Patterns of inheritance of constitutional delay of growth and puberty in families of adolescent girls and boys referred to specialist pediatric care.

CONTEXT AND
OBJECTIVE: Constitutional delay of growth and puberty (CDGP), more commonly observed in boys than 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 sd 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 males, 80%, and of female probands, 75% had first-degree relatives with CDGP. Of all probands, 45% had one parent (unilineal families) and 32% had 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%), respectively (P=0.01); male to female ratio was 1.2:1. In 74% of extended unilineal pedigrees (17 of 23), 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.