Context and objective: Constitutional delay of growth and puberty (CDGP), more commonly observed in boys than in girls, often has a familial background. We characterized the occurrence of CDGP in relatives of CDGP patients to elucidate the mechanisms influencing timing of puberty.

Participants and design: We identified 492 subjects with CDGP from hospital records of two pediatric clinics in Finland; 95 male and 29 female subjects and their first-degree relatives participated. In family-members, CDGP was defined by use of growth charts (growth spurt taking place 2 SDs beyond the mean). One-third of the families was expanded to include also second-degree relatives with an interview-based assessment of pubertal timing.

Results: Of male, 80%, and of female probands, 75%, had first-degree relatives with CDGP. Of all probands, 45% had one (unilineal families) and 32%, two parents affected. In 2% of the families only siblings were affected. The prevalence of CDGP in male first-degree relatives was only slightly higher than in female relatives: 79 of 148 (53%) vs. 64 of 164 (39%) (P = 0.01); male-to-female-ratio 1.2:1. In 74% (17 of 23) of extended unilineal pedigrees, the inheritance pattern of CDGP was consistent with autosomal dominant inheritance.

Conclusions: CDGP clusters in families. Although its inheritance likely is complex, some predisposing genetic factors may have a dominant effect. CDGP was almost as common in male and female relatives of the CDGP subjects seen at specialist care, challenging the view of a marked overall male preponderance of CDGP.