Parkinsonian-Like Locomotor Impairment in A Child With A Putative Defect of Dopamine D2 Receptors

Abstract

A four year old girl presented with Parkinsonian symptoms suggestive of cerebral dopamine deficiency - profound hypokinesia, bradykinesia, tremor of the limbs and tongue, an expressionless face, drooling and trunkal hypotonia. Brain MRI and EEG were normal. No clinical improvement on therapy with L-DOPA, CSF concentrations of homovanillic acid, reflecting the overall flow through the dopamine pathway was not reduced but highly increased instead with 2050 nmol/l (normal 400-650). Its precursor, 3,4-dihydroxyphenylacetic acid was also found elevated at 22 nmol/l (normal < 5). CSF concentrations of phenylalanine, tyrosine, L-DOPA, 3-ortho-methyl-Dopa, vanillactic acid, 3-methoxytyramine, 3-methoxy-4-hydroxyphenylethyleneglycol, 5-hydroxytryptophane, and 5-hydroxyindoleacetic acid were all normal.