Genetic Heritability of a Shallow Anterior Chamber in Chinese Families with Primary Angle Closure Glaucoma

Purpose:To explore the genetic heritability of a shallow anterior chamber (AC) in families with primary angle closure glaucoma (PACG) and to provide a theoretical basis for the identification of candidate genes responsible for PACG. Methods: Genetic analyses included familial and segregation analysis, tests for multifactorial inheritance and thresholds. The data was used to determine heritability. The relative risk rate and the possible genetic pattern of a shallow AC were examined in 114 pedigrees with PACG probands. Results: The estimated heritability value of a familial shallow AC was 92.6% +/- 5.9%; the relative risk rate of a shallow AC was 7.91. The rate of affected female siblings to affected males was 2.87:1, which was statistically higher than that of affected male siblings (chi(2) = 9.75, P < 0.01). In two different mating types, the segregation ratios of U x U (parents unaffected) and U x A (one parent affected) were 0.11 and 0.426 respectively. The result of segregation analyses suggested that the genetic pattern of U x U did not possess the characteristics of a monogenetic model and the genetic pattern of U x A exhibited autosomal dominant inheritance traits. Conclusions: We have shown that there is a higher heritability and a higher relative risk rate in the Chinese population of familial shallow ACs. The inheritance of a shallow AC may be a genetically heterogeneous trait and influenced by gender with autosomal dominant inheritance in subgroups. These results provide a theoretical basis for the identification of candidate genes responsible for Chinese PACG.