night blindness—congenital stationary—1D 

OPHTHALMOLOGY

Definition An autosomal recessive form (OMIM:613830) of congenital stationary night blindness*, which is characterised by a Riggs type of electroretinogram (proportionally reduced a- and b-waves). Patients have normal range of visual acuity without myopia or nystagmus.  

*A non-progressive retinal disorder characterised by impaired night vision.

Molecular pathology Defects of SLC24A1, which encodes a potassium-dependent sodium/calcium exchanger that is a critical component of the visual transduction cascade, controlling the calcium concentration of outer segments during light and darkness, acting on retinal rod and cone photoreceptors, cause congenital stationary night blindness 1D. 

References http://www.genecards.org/cgi-bin/carddisp.pl?gene=SLC24A1

http://www.uniprot.org/uniprot/O60721