OCULAR FINDINGS IN A FAMILY WITH AUTOSOMAL-DOMINANT RETINITIS-PIGMENTOSA AND A FRAMESHIFT MUTATION ALTERING THE CARBOXYL-TERMINAL SEQUENCE OF RHODOPSIN

A family is described in which an 8 base pair deletion (nucleotides 52 52-5259, codons 341-343) of the rhodopsin gene cosegregates with autos omal dominant retinitis pigmentosa (adRP). The deletion results in a s hift in the reading frame, causing a rhodopsin molecule extended by on e residue and substantially altered at the carboxyl terminus. Phenotyp ic expression is relatively mild. In affected members, night blindness did not occur before the age of 16, and late onset of visual field lo ss was consistently reported. Even older individuals (59 and 76 years) had preserved central islands in the visual field; a younger female p atient had normal visual fields until the age of 34. ERG and psychophy sical tests showed well preserved cone function at stages of virtually abolished rod function. Phenotypic differences and similarities betwe en this form of adRP and others associated with mutations at the carbo xyl terminus of the rhodopsin molecule are discussed. The cause of RP by mutations in this region remains to be clarified.