Mortality and incidence in women with 47,XXX and variants

47,XXX syndrome is among the most common sex chromosomal disorders; however, apart from screening surveys, epidemiological data are limited. We report data on 136 women diagnosed with 47,XXX or a compatible karyotype in Denmark during 1963-2008. We identified an incidence of 10.7 per 100,000 liveborn girls, which was lower than expected and was stable during the study period. Age at diagnosis ranged from 0 to 73 years, with a diagnostic delay of 18.2 years or more in half the 47,XXX persons. We compared persons with 47,XXX with an age-matched cohort of the female background population (born same year and month), identified in Statistics Denmark (n = 13,400). Mortality was significantly increased in total with a hazard ratio of 2.5 (1.6-3.9), corresponding to a difference in median survival of 7.7 years. When we divided causes of death into 19 chapters according to the International Classification of Diseases, a generally increased mortality was identified in all informative chapters. Furthermore, we identified significantly increased mortality in cardiovascular diseases, in the chapter concerning chromosomal and congenital defects, and in the chapter of unspecified diseases. Better delineation of the clinical phenotype of 47,XXX is needed; available information does not readily explain the increased mortality.