Incidence, prevalence, diagnostic delay, morbidity, mortality and socioeconomic status in males with 46,XX disorders of sex development: a nationwide study

Study question: What is the epidemiology and trajectory of health and socioeconomic status in males with 46,XX disorders of sex development (DSD)?

Summary answer: 46,XX DSD males had an increased overall morbidity compared to male background population controls, and the socioeconomic status was inferior on outcome parameters such as education and long-term income.

What is known already: 46,XX DSD males are rare and estimates of prevalence and incidence are limited. An increased morbidity and mortality as well as a negatively affected socioeconomic status are described in males with Klinefelter Syndrome. However, this has never been systematically studied in 46,XX DSD males.

Study design, size, duration: In this nationwide registry study including 44 males with a verified diagnosis of 46,XX DSD we aimed to estimate incidence, prevalence and diagnostic delay. Further, we aimed to study morbidity, mortality and socioeconomic outcome parameters using the Danish registries. The socioeconomic outcome parameters were education, income, retirement, parenthood and cohabitation. 46,XX DSD males were born during 1908-2012 and follow-up started at birth or at start of registration and ended in 2014.

Participants/materials, setting, methods: Potential cases (n = 69) were identified in the Danish Cytogenetic Central Registry and the diagnosis was verified by medical record evaluation (n = 44). A randomly selected age-matched control group of 100 males and 100 females per case was identified by Statistics Denmark.

Main results and the role of chance: Among newborn males the prevalence of diagnosed 46,XX DSD males was 3.5-4.7 per 100 000. Median age at diagnosis was 17.0 years (range: 0.0-62.8). Overall morbidity was increased compared to male controls (hazard ratio [HR] = 2.4, 95% CI: 1.8-3.3) but not when excluding endocrine and urogenital diseases as well as congenital malformations (HR = 1.2, 95% CI: 0.8-1.6). Mortality was not increased (HR = 0.6, 95% CI: 0.2-2.5) compared to male controls. 46,XX DSD males had poorer education (HR = 0.1, 95% CI: 0.0-0.9) and fewer fatherhoods (HR = 0.4, 95% CI: 0.2-0.7) than male controls, and their income was reduced for the following age groups; 45-49 years: odds ratio [OR] = 0.4 (95% CI: 0.2-0.7); 50-54 years: OR = 0.1 (95% CI: 0.0-0.6).

Limitations, reasons for caution: The study cohort is rather small, although it is large in comparison to other studies on 46,XX DSD males. Some 46,XX DSD males may have been excluded from the study owing to lack of data in medical records, making the diagnosis impossible to verify. As in all epidemiologic studies a risk of misclassification must be considered when interpreting the study results, and as the study included diagnosed 46,XX DSD males only, conclusions cannot be extended to non-diagnosed 46,XX DSD males.

Wider implications of the findings: This study provides a new insight into trajectory of health and socioeconomic status of 46,XX DSD males.

Study funding/competing interest(s): This study was funded by research grants from the Health Research Fund of Central Denmark Region, the A.P. Møller Foundation 'Fonden til Laegevidenskabens Fremme', the Lundbeck Foundation and the Novo Nordisk Foundation (NNF13OC0003234 and NNF15OC0016474). The authors have nothing to declare.

Trial registration number: N/A.