OBJECTIVETo analyze CYP21A2 gene mutation in two families with 21-hydroxylase deficiency (21-OHD) and to explore the correlation between genotype and clinical phenotype.

METHODSTwo patients with 21-OHD and their families were investigated. CYP21A2 gene mutation was analyzed by PCR and direct sequencing.

RESULTSThe probands from family 1 and 2 have been respectively diagnosed with simple virilizing and non-classical 21-OHD. Both showed increased baseline serum 17hydroxyprogesterone, testosterone and adrenocorticotropic hormone (ACTH), but had no evidence of salt loss. Computer tomography revealed bilateral adrenal hyperplasia in both patients. After 1 year treatment, both had conceived successfully. DNA sequencing revealed that the proband of family 1 had compound heterozygous mutations for IVS2 13 A>G and Ile172Asn. Her father was heterozygous for Ile172Asn, whilst her mother and brother were heterozygous for IVS213A/C>G. In family 2, the proband was heterozygous for Arg341Trp and Gln318X. Her father, sister and nephew were heterozygous for Arg341Trp, whilst her mother was heterozygous for Gln318X. her brother and niece were non-affected. Carriers of single heterozygous mutations in both families had no clinical sign.

CONCLUSIONIn both families, the disease has been caused by compound heterozygous mutations, for which there has been a good genotype-phenotype agreement. Screening of CYP21A2 gene can facilitate both diagnosis and genetic counseling.