This variant was seen as a compound heterozygote (with the causative 2299delG) in a Caucasian individual with Usher syndrome type IIa (1 out of 31 patients screened). It was also seen in 1/100 control chromosomes. The variant is found in the N-terminus of the protein, but it is unclear what effect it could have on function.
This variant was seen heterozygously in one out of 36 families screened and not in 50 control individuals.
The authors screened patients and controls and find this variant at similar frequencies in both groups: 4/275 patients and 2/95 controls (all heterozygous). They conclude it is a non-pathogenic polymorphism.
The authors note that this mutation is rare but equally frequent in patients and controls. They conclude that it is non-pathogenic, reversing their earlier report of pathogenicity.