Adrenal Insufficiency, Sex Reversal, and Angelman Syndrome due to Uniparental Disomy Unmasking a Mutation in CYP11A1

Abstract

Background/Aims: Cholesterol side-chain cleavage enzyme (P450scc) deficiency is a rare genetic disorder causing primary adrenal insufficiency with or without a 46,XY disorder of sexual development (DSD). Herein, we report a case of the combination of primary adrenal insufficiency, a DSD (testes with female external genitalia in a setting of a 47,XXY karyotype), and Angelman syndrome. Methods: Comprehensive genetic analyses were performed, including a single nucleotide polymorphism microarray and whole-exome sequencing. In vitro studies were performed to evaluate the pathogenicity of the novel mutation that was identified by whole-exome sequencing. Results: The patient was found to have segmental uniparental disomy (UPD) of chromosome 15 explaining her diagnosis of Angelman syndrome. Whole-exome sequencing further revealed a novel homozygous intronic variant in CYP11A1, the gene encoding P450scc, found within the region of UPD. In vitro studies confirmed that this variant led to decreased efficiency of CYP11A1 splicing. Conclusion: We report the first case of the combination of 2 rare genetic disorders, Angelman syndrome, and P450scc deficiency. After 20 years of diagnostic efforts, significant advances in genetic diagnostic technology allowed us to determine that these 2 disorders originate from a unified genetic etiology, segmental UPD unmasking a novel recessive mutation in CYP11A1.