Clinical and genetic findings of the six patients.

The upper three patients show a complete absence of Kv8.2 due to large deletions or protein truncating mutations of KCNV2 and so represent the NOP group. The lower three patients represent the ALP group with altered Kv8.2 subunits due to KCNV2 mutations. The BD27.I and BD27.II are brother and sister of one family, so are CHRO8.I and CHRO.II of another family. Each case shows an autosomal recessive inheritance. A considerable difference between the NOP and ALP group cannot be observed. However, there is a tendency for a slightly better visual acuity (VA) and higher myopia in the ALP group (lower three patients). Interestingly, night blindness, subjective disease progression and a severe protanomaly are present in the only homozygous patient (RCD307), while other patients reveal unchanged visual function over disease duration, no night blindness and color disturbances consistent with a rod dominated function. (Patients marked with * have been published in Wissinger et al. [19]).