A new CYP17 gene abnormality was found in three Japanese
patients with 17α-hydroxylase
deficiency (17OHD). These patients were children from consanguineous
marriages, but from two
apparently unrelated families: one patient with 46, XY karyotype, and
two siblings with 46, XX and
46, XY karyotypes. They were all raised as girls and presented with
amenorrhea, eunuchoid
appearance and hypertension. Gene analysis revealed two base-pair (TG)
deletion in exon 5 (codons
300, 301) of the CYP17 gene. This deletion could be expected to
alter the reading frame resulting in
the lack of a haem-binding region (Cys 442) due to a premature stop
codon at position 333. This small
mutation may account for the patients' clinical manifestations of 17OHD.