Objective To study Chinese children with congenital adrenal hyperplasia (CAH) in the types ofpoint mutation in steroid 21 - hydroxylase gene (CYP21). Methods By using PCR-ASO hybridization analysiswith amplified segments involving exon 3-4 and exon 6-8 of the gene to investigate for the type ofmutations. Results The results showed among 5 point mutations detected positive findings being in 28/66 (42%)of CAH chromosomes, or 17/33 (52%) of the CAH cases examined. The only 1 non - classic form CAH case wasfound as homonsous for val - 281→len mutation. Three classic cases were heterozygous for compound mutations asnitron 2 A, C→G associated with lie-172→Asn or lie - 172→Asn with Gin-318→stop. The other point mutationsall revealed as homozygous alleies with the most freguent matations as nitron 2A, C→G. No PCR product wereprovided by 3 cases who had been verilied by Southern blotting with CYP21 B gene deletion (not shown). NO pointmutations were illustrated in normal controls. Conclusion This report presentS data in 17/33 (52K) of Chinesechildren with CAH in CYP 21 B gene had point mutations documenting the type and location of mutation indiagnosis of CAH. Objective To study Chinese children with congenital adrenal hyperplasia (CAH) in the types of point mutation in steroid 21-hydroxylase gene (CYP21). Methods By using PCR-ASO hybridization analysis with amplified segments involving exon 3-4 and exon 6-8 of the gene to investigate for the type ofmutations. Results The results showed among 5 point mutations detected positive findings being in 28/66 (42%) of CAH chromosomes, or 17/33 (52%) of the CAH cases examined. The only 1 non - classic form CAH case wasfound as homonsous for val - 281 → len mutation. Three classic cases were heterozygous for compound mutations asnitron 2 A, C → G associated with lie-172 → Asn or lie-172 → Asn with Gin-318 → stop. The other point mutations were revealed as homozygous alleies with the most freguent matations as nitron 2A, C → G. No PCR product wereprovided by 3 cases who had been verilied by Southern blotting with CYP21 B gene deletion (not shown). NO point motions were illustrated in normal controls. C onclusion This report presentS data in 17/33 (52K) of Chinese children with CAH in CYP 21 B gene had point mutations documenting the type and location of mutation indiagnosis of CAH.