NR5A1 gene mutations: clinical, endocrine and genetic features in two girls with 46,XY disorder of sex development.

Background: Steroidogenic factor 1, encoded by the NR5A1 gene, is a key regulator of endocrine function within the hypothalamic-pituitary-steroidogenic axis. Both homozygous, compound heterozygous and heterozygous mutations in the NR5A1 gene may determine 46,XY disorders of sex development (DSD).
Patients and Methods: NR5A1 gene sequencing was performed in a cohort of 6 patients with 46,XY DSD without specific diagnosis.
Results: Heterozygous NR5A1 gene mutations were found in 2 girls, aged 0.5 years and 14 years. The older girl harbored the c.250C>T transition in exon 4 (p.Arg84Cys), previously reported in a Japanese girl. The younger girl presented a de novo novel exon 6 heterozygous frameshift mutation (c.1074dupG) in codon 359 associated with the p.Gly146Ala polymorphism the latter inherited from her father. This baby showed severe impairment of androgen secretion from the first months of life. Overt adrenal insufficiency did not occur, but the older girl showed subnormal cortisol peak after ACTH stimulation.
Conclusions: NR5A1 gene mutations are a relatively frequent cause of 46,XY DSD in humans. Clear indications for management of these individuals remain elusive, mainly when diagnosis is made in infancy. Long-term monitoring of adrenal function should be recommended.