OCD and Impulsivity in Late-Onset Isolated Sulfite Oxidase Deficiency
Case report about late onset SUOX deficiency, that was overlooked and the boy had lots of difficulties until age of 16, when the true reason was finally found.
The boy had OCD, seizures, “behavioral disorders”, intellectual disability - everything screams for “he has metabolic disorder!”.
Quote:
“We evaluated a 16-year-old boy due to a phenotype characterized by disruptive, impulse-control and conduct disorders associated with moderate intellectual disability.
He achieved his psychomotor milestones on time and did not show neurological symptoms until 18 months of age when, after a febrile episode, he showed ataxia and subsequently a drowsy state.
He was admitted to the hospital and treated for possible cerebellitis.
Brain CT scan and electroencephalogram (EEG) were normal. He was discharged with the diagnosis of a “post-flu drowsy state.”
After this episode, focal seizures appeared, associated with interictal mid-posterior EEG abnormalities, managed with valproic acid. At the time of our evaluation, he showed moderate intellectual disability (Wechsler Intelligence Scale for Children IV: total IQ 45), stable over the subsequent years, an oppositional defiant disorder, intermittent explosive disorder with hetero-aggression and obsessive-compulsive traits.
The behavioral disorder was the most debilitating aspect and required pharmacological treatment. Neurological examination revealed dysarthria with slurred speech, slight dysmetria and action tremor.
Brain MRI at 9 years showed enlarged cerebrospinal fluid spaces in the cerebellar, hemispheric and vermian regions with inferior vermis hypoplasia, slightly dilated fourth ventricle widely communicating with the cisterna magna and mild hyperintensity of the dentate nuclei (Figure 1).
Neuroradiological follow-up until the age of 15 years did not reveal significant changes.”
Key Takeaway
Always try to test markers of metabolic disorders. In this case, sulfite, S-Sulfonylcysteine, uric acid and purines in urine should have been tested early in life.