Reduced Frequency of Biological and Increased Frequency of Adopted Children in Males With 21-Hydroxylase Deficiency: A Swedish Population-Based National Cohort Study

Context: Fertility in males with 21-hydroxylase deficiency (21OHD) is unclear. Objective: Study fertility outcome in males with congenital adrenal hyperplasia. Design, Setting, and Participants: Males >= 15 years old with 21OHD (n = 221) were compared with controls matched for sex and year and place of birth (n = 22,024). Data were derived by linking national population-based registers. Subgroup analyses were performed regarding phenotype [salt-wasting (SW), simple virilizing (SV), and nonclassic (NC)] and CYP21A2 genotype (null, I2 splice, I172N, and P30L) and stratified by the introduction of neonatal screening. Main Outcome Measures: Number of biological and adopted children. Results: Males with 21OHD were less likely to be fathers of biological children [odds ratio (OR), 0.5; 95% confidence interval (CI), 0.4 to 0.7; after adjusting for socioeconomic characteristics: OR, 0.4; 95% CI, 0.2 to 0.5]. This was true for SW, SV, I2 splice, and I172N, but not for NC, null, and P30L groups (all adjusted). Among patients born before the neonatal screening introduction, fewer were fathers (adjusted OR, 0.3; 95% CI, 0.2 to 0.5), but this normalized in those born afterward. Adoption was more common in the 21OHD males (OR, 2.9; 95% CI, 1.0 to 7.9) and the SV and I172N subgroups. Age at becoming a father, marriage, region of residence, and education were similar, but fewer patients had high incomes. NC and I172N groups had, however, higher academic degrees and NC patients were more often married, whereas SW and I2 splice patients were more often divorced. Conclusions: 21OHD was associated with a reduced frequency of biological children and an increased frequency of adopted children, suggesting impaired fertility, although some subgroups had normal fertility.