Mortality and cancer incidence in women with extra X chromosomes: a cohort study in Britain.
About one woman in 1,000 has an extra X chromosome, but such women have no recognised characteristic somatic features and little is known about their long-term health and cancer risks. We conducted a cohort study of mortality and cancer incidence in 542 women diagnosed with X polysomy at 25 cytogenetic centres in Britain since 1959. Fifty-nine deaths occurred during follow-up to mid-2004. Mortality was significantly raised (standardised mortality ratio (SMR) = 2.5 (95% confidence interval (CI) 1.9-3.2)), with excess deaths due particularly to cardiovascular disease (SMR = 2.5 (95% CI 1.5-3.8)) and respiratory disease (SMR = 4.0 (95% CI 1.7-7.9)). Risks of cancer incidence and cancer mortality overall were not raised, but there was significantly raised mortality from non-Hodgkin's lymphoma (NHL) (SMR = 10.4 (95% CI 1.3-37.6); based on 2 cases). The data indicate that mortality in women diagnosed with X polysomy is considerably raised. The raised risk of NHL is seen also in males with more than one X chromosome, and hence although unexpected and based on small numbers, it might indicate the action of a gene on the X chromosome, possibly in the pseudoautosomal region, that escapes X-inactivation.
Swerdlow
Anthony J
AJ
Section of Epidemiology, Institute of Cancer Research, Sutton, SM2 5NG, UK. anthony.swerdlow@icr.ac.uk
Schoemaker
Minouk J
MJ
Higgins
Craig D
CD
Wright
Alan F
AF
Jacobs
Patricia A
PA
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D041321:Chromosomes, Human, X; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000235:genetics / Q000401:mortality*; D012189:Retrospective Studies; D012729:Sex Chromosome Aberrations; D006113:United Kingdom; D049951:X Chromosome Inactivation / Q000235:genetics