Familial transmission risk of infantile glaucoma in Australia

Purpose: Primary infantile glaucoma (PIG) is predominantly inherited as a recessive disease, whereas anterior segment dysgenesis (ASD) is usually dominantly inherited. The purpose of this study was to determine the likelihood of a person who has infantile glaucoma to produce a child who also manifests the disease.

Methods: A retrospective cross-sectional design was utilized. The pedigrees of probands from south-eastern Australia diagnosed with infantile glaucoma since 1980 were reviewed. Cases were subdivided into two groups according to the presence or absence of ASD. Exclusion criteria included incomplete pedigree phenotype information or aphakic glaucoma following congenital cataract surgery. Fisher's exact test was used to compare the parent-offspring phenotype transmission between ASD-associated infantile glaucoma and PIG.

Results: A total of 67 probands were identified; however, three pedigrees were excluded due to incomplete phenotype information. Direct parent-offspring transmission of phenotype was statistically significantly more common in ASD-associated infantile glaucoma (2/8) than in PIG (1/56) pedigrees (p = 0.039).

Conclusions: Although this study reveals that Australian patients with ASD-associated infantile glaucoma are at greater risk of having children with infantile glaucoma than patients with PIG, the number of ASD pedigrees with direct transmission of infantile glaucoma is lower than expected. Based on our population frequency analysis and the results of our study, the risk of PIG, if one parent is affected by PIG and the other is normal, is less than 2%.