Although the cause of autism is not yet known, it is thought that this disorder is related to genetic and environmental factors. Cytogenetic anomalies and single gene disorders are responsible for less than 10% of all autistic cases. We herein present a case of autism, the etiology of which is metabolic cytopathy.

BA is a 25 years-old male and is the only child in the family. He was diagnosed by many doctors as having ‘Attention Deficit Hyperactivity Disorder’ (ADHD) until he was thirteen. The patient has been under our follow-up for the last 12 years since he was 13 and the diagnosis was corrected to Autistic Disorder at his first visit. During all this period, the patient gained 25 kg and he showed no neurological symptoms. On the cranial magnetic resonance imaging, bilateral lesions in the putamen, thalamus, partial lesions in the caudate heads, cerebellar white matter and the dentate nucleus were detected, which were hypointense at T1, hyperintense at T2 and iso-hypointense at FLAIR. The patient underwent evaluation by neurologists, biochemists and radiologists, but no etiologic factors could be detected. The present condition was considered to bean unconfirmed ‘metabolic cytopathy’.

Should autistic cases be stratified into subgroups according to the underlying genetic risks, it may even be possible to define a special subgroup which would cover the metabolic cytopathy present in our case. In conclusion, it is possible that autism due to metabolic causes is of genetic origin; however, this tendency should be detected by a molecular approach.