An extra X chromosome among adult women in the Million Veteran Program: A more benign perspective of trisomy X.

Abstract

Despite affecting in 1 in every 1000 females, remarkably little is known about trisomy X syndrome (47,XXX), especially among older adults who are undiagnosed. In this study, we aimed to determine the prevalence of 47,XXX among females enrolled in the Million Veterans Program (MVP; mean age 50.2 ± 13.6 years), and compare broad health outcomes between females with 47,XXX and 46,XX matched controls. We identified 61 females with an additional X chromosome, corresponding to a prevalence of 103 per 100,000 females; 27.9% had been clinically diagnosed. Females with 47,XXX had taller stature (+6.1 cm, p < 0.001), greater rate of outpatient encounters (p = 0.026), higher odds of kidney disease (odds ratio [OR] = 12.3; 95% confidence interval [CI] 2.9-51.8), glaucoma (OR = 5.1; 95% CI 1.5-13.9), and congestive heart failure (OR = 5.6; 95% CI 1.4-24.2), and were more likely to be unemployed (p = 0.008) with lower annual income (p = 0.021) when compared with 46,XX controls of the same age and genetic ancestry. However, there were no differences in the rates of other encounter types, Charlson Comorbidity Index, all other medical and psychological diagnoses, military service history or quality of life metrics. In conclusion, in this aging and predominately undiagnosed sample, 47,XXX conferred few differences when compared with matched controls, offering a more reassuring perspective to the trisomy X literature.