Causal and Candidate Gene Variants in a Large Cohort of Women With Primary Ovarian Insufficiency.

Context: A genetic etiology likely accounts for the majority of unexplained primary ovarian insufficiency (POI).

Objective: We hypothesized that heterozygous rare variants and variants in enhanced categories are associated with POI.

Design: The study was an observational study.

Noncoding sequence variants define a novel regulatory element in the first intron of the N-acetylglutamate synthase gene.

N-acetylglutamate synthase deficiency is an autosomal recessive urea cycle disorder caused either by decreased expression of the NAGS gene or defective NAGS enzyme resulting in decreased production of N-acetylglutamate (NAG), an allosteric activator of carbamylphosphate synthetase 1 (CPS1). NAGSD is the only urea cycle disorder that can be effectively treated with a single drug, N-carbamylglutamate (NCG), a stable NAG analog, which activates CPS1 to restore ureagenesis. We describe three patients with NAGSD due to four novel noncoding sequence variants in the NAGS regulatory regions.