Lipoid Congenital Adrenal Hyperplasia Due to Steroidogenic Acute Regulatory Protein (StAR) Deficiency in a 46,XY Child With a Female Phenotype: A Case Report

Primary adrenal insufficiency in childhood is frequently associated with inherited disorders.Lipoid congenital adrenal hyperplasia due to steroidogenic acute regulatory protein (StAR) deficiency is a rare disorder characterized by impaired mitochondrial cholesterol transfer and deficient adrenal and gonadal steroidogenesis.We report a five-year-old child raised as a girl who had been diagnosed with primary adrenal insufficiency at three months of age and was receiving hydrocortisone and fludrocortisone.Physical examination showed female-appearing external genitalia without virilization and Tanner stage I development.Biochemical evaluation demonstrated markedly elevated adrenocorticotropic hormone with profoundly low morning cortisol and globally reduced steroidogenesis, including low 17hydroxyprogesterone, androstenedione, dehydroepiandrosterone sulfate, and free testosterone.Karyotyping revealed 46,XY.Anti-Müllerian hormone and inhibin B concentrations were compatible with preserved Sertoli cell secretory activity and supported the presence of testicular tissue despite severely impaired androgen production.A contrast-enhanced abdominal and pelvic magnetic resonance imaging study was subsequently re-evaluated in the picture archiving and communication system by an expert radiologist.Targeted review identified structures compatible with bilateral undescended testes, with the right probable gonad in the inguinal canal and the left probable gonad in the abdominal cavity.Magnetic resonance imaging and transabdominal ultrasonography also demonstrated a tubular structure posterior to the bladder that was considered compatible with a rudimentary vaginal canal; no definite uterine structure was identified on targeted review.Molecular testing identified a homozygous pathogenic truncating variant in STAR (NM_000349.3:c.577C>T;p.Arg193*), establishing the diagnosis of lipoid congenital adrenal hyperplasia due to StAR deficiency.This case highlights the value of integrating steroid profiles, cytogenetic findings, Sertoli cell biomarkers, molecular testing, and expert imaging review in children with primary adrenal insufficiency and 46,XY differences of sex development.