[Identification of a novel missense mutation of the DAX-1 gene in a Chinese pedigree with X-linked adrenal hypoplasia congenita].

Objective: Inactivating mutations of DAX-1 give rise to the X-linked form of adrenal hypoplasia congenita (AHC). Affected individuals are at risk of early postnatal Addisonian crisis, but the variable phenotypic expression of DAX-1 insufficiency renders this diagnosis challenging. This study aimed to understand the clinical features and identify DAX-1 gene mutation of the affected individuals and their relatives in a Chinese adrenal hypoplasia congenita kindred.

Methods: The proband was diagnosed as adrenal insufficiency shortly after birth and his elder cousin was also diagnosed as having this disease at the age of about 8 years. Clinical data were obtained from 2 affected individuals when they were hospitalized into the department of pediatrics, Ruijin Hospital in 2006; 20 peripheral blood samples were obtained from the affected individuals and their relatives; exons in DAX-1 gene were amplified, and PCR product was purified and sequenced directly for analyzing mutation.

Results: A novel hemizygous mutation (T785C) was found in DAX-1 gene in both patients. Some clinical features such as the age of onset were different although these 2 patients carried the same mutation. There were 5 carriers of this mutation in the patients' maternal pedigree.

Conclusion: The results suggested that adrenal hypoplasia congenita in this kindred was caused by a novel mutation (T785C) in DAX-1 gene, and the same mutation can give rise to the variable phenotype.