X chromosome inactivation patterns in normal females.
Since one of the two X chromosomes is randomly inactivated at an early stage of female embryonic development, X-linked markers have been used to study the origin and development of various neoplastic disorders in affected heterozygous women; clonality assays have provided a useful tool to the understanding of the mechanisms underlying the development of neoplasia. Recently, a technique of clonal analysis has been devised that takes advantage of a highly polymorphic short tandem repeat within the X-linked human androgen receptor (AR) gene, resulting in a heterozygosity rate approaching 90%. The rapid expansion of the number of women now suitable for X inactivation analysis has however given rise to new controversies, one of the more troublesome being the possibility of a modification of the pattern of X- chromosome inactivation pattern in blood cells of elderly women. In the present study we analyze with the AR assay a group of 166 healthy females aged between 8 and 94 years, with no history of genetic or neoplastic familial disorders. We failed to find any correlation between age and X- chromosome inactivation pattern (r = 0.17), even subdividing the subjects in different age groups according to the criteria used by other researchers, and therefore reaffirm that, when tested for with well-standardized and accurate criteria, extremely unbalanced inactivation of the X chromosome is a truly uncommon phenomenon in normal women.
Racchi
O
O
Dipartimento di Oncologia Clinica e Sperimentale, Università di Genova and Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
Mangerini
R
R
Rapezzi
D
D
Rolfo
M
M
Gaetani
G F
GF
Ferraris
A M
AM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000235:genetics*; D001773:Blood Cells; D002648:Child; D004303:Dosage Compensation, Genetic; D005260:Female; D006801:Humans; D008875:Middle Aged; D011944:Receptors, Androgen / Q000235:genetics*; D014960:X Chromosome
D011944:Receptors, Androgen