Deletion mapping of a retinal cone‐rod dystrophy: Assignment to 18q211

Abstract
Deletion of 18q211 was observed in a mentally retarded young man with electrophysiologically demonstrated cone‐rod dystrophy, present since childhood. He had hypogonadism and a central postsynaptic hearing impairment. This is the first case of a chromosome deletion in a patient with a cone‐rod dystrophy. Three patients with more distal deletions on chromosome 18 did not present retinal dystrophies. We suggest that one of the loci for cone‐rod dystrophy may be located on chromosome 18 at q211‐213. Reports of similar findings will be necessary for confirmation of this assumption.