Plasma gamma-aminobutyric acid (GABA) levels were measured in 14
subjects with Prader-Willi syndrome, 9 subjects with Angelman syndrome, and
matched control subjects. Mean levels in both patient groups were 2 to 3
times higher than in nonretarded moderately obese or retarded nonobese
control subjects. Levels in each patient group differed significantly from
both control groups. Neither the two patient groups nor the two control
groups differed. GABA levels seemed unrelated to genetic status (chromosome
15 deletion or disomy). These preliminary findings of elevated plasma GABA
levels possibly represent a compensatory increase in presynaptic GABA
release in response to hyposensitivity of a subset of GABA receptors and
could produce increased postsynaptic activation of other normal GABA
receptor subtypes, resulting in complex alterations of GABAergic function
throughout the brain.Abstract Teaser