Evoked potentials were studied in four cases with Angelman syndrome. Chromosome
15ql1-13 deletion was proved in two cases and paternal uniparental disomy was proved in
the rest. Prolonged photo-evoked eyelid microvibration latencies were noted in all four，
while visual evoked potential latencies remained within normal limits in three of four.
Interpeak latencies of wave I to wave V in auditory brainstem response were prolonged
in two of four. Short latency somatosensory evoked potential was examined in two cases
and prolonged interpeak latency of wave P3 to wave N1 was noted in one case. Brink
reflex was examined in one case and prolonged R2 latency was noted. These findings
suggest that the brainstem is disturbed in cases with Angelman syndrome.