WFS1 and diabetes mellitus: RP was reported in a few cases.20 The genetic basis of the disease is due to mutations in the WFS1 gene, which has been postulated to be an endoplasmic reticulum calcium channel transporter in pancreatic β-cells and neurons.18 Although diabetes and optic atrophy represent the minimal diagnostic criteria, other clinical characteristics include neurodegenerative disease involving the hypothalamus, brain stem, and the cerebellum.