Morphologic studies in a patient with homocystinuria due to 5,10 methylenetetrahydrofolate reductase deficiency

Morphologic studies on a patient with homocystinuria due to 5,10 methylenetetrahydrofolate reductase are described. The arterial lesions were prominent and showed fragmentation of the elastic lamellae. Perivascular demyelination and thrombosis were observed in the brain. Hirano bodies in the cortical neurons and crystalline and lamellar bodies in the Purkinje cells were present. Lipid droplets, giant mitochondria, myelin figures, and membrane bound multivesicular bodies in the hepatocytes were seen. Fragmentation of the Z disks of striated muscle and wrinkling of the glomerular basement membrane were observed. The morphologic lesions observed in this patient were, to some extent, similar to those described in patients with homocystinuria with either cystathionine β synthase or N⁵ methyltetrahydrofolate homocystine methyltransferase deficiency. Furthermore, it is suggested that the pathologic changes observed are probably 'vasculotoxic' in nature.