A 9-year-old boy presented with abnormal behavior for six months. He had unprovoked aggressive behavior, and occasional self-inflicting behavior. He also had decreased appetite, anhedonia, apathy, reduced sleep, low energy, motivation, and poor interaction with parents and peers. He had mild cognitive impairment, below-average intelligence, moderate depression, and mild psychotic symptoms on assessment with appropriate scales. He had macrocytic anemia with low vitamin B12 levels. Nextgeneration sequencing revealed a novel mutation of Leu116Pro of the MMACHC gene, suggestive of combined methylmalonic aciduria and homocystinuria (cblC type). Timely initiation of therapy can change the long-term neurological outcome.
Keywords: Combined methylmalonic aciduria and homocystinuria; Neurometabolic disorder; Neuropsychiatric symptoms; Novel mutation.
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