Camilleri S, Lewis C M, McDonald F
Department of Orthodontics, Kings College London, Dental Institute, Guy's Tower, London, UK.
J Dent Res. 2008 Jun;87(6):580-3. doi: 10.1177/154405910808700606.
The etiology of ectopic canines is controversial, with opinion divided as to a genetic or environmental mechanism. This study addressed the hypothesis that genetic factors play a role in the etiology of ectopic maxillary canines. Sixty-three probands were identified, and information on the dental status of 395 relatives was determined. Pedigrees were constructed and the Relative Risk calculated. Complex segregation analysis was carried out by means of the Pedigree Analysis Package. The best mathematical model obtained was a single dominant gene with autosomal transmission, incomplete penetrance, and highly variable expression. Only two of seven pairs of monozygotic twins were concordant for ectopic canines. This is consistent with environmental or epigenetic variables affecting the phenotype. The low concordance rate is consistent with the low penetrance determined by the segregation analysis and further supports the existence of environmental factors.
异位犬齿的病因存在争议，对于其是由遗传还是环境机制引起，观点不一。本研究探讨了遗传因素在异位上颌犬齿病因中起作用这一假说。确定了63名先证者，并确定了395名亲属的牙齿状况信息。构建了家系并计算了相对风险。通过家系分析软件包进行复杂分离分析。获得的最佳数学模型是一个具有常染色体显性遗传、不完全外显率和高度可变表达的单显性基因。七对同卵双胞胎中只有两对异位犬齿情况一致。这与影响表型的环境或表观遗传变量相符。低一致率与分离分析确定的低外显率一致，并进一步支持环境因素的存在。
