BACKGROUND:Cobalamin C disease is the most common inborn error of cobalamin metabolism with an autosomal recessive mode of inheritance and mutations within the MMACHC gene. Clinical features including systemic, hematological, and neurological abnormalities usually occur in the first year of life. Adolescent and adult-onset presentations are rare.
METHODS:We report on the clinical, molecular and imaging features in three patients aged 40, 42 and 42 years at the last follow-up. We will look at these cases together with the eight previously described to delineate clinical and molecular features of the disease in adults.
RESULTS:Mean age at onset of clinical symptoms was 26 years; clinical features included predominant neurological disturbances and thromboembolic complications. White matter abnormalities on brain MRI were sometimes observed. Most patients (8 of 9 patients investigated) were compound heterozygotes for the 271dupA mutation and a missense mutation. Intramuscular or intravenous hydroxycobalamin therapy stopped the progression of the disease and resulted in a better clinical outcome and favorable biological status in 7/9 treated cases, while the two untreated patients died quickly.
CONCLUSIONS:Since cobalamine C disease and related disorders of homocysteine metabolism are treatable conditions, homocysteinemia should be included in the investigations of patients with progressive neurological deterioration, unexplained psychiatric disturbances or recurrent thromboembolic events.
- MMACHC gene
- cobalamin C disease
- white matter abnormalities