The aims of the present study were to investigate the genetic prevalence and genetic pattern of Chinese young adults with primary nocturnal enuresis (PNE).

A total of 20,345 university students (aged 17-21 year 6,583 boys and 13,762 girls) from 23 provinces and 368 cities in mainland China were included. The survey was conducted using an anonymous questionnaire to collect the information：①gender, date of birth, inhabitation; ②whether bedwetting had continued from 5 years old until currently; ③ PNE frequency; ④PNE family history; ⑤ ease of waking at night; ⑥UTI occurrence; ⑦frequency, urgency and UI during the daytime. The PNE criterion in this study was when children over 5 years of age have at least one enuresis episode per month, lasting at least 3 months. The exclusion criteria were obvious organic diseases, such as lower bladder urinary tract obstruction, neurological diseases, and incomplete questionnaires.

A total of 22,500 students were investigated, 21,082 questionnaires were collected, and 20,345(89.3%) qualified for statistical analysis. 239 young adults (88 boys and 151 girls) with PNE were identified. The prevalence was 1.3% in male and 1.1% in female. 33.89% (81 cases) had positive family history, and the positive rates of male and female were 32.95% (29/88) and 34.43% (52/151), respectively, and there was no significant difference between males and females (P > 0.05), excluding sex chromosome inheritance. Including 24.69% of fathers, 20.99% of mothers, 4.94%of both parents, 27.16% of the siblings and 22.22% of grandfathers or (and) mothers. Among them, 41 (17.15%) families were autosomal dominant inheritance, 22 (9.21%) families were autosomal recessive inheritance, and 176 (73.64%) families with PNE were sporadic. The prevalence of UTI, severe PNE and daytime voiding symptoms (frequency, urgency and UI) in patients with family history of enuresis were significantly higher than those without family history (2=212.218, 7.994, 5.033, 5.320, 6.920, P < 0.05). However, there was no significant difference in the prevalence of sex, residence and sleep arousal disorder between the two groups (p > 0.05).

In the present study, 239 adolescents with PNE were identified. The prevalence was 1.3% in male and 1.1% in female. Of which 81 cases had positive family history, and the positive rates of male and female were 32.95% and 34.43%, there was no significant difference between them, excluding sex chromosome inheritance. A total of 17.15% families were autosomal dominant inheritance, 9.21% families were autosomal recessive inheritance, and 73.64% families with PNE were sporadic.[1] The results indicate that all modes of inheritance for PNE can occur in different families. In this study, one third of young adults have a family history PNE; indicating that heredity is a prominent factor in young adults; unfortunately, hereditary factors are not easy to change. It was further indicated that children with a family history of PNE were less likely to be relieved with increasing age and will continue to experience PNE through adolescence and adulthood; therefore, early interventions are highly recommended. This study found that the prevalence of abnormal daytime urination and severe PNE in patients with positive family history of PNE was significantly higher than that in patients without. It is suggested that patients with positive family history of PNE are often characterized by severe PNE and are prone to abnormal daytime urination. Special attention and early treatment should be given to patients with positive family history of PNE.

PNE has obvious family aggregation and a variety of genetic patterns coexist. Early treatment should be given to patients with positive family history of PNE.

Wang QW, Wen JG, Zhang RL, et al. Family and segregation studies: 411 Chinese children with primary nocturnal enuresis. Paediatric Int 2007; 49:618–22.