**5. Primary angle-closure glaucoma (PACG)**

PACG also involves progressive and irreversible degeneration of the optic nerve with grad‐ ual visual field loss. It is estimated that in Saudi Arabia 40% of glaucoma patients belong to PACG. Although hereditary component for PACG exists, causative genes have not been identified except occasional differences in the frequency of polymorphisms in some genes. For instance, variations in Best disease (BEST1), hepatocyte growth factor (HGF), matrix metalloproteinase - 9 (MMP-9) and methylenetetrahydrofolate reductase (MTHFR) genes have been reported [28]. However, some of these results were not extended to other popula‐ tions.
