Cerebral infarction in a teenager with persistent hyperhomocysteinemia

Cerebral infarction in children in the absence of underlying diseases is rare, and its causes are complex. We present the case of a 14-year-old boy who had experienced left limb weakness and slurred speech for 5 days. Magnetic resonance imaging revealed cerebral infarction in the right side of the brainstem and right cerebellar hemisphere, along with multiple lacunar cerebral infarctions in the bilateral occipital lobes and right centrum semiovale. He was diagnosed with cerebral infarction due to hyperhomocysteinemia and treated with anticoagulants. However, although his symptoms resolved, homocysteine levels remained elevated after 3 months. Genetic testing identified an MTHFR mutation, leading to a modified treatment regimen that included betaine, riboflavin, pyridoxine, folate, and hydroxocobalamin. Following 3 months of this revised regimen, the patient had made a full recovery, with normalized homocysteine levels. Hyperhomocysteinemia caused by MTHFR mutations should be considered in young patients with unexplained cerebral infarction. Supplementation with betaine, riboflavin, pyridoxine, folate, and hydroxocobalamin was established to be beneficial in reducing homocysteine levels.