A compound heterozygous mutation in CYP17A1 gene in a female subject with partial 17α-hydroxylase/17, 20 lyase deficiency

Abstract

To explore the clinical and molecular genetic characteristics of a Chinese female patient with partial 17α-hydroxylase/17, 20 lyase deficiency (17OHD), a rare type of congenital adrenal hyperplasia. Her clinical features and laboratory data were collected. Genomic DNA was extracted from leukocytes of peripheral blood of her and her mother. All eight exons of CYP17A1 gene, including flanking regions of introns, were amplified by PCR. The mutations of CYP17A1 gene were identified by direct sequencing or cloning and sequencing the amplified DNA fragments. The patient presented with hypertension, hypokalemia and irregular menstruation. DNA sequencing results demonstrated a compound heterozygous mutation in CYP17A1 gene. One allele of her had the deletion of phenylalanine (TTC) at either codon 53 or 54 and the other allele contained a base transversion at codon 329 (TAC/AA) and leading to a missense mutation of tyrosine to lysine and the open reading frame shift following this codon to produce a truncated enzyme with 417 amino acids and without activity site. Her mother was a heterozygous carrier of the latter allele. The partial 17OHD in this patient is caused by a compound heterozygous mutation in CYP17A1 gene.