BACKGROUND: X-linked adrenal hypoplasia congenita (AHC) is caused by mutations in DAX-1 (NR0B1) playing a key role in adrenal and reproductive development.
CASE PRESENTATION: Herein we report a 2.5-year-old boy who presented with acute adrenal failure. Family history revealed unexplained death in three brothers of the patient's mother during infancy. Molecular analysis of the DAX-1 gene revealed the presence of a novel hemizygous mutation, c.870C>A in exon 1, leading to the formation of a premature stop codon. The same mutation was identified in the patient's mother. The truncated mutant protein is most likely misfolded, sequestered in the endoplasmic reticulum and therefore cannot bind to and activate its target DNA sequences in the nucleus.
CONCLUSIONS: DAX-1 mutation must be considered when diagnosis of primary adrenocortical insufficiency is made, especially if there is a history of unexplained death of maternal male relatives.