Molecular basis of aromatase deficiency in an adult female with sexual infantilism and polycystic ovaries.
We identified two mutations in the CYP19 gene responsible for aromatase deficiency in an 18-year-old 46,XX female with ambiguous external genitalia at birth, primary amenorrhea and sexual infantilism, and polycystic ovaries. The coding exons, namely exons II-X, of the CYP19 gene were amplified by PCR from genomic DNA and sequenced directly. Direct sequencing of the amplified DNA from the patient revealed two single-base changes, at bp 1303 (C-->T) and bp 1310 (G-->A) in exon X, which were newly found missense mutations and resulted in codon changes of R435C and C437Y, respectively. Subcloning followed by sequencing confirmed that the patient is a compound heterozygote. The results of restriction fragment length polymorphism analysis and direct sequencing of the amplified exon X DNA from the patient's mother indicate maternal inheritance of the R435C mutation. Transient expression experiments showed that the R435C mutant protein had approximately 1.1% of the activity of the wild type, whereas C437Y was totally inactive. Cysteine-437 is the conserved cysteine in the heme-binding region believed to serve as the fifth coordinating ligand of the heme iron. To our knowledge, this patient is the first adult to have described the cardinal features of a syndrome of aromatase deficiency. Recognition that such defects exist will lead to a better understanding of the role of this enzyme in human development and disease.
Ito
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Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas 75235.
Fisher
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CR
Conte
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FA
Grumbach
M M
MM
Simpson
E R
ER
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001141:Aromatase / Q000096:biosynthesis / Q000172:deficiency* / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D015153:Blotting, Western; D005091:Exons; D005260:Female; D005347:Fibroblasts / Q000201:enzymology; D006418:Heme / Q000378:metabolism; D006801:Humans; D007006:Hypogonadism / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010053:Ovary / Q000201:enzymology*; D017354:Point Mutation; D011085:Polycystic Ovary Syndrome / Q000201:enzymology / Q000235:genetics*; D016133:Polymerase Chain Reaction; D014162:Transfection
D009838:Oligodeoxyribonucleotides; D006418:Heme; D001141:Aromatase