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 Ux 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.