ERG testing and directed genetic testing of CRB1 and RS1 for the family members confirmed CRB1-retinopathy in the proband, X-linked retinoschisis in the younger brother (hemizygous RS1 mutation), and X-linked retinoschisis in the older sister (homozygous RS1 mutation).
The fact that this occurred bilaterally and in both sisters supports the concept of relative vessel wall incompetence as part of CRB1-related retinopathy.
We evaluated the role of Crumbs homolog 1 (CRB1) in autosomal recessive (AR) retinal diseases in the Israeli and Palestinian populations using homozygosity mapping.
However, there is no clear genotype-phenotype correlation for CRB1 mutations, which suggests that other components of the CRB complex may influence the severity of retinal disease.