacting speech, and expands the prognosis for achievement of developmental milestones with early utilization of intensive speech, physical, and occupational therapies. Finally, we acknowledge the barriers our patient and her family faced to access specialized genetic clinical care and advocate for expanded access to clinical genetic care for under-represented populations.
Chilakamarri, Lekha and Mellin, Lizbeth, "Complex Chromosomal Rearrangement Involving 15q11-q13 Interstitial Triplication in a Patient with a Severe Phenotype: A New Clinical Report" (2021). MEDI 9331 Scholarly Activities Clinical Years. 43.