Hartnup disease is an inborn abnormality of renal and intestinal transport involving the
neutral amino acids. Intermittent
pellagra-like
rash, attacks of
cerebellar ataxia and psychiatric disturbance are characteristic symptoms of this disease. We described here a patient with adult-onset
Hartnup disease who presented unique neuropsychiatric symptoms but no dermatologic symptoms, and reported features of
amino acids transport in this patient and his family. The patient, a man aged 37 years, was referred to us because of lasting daytime
bruxism. He is the second child of healthy parents who are first cousin; his elder brother who has been mentally retarded became bed-ridden and died at 32 years of age. His younger brother is completely healthy. Although the patient's development in infancy has been slightly retarded, he completed compulsory 9-year education. At 29 years of age, he experienced episodes of
diplopia, ataxic gait and
insomnia, and at 33 years of age, of transient stupor. There had been no history of photosensitivity or
dermatitis. On neurological examination, there were trunkal
ataxia, increased muscular tone and decreased mental activity besides
bruxism. These symptoms remained unchanged despite of several medications including
trihexyphenidyl,
diazepam, halloperidol,
tiapride and
sulpiride. Two months later, the patient became stuporous;
bruxism and hypertonicity became exaggerated. Myerson's sign, sucking reflex and grasp reflex in both hand appeared. There was no dermal lesion. A cranial computed tomography revealed a small calcification in the right frontal subcortical region and a single photon emission tomography indicated possible bifrontal hypoperfusion. Electroencephalograms demonstrated non-specific slowing. Somatosensory evoked potentials and nerve conduction velocities were normal. There were constant indicanuria and amino-aciduria.(ABSTRACT TRUNCATED AT 250 WORDS)