This 18 year old man was hypotonic as a baby and developmental delay with reduced cognitive ability was evident by age 3. Night blindness and reduced peripheral vision were evident in the first decade of life and reduction of visual acuity began about age 11. He has a low neutrophil count but does not experience frequent infections.

The clinical features supporting the diagnosis of Cohen syndrome in this patient include: bone-spicule-like pigmentation and narrowed arterioles on ophthalmoscopy; photoreceptor loss on OCT; developmental delay; stable reduced cognition; long tapered fingers; a shortened philtrum; a gregarious personality; a low neutrophil count; a similarly affected sister; and, normally sighted parents.