Genetic Analysis of Consanguineous Pakistani Families with Congenital Stationary Night Blindness.

INTRODUCTION

Congenital stationary night blindness (CSNB) is a rare, largely nonprogressive, inherited retinal disorder that can be clinically classified on the basis of fundus and electroretinogram abnormalities.

METHODS

We analyzed four large consanguineous families from the Southern Punjab region of Pakistan including multiple individuals affected with CSNB. Exome sequencing was performed in probands of all four families; Sanger sequencing was performed in additional members to test co-segregation of the variants identified.

RESULTS

We identified two novel and likely pathogenic variants in two pedigrees, namely, NM_002905.4:c.668A>C (p.Gln223Pro) in RDH5 and NM_022567.2:c.908del (p.Gly303ValfsTer45) in NYX. In the two other families, the variants NM_002905.4:c.319G>C (p.Gly107Arg) in RDH5 and NM_000541.5:c.874C>T (p.Arg292Ter) in SAG were identified. These latter mutations have been reported previously, but not in the Pakistani population.

CONCLUSIONS

Our findings expand the mutational spectrum of CSNB, in particular within the population of Southern Punjab.