Family and segregation studies: 411 Chinese children with primary nocturnal enuresis

BACKGROUND: The aim of the present paper was to determine the incidence of primary nocturnal enuresis (PNE) among relatives of Chinese children with PNE, the inheritance pattern, and to identify the characteristics of PNE with positive family history. METHODS: From July 2003 to June 2004, an epidemiological survey on PNE children was carried out by self-administered questionnaires to parents of 5-18-year-old Chinese students in Henan Province, central China. A detailed family history was recorded in order to determine the presence of familial PNE as defined as any close relative with PNE beyond the age of 5 years. RESULTS: The response rate was 88% (10 383/11 799), and 411 children (235 boys and 176 girls) with PNE were identified. A positive family history was found in 94 families (22.87%) of 411 probands with PNE, including 48.94% of fathers, 8.51% of mothers, 6.38% of both parents, 6.38% of the siblings and 29.79% of grandfathers or (and) mothers. Among the probands the ratio of male to female was 1.3:1 excluding sex-linked inheritance. Autosomal dominant inheritance was in 14.60%, and autosomal recessive inheritance was consistent in 1.46% of families. In PNE children with positive family history, the proportion of adolescents, with associated daytime symptoms, marked PNE and seeking professional help were significantly higher than those in PNE children without positive family history. CONCLUSIONS: PNE has a significant family clustering, and all modes of inheritance can occur in different families on the basis of a formal genetic analysis. Those with positive family history often manifest marked PNE, and have daytime symptoms.