Teaching NeuroImages: White matter hypomyelination and progressive calcifications in cerebral folate deficiency

Cerebral folate transport deficiency is caused by homozygous or compound heterozygous mutations of the FOLR1 gene.(1) Recently, we found a homozygous FOLR1 mutation (NM_016725.2: c.562C>G p.[Leu188Val]) in a 2.5-year-old boy with febrile and nonfebrile status epilepticus, progressive ataxia, and progressive MRI abnormalities. Until the diagnosis was made, serial MRI had been performed (figure). CSF analysis (5-methyltetrahydrofolate <2 nmol/L, normal >40 nmol/L) and magnetic resonance spectroscopy showing a low choline peak validated the pathogenicity of our findings.(2