NR0B1 and alternating hemiplegia of childhood: Congenital adrenal hypoplasia or adrenal hypoplasia congenita (AHC) is a rare disorder ascribed to mutations in three genes, namely, the dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (DAX-1/NROB1 gene), steroidogenic factor-1 gene (SF-1/NR5A1 gene), and Achalasia-Addisonianism-Alacrima syndrome gene (AAAS gene).