Steroid 5alpha-reductase 2 deficiency in two generations of a non-consanguineous Chinese family.

We report a Chinese family in which two family members were diagnosed to have steroid 5alpha-reductase 2 deficiency. The proband was an 8 year-old boy presenting with isolated micropenis. Mutational analysis revealed a homozygous mutation in exon 4 of the SRD5A2 gene, changing codon 227 from CGA to CAA, i.e. R227Q. The paternal granduncle of the proband has incomplete virilization in adulthood. Besides having the mutation R227Q, he has another mutation in exon 5 of the SRD5A2 gene, changing codon 246 from CGG to CAG, i.e. R246Q. To our knowledge, this is the first reported Chinese family diagnosed with steroid 5alpha-reductase 2 deficiency with identified molecular defects.