title: Sex chromosome loss and aging: in situ hybridization studies on human interphase nuclei.
abstract: A total of 1,000 lymphocyte interphase nuclei per proband from 90 females and 138 males age 1 wk to 93 years were analyzed by in situ hybridization for loss of the X and Y chromosomes, respectively. Both sex chromosomes showed an age-dependent loss. In males, Y hypoploidy was very low up to age 15 years (0.05%) but continuously increased to a frequency of 1.34% in men age 76-80 years. In females, the baseline level for X chromosome loss is much higher than that seen for the Y chromosome in males. Even prepubertal females show a rate of X chromosome loss, on the order of 1.5%-2.5%, rising to approximately 4.5%-5% in women older than 75 years. Dividing the female probands into three biological age groups on the basis of sex hormone function (< 13 years, 13-51 years, and > 51 years), a significant correlation of X chromosome loss versus age could clearly be demonstrated in women beyond age 51 years. Females age 51-91 years showed monosomy X at a rate from 3.2% to 5.1%. In contrast to sex chromosomal loss, the frequency of autosomal monosomies does not change during the course of aging: Chromosome 1 and chromosome 17 monosomic cells were found with a constant incidence of 1.2% and 1%, respectively. These data also indicate that autosome loss in interphase nuclei is not a function of chromosome size.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002878:Chromosomes, Human, Pair 1; D002886:Chromosomes, Human, Pair 17; D015342:DNA Probes; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D007223:Infant; D007231:Infant, Newborn; D007399:Interphase; D008297:Male; D008875:Middle Aged; D012730:Sex Chromosomes / Q000235:genetics*
chemical_list: D015342:DNA Probes