Visual evoked potential evidence of albino-like chiasmal misrouting in a patient with Angelman syndrome with no ocular features of albinism.

An 8-month-old boy with global developmental delay, including visual and hearing inattention, was examined in the ophthalmic clinic. Monocular flash visual evoked potentials demonstrated a crossed asymmetry in scalp distribution, a feature considered to be pathognomic of albinism. Remarkably a foveal reflex was noted in each eye and this patient did not have nystagmus, iris transillumination, nor conspicuously pale fundi. The optic discs appeared normal. He was noted to have very fair skin and hair, with a small head and flat occiput. Cytogenetic studies demonstrated a microdeletion of the maternal chromosome 15q11-q13, and he was diagnosed with Angelman syndrome.