1.2 Study characteristics for SSNST

1.2 Study characteristics for SSNS

The search yielded 11 references reporting the association of ACE I/D gene polymorphism and the onset of SSNS. One study [29] was excluded because the distribution of ACE I/D gene polymorphism was not in detail. Furthermore, one report [6] was conducted in Caucasians and two [25], [30] were in Africans, and these were excluded from our investigation for the relationship between ACE I/D gene polymorphism and SSNS risk. Seven studies [4], [8], [14], [26], [27], [28], [31] were identified for the analysis of the association between ACE I/D gene polymorphism and SSNS susceptibility in our final review (Table 2). Interestingly, all the included studies were performed in children. Five studies were published in English and two [28], [31] in Chinese. Those seven investigations contained 356 case series and 787 controls. The average distribution frequency of ACE D allele in children with SSNS was 50.97%, and the average frequency in controls was 46.68%. The average distribution frequency of D allele in cases was similar with that in control group (SSNS/control = 1.09).