Dimethylglycine dehydrogenase deficiency

Dimethylglycine dehydrogenase deficiency (DMGDH deficiency) is an extremely rare inborn error of metabolism caused by mutations in the DMGDH gene, which encodes the mitochondrial enzyme dimethylglycine dehydrogenase. This enzyme is involved in the choline degradation pathway, specifically catalyzing the conversion of dimethylglycine to sarcosine. When this enzyme is deficient, dimethylglycine accumulates in the blood and urine, leading to a characteristic fish-like body odor. The condition is classified under disorders of amino acid metabolism. The clinical presentation of DMGDH deficiency appears to be relatively mild. The most consistently reported feature is an unusual fish-like body odor due to the accumulation of dimethylglycine. Some patients have been reported with muscle fatigue and elevated serum creatine kinase levels, suggesting possible skeletal muscle involvement. However, the full clinical spectrum remains poorly defined due to the very small number of cases described in the medical literature. There is currently no specific treatment for DMGDH deficiency. Management is primarily supportive and symptomatic. Dietary modifications, particularly restriction of choline intake, may help reduce the accumulation of dimethylglycine and alleviate the associated body odor, though evidence for this approach is limited. Given the rarity of the condition, long-term prognosis and natural history are not well established. Genetic counseling is recommended for affected families.

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