RESUMEN
OBJECTIVES: Congenital adrenal hyperplasia (CAH) is an autosomal recessive disease which is most often caused by a deficiency in steroid 21-hydroxylase (21-OH), a microsomal enzyme encoded by the CYP21 gene. Although several CAH causing mutations have been identified in the CYP21 gene of patients with 21-OH deficiency, genotyping of the 21-OH locus is quite complex because of the high frequency of gene conversion and the presence of multiple mutations on single CAH alleles. This study was aimed to analyze the complete characterization of the CYP21 gene coding region in a Korean CAH patient and to conform the PCR-based single strand conformation polymorphism (SSCP) and heteroduplex analysis as a diagnostic tool. METHODS: We used a highly sensitive, non-radioactive method allowing PCR-based single strand conformation polymorphism (SSCP) analysis. This method was applied to the characterization of all the exons and intron-exon junctions of the CYP21 gene in one patients affected by the salt wasting form and 4 normal controls. RESULTS: In all samples showing SSCP abnormal band patterns, sequence analysis showed the presence of sequence variants. In particular, one mutation (I172N) which is already known to cause the disease and 3 silent mutations were detected. CONCLUSION: PCR-based single strand conformation polymorphism (SSCP) and heteroduplex analysis should be useful for the clinical application as a diagnostic tool for the detection of 21-hydroxylase gene mutations.