Phenotypic Features Associated with Mutations in Steroidogenic Acute Regulatory Protein

Abstract

Mutations in the gene encoding steroidogenic acute regulatory protein (StAR) are the most common cause of lipoid congenital adrenal hyperplasia (lipoid CAH), a disorder characterized by adrenal insufficiency and deficient gonadal steroid synthesis, resulting in female external genitalia in both genetic sexes. We describe three new cases of lipoid CAH caused by novel mutations in the StAR gene. An XY subject of Yemeni descent presented with adrenal insufficiency and severe undervirilization. Magnetic resonance imaging (MRI) of the brain showed enlarged subarachnoid spaces consistent with frontal and temporal atrophy. Two XX siblings of Palestinian descent presented with neonatal adrenal insufficiency. One had a borderline intelligence quotient and features of attention deficit hyperactivity disorder. MRI showed areas of supratentorial white matter lesions. In her sister, MRI revealed a Chiari-I malformation. The XY subject was found to have a missense mutation (R182C). Both XX siblings had a dinucleotide deletion at nucleotides 327-328 that induces a frame shift that truncates the StAR protein after 68 amino acids. These cases broaden the spectrum of known StAR mutations and suggest that disorders of central nervous system development may arise because of StAR deficiency and/or the metabolic consequences of neonatal adrenal deficiency.