Retinitis pigmentosa

Retinitis pigmentosa (RP) is the most common type of inherited
retinal degenerative disorder. Like many other eye conditions it
is genetically heterogeneous, with autosomal dominant (25%),
autosomal recessive (50%), and X linked (25%) cases. In
isolated cases the mode of inheritance cannot be determined
from clinical findings, except that X linked inheritance can be
identified if female relatives have pigmentary abnormalities and
an abnormal electroretinogram. Linkage studies have identified
three gene loci for X linked retinitis pigmentosa and mutations
in the rhodopsin and peripherin genes occur in a significant
proportion of dominant cases.