As with any other protein, rhodopsin has a few mutations. The most common and well studied is retinal pigmentosa. Retinal pigmentosa is chareacterised by the loss of function followed by slow progressive degeneration of the peripheral retina. There are a lot of various reasons for this disorder. The most common ones occur as one of 13 point mutations in 12 amino acid positions in opsin and can be classified into two subclasses.
Class 1:
Phe 45--> Leu
Glu 314 --> stop codon
Pro 347--> Leu
The mutations from this class resemble the wild type rhodopsin in yield, regeneratability, and plasma membrane location.
Class 2:
Thr17--> Met
Pro 23--> His
Thr 58--> Arg
Val 87--> Asp
Gly 89--> Asp
Gly 106--> Trp
Arg 135--> Leu
Arg 135-->Trp
Try 178--> Cys
Arg 190--> Gly
The mutations from this class have low opsin yield, variability in regeneration or no regeneration at all, is found mostly in the endoplasmic reticulum indicating inefficient transportation to the plasma membrane.
Another mutation is Stationary night blindness--This mutation is caused by the lack of enough Vitamin A to make the chromophore and regenerate rhodopsin. this causes a delay in the regeneration of rhodopsin because there is not availible 11-cis retinal to bind to free opsin. This is deficiency causes an increase in rod threshold. This implies that a larger amount of photons must be absorbed for the rhodopsin retinal component to change conformation. Thus, in low light areas such as during the night, a person with the condition will not be able to see because the signal is not being relayed to the brain. Hence, the name night blindness.