Molecular Genetic Analysis of Tunisian Patients with a Classic Form of 21-Hydroxylase Deficiency: Identification of Four Novel Mutations and High Prevalence of Q318X Mutation

Maher Kharrat, Véronique Tardy, Ridha M'Rad, Faouzi Maazoul, Lamia Ben Jemaa, Mohamed Refaï, Yves Morel, Habiba Chaabouni
2004 Journal of Clinical Endocrinology and Metabolism  
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders mainly due to defects in the steroid 21hydroxylase (CYP21) gene. To determine the mutational spectrum in the Tunisian CAH population, the CYP21 active gene was analyzed in 51 unrelated patients using our cascade strategy (digestion by restriction enzyme, sequencing). All patients had a classical form of 21-hydroxylase deficiency. Mutations were detected in over 94% of the chromosomes examined. The most frequent
more » ... tion in the Tunisian CAH population was found to be Q318X, with large prevalence (35.3%), in contrast to 0.5-13.8% described in other series. Incidence of other mutations does not differ, as previously described: large dele-tions (19.6%), mutation in intron 2 (17.6%), and I172N (10.8%). Four novel mutations were found in four patients with the salt-wasting form. These four novel mutations include three point mutations that have not been reported to occur in the CYP21P pseudogene: R483W, W19X, 2669insC, and one small conversion of DNA sequence from exon 5 to exon 8. Our results have shown a good genotype/phenotype correlation in the case of most mutations. This is the first report of screening for mutations of 21-hydroxylase gene in the Tunisian population and even in the Arab population. (J Clin Endocrinol Metab 89: 368 -374, 2004)
doi:10.1210/jc.2003-031056 pmid:14715874 fatcat:kscddsvuvrai7mo3kqjxlfqlhi