Objective: To investigate the genetic mode of nasal polyp and the effect of genetic factor on occurrence of the disease.
Methods: A genetic epidemiological case-control study including 280 pedigrees (120 nasal polyp cases and 160 controls) was conducted. The segregation ratio and the heritability of nasal polyp were respectively estimated by the Li-Mantel-Gart method and the Falconer method.
Results: The segregation ratio was 0.124 (95% CI 0.081-0.167), significantly lower than 0.25, which showed that nasal polyp did not possess the characteristics of monogenetic model. The prevalence rate of first-degree and second-degree relatives in cases were 8.571% and 3.086% respectively, which were significantly different (X2 = 24.851, P < 0.01) and were higher than that noticed 1.376% and 1.141% in controls (X2 = 33.547 and 14.274, all P < 0.01). The heritability of the first-degree and second-degree relatives of nasal polyp was 64.488% and 61.947%. Among the first-degree relatives of nasal polyp probands, the heritability of the adult group and the children group were respectively 60.735% and 74.598% (the difference was significant, X2 = 4.504, P < 0.05). The heritability of the first-occurred group was 62.839% and the recurred group was 74.304% (the difference was significant, X2 = 4.105, P < 0.05).
Conclusions: This study indicated that the genetic model of nasal polyp belonged to polygenetic and the genetic factors played an important role in the occurrence of nasal polyp, especially for young or recurred patients.