Population studies of INV(9) chromosomes in 4,300 Japanese: incidence, sex difference and clinical significance.
Population incidence of a chromosome 9 with an inversion of qh, inv(9), was surveyed using C-banding in a total of 4,367 Japanese which consisted of five patient groups and a normal control group. The inv(9) incidence was 1.65% in the normal control group (n = 1,513) and 1.52% in the Down syndrome patient group (n = 1,246). The incidence of female carriers was 1.7 times higher than that of male carriers in the above two groups. The sex difference was significant (p < 0.05). Moreover, the incidence in the 47,XXY male group (n = 277) was slightly higher than female carrier incidences. The excess of carriers about 2 times was observed in the habitual abortion couple group (n = 694) and the spontaneous abortus group (n = 181), both having normal karyotypes. The present data probably indicate the existence of a genetic effect of inv(9) on human reproductive performance, while they could not explain the sex difference found in inv(9) carriers. Our speculation for the sex difference has been presented.
Yamada
K
K
Division of Genetics, National Medical Center, Tokyo, Japan.
D000026:Abortion, Habitual / Q000235:genetics; D000022:Abortion, Spontaneous / Q000235:genetics; D000328:Adult; D002675:Child, Preschool; D002869:Chromosome Aberrations; D007446:Chromosome Inversion; D002899:Chromosomes, Human, Pair 9; D004314:Down Syndrome / Q000235:genetics; D005260:Female; D005828:Genetics, Population; D006579:Heterozygote; D006801:Humans; D007223:Infant; D007564:Japan; D007713:Klinefelter Syndrome / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009845:Oligospermia / Q000235:genetics; D011247:Pregnancy; D012744:Sex Ratio; D013223:Statistics as Topic