Do reduced levels of steroid 21-hydroxylase confer a survival advantage in fetuses affected by sex chromosome aberrations?
We investigated whether molecular defects in the CYP21 gene were detectable in two common sex chromosome aberrations, the Turner and the Klinefelter syndromes. We found abnormal 17-hydroxyprogesterone levels after adrenal stimulation in 26/60 (43.3%) patients affected by these chromosome aberrations, as compared with only 11/68 (16.2%) normal controls (P=0.0014, odds ratio 4.0). Screening of the CYP21 gene identified a single Val281Leu missense mutation in exon 7 in 9/63 (14.3%) of the patients, all nine of whom were heterozygote carriers; the mutation frequency was significantly higher than in the general population (P=0.007, odds ratio=3.5). The hormonal and molecular data indicate that these common sex chromosome aberrations are associated with a remarkably high frequency of steroidogenic defects. It may be hypothesised that reduced levels of steroid 21-hydroxylase could confer a survival advantage, leading to a successful pregnancy.
Mantovani
Vilma
V
Laboratorio Centralizzato Settore Genetica, Policlinico S.Orsola-Malpighi, Bologna, Italy. mantovan@med.unibo.it
Dondi
Elisabetta
E
Larizza
Daniela
D
Cisternino
Mariangela
M
Bragliani
Michela
M
Viggiani
Mariagabriella
M
Martinetti
Miryam
M
Cuccia
Mariaclara
M
D019326:17-alpha-Hydroxyprogesterone / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D005260:Female; D005328:Fetal Viability / Q000235:genetics* / Q000502:physiology; D005333:Fetus / Q000502:physiology*; D006801:Humans; D007713:Klinefelter Syndrome / Q000235:genetics; D008297:Male; D009154:Mutation; D012729:Sex Chromosome Aberrations; D013255:Steroid 21-Hydroxylase / Q000235:genetics / Q000378:metabolism*; D014424:Turner Syndrome / Q000235:genetics
D019326:17-alpha-Hydroxyprogesterone; D000324:Adrenocorticotropic Hormone; D013255:Steroid 21-Hydroxylase