Multiplex Ligation-Dependent Probe Amplification Analysis of the <i>NR0B1</i><i>(DAX1)</i> Locus Enables Explanation of Phenotypic Differences in Patients with X-Linked Congenital Adrenal Hypoplasia

X-linked adrenal hypoplasia congenita (AHC) is a rare disorder characterized by primary adrenal insufficiency and hypogonadic hypogonadism. It is caused by deletions or point mutations of the NR0B1 gene, on Xp21. AHC can be associated with glycerol kinase deficiency, Duchenne muscular dystrophy and mental retardation (MR), as part of a contiguous gene deletion syndrome. A synthetic probe set for multiplex ligation-dependent probe amplification analysis was developed to confirm and characterize NR0B1 deletions in patients with AHC and to correlate their genotypes with their divergent phenotypes.