EOG in a large family with hereditary macular degeneration. (Best's vitelliform macular dystrophy) identification of gene carriers.

A total of 128 descendants from one large family with a history of hereditary macular degeneration (HMD) were examined with EOG. Of these, 42 were affected patients, 48 were healthy offsprings to affected parents, and 38 were normal controls. Affected subjects had a light peak/dark trough ratio smaller than 1.40. In the group of offspring of affected parents the Lp/DT ratios showed a bimodal distribution dividing the group into two parts, one with values less than 1.40 and another with values larger than 1.70. Thus carriers of the HMD gene can apparently be identified by use of EOG. The affected subjects and the carriers had a lower base value of the standing potential than the controls.