[Adult-onset Hartnup disease presenting with neuropsychiatric symptoms but without skin lesions].

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)