安氏Ⅲ类错（牙合）的遗传流行病学研究

Genetic epidemiology of Class Ⅲ malocclusion

目的本文通过对安氏Ⅲ类错(牙合)的家庭聚集性、遗传度及遗传方式的研究,探讨遗传因素在安氏Ⅲ类错(牙合)发生中的地位和作用.方法采用遗传流行病学病例对照的研究方法,对195个安氏Ⅲ类错(牙合)先证家系和208个对照家系进行调查,比较其一级亲属患病率,以二项分布(p+q)n的数学模型及x2检验判定家庭聚集性.以Falconer回归法进行遗传度的估算.结果安氏Ⅲ类错(牙合)先证组一级亲属患病率为27.83%,与对照组8.09%相比,统计学上差异具有显著性.二项分布显示,先证组实际频数大于二项分布的理论频数,说明其具有家庭聚集性.一级亲属遗传度为80.85%,其中男性遗传度为90.79%,高于女性遗传度(71.08%).结论安氏Ⅲ类错(牙合)的发生具有明显的家庭聚集性,属于多基因遗传模式.其一级亲属遗传度为80.85%,遗传倾向有明显的性别差异.遗传因素在其发病中起重要作用,尤其对男性作用更为明显.

Objective To explore the role of genetic factor in Class Ⅲ malocclusion. Methods 403 pedigrees, including 195 Class Ⅲ malocclusion pedigrees and 208 control pedigrees, were investigated in Harbin area. Familial aggregation was evaluated by binominal distribution analysis. Falconer regression method was applied. Results The prevalence rate of Class Ⅲ malocclusion in first-degree relatives was 27. 83%, significantly higher than that of control pedigrees （8.09%）. Results from binominal distribution analysis showed that actual frequency of Class Ⅲ cases were significantly higher than that of theoretical frequency, which indicated that there was significant familial aggregation in the occurrence of Class Ⅲ malocclusion. The heritability of Class Ill malocclusion in first-degree relatives was 80. 85% （90. 79% in male and 71.08% in female）. Conclusions Class Ⅲ malocclusion showed significantly familial aggregation. Genetic factors play an important role in the incidence of Class Ⅲ malocclusion.