Methylmalonicaciduria with homocystinuria, cbl F

Methylmalonicaciduria with homocystinuria, cblF
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Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Developmental delay, failure to thrive, metabolic acidosis
Complications	N/A
Onset	Infancy
Duration	N/A
Types	N/A
Causes	Mutations in the LMBRD1 gene
Risks	N/A
Diagnosis	Genetic testing, biochemical analysis
Differential diagnosis	N/A
Prevention	N/A
Treatment	Vitamin B12 supplementation, dietary management
Medication	N/A
Prognosis	Variable
Frequency	N/A
Deaths	N/A

Methylmalonicaciduria with homocystinuria, cblF is a rare inborn error of metabolism that affects the body's ability to process certain amino acids and lipids. It is classified as a type of methylmalonic acidemia and homocystinuria, specifically the cblF type, which is caused by mutations in the LMBRD1 gene.

Pathophysiology

Methylmalonicaciduria with homocystinuria, cblF, results from a defect in the intracellular processing of vitamin B12 (cobalamin). The LMBRD1 gene encodes a protein that is essential for the transport of cobalamin into the cytoplasm, where it is converted into its active forms, adenosylcobalamin and methylcobalamin. These active forms are crucial cofactors for the enzymes methylmalonyl-CoA mutase and methionine synthase, respectively. A deficiency in these cofactors leads to the accumulation of methylmalonic acid and homocysteine in the blood, causing the clinical manifestations of the disorder.

Clinical Presentation

Patients with methylmalonicaciduria with homocystinuria, cblF, typically present in infancy with symptoms such as developmental delay, failure to thrive, and metabolic acidosis. Other symptoms may include hypotonia, seizures, and megaloblastic anemia. The accumulation of toxic metabolites can lead to neurological damage and other systemic complications.

Diagnosis

Diagnosis is based on clinical presentation, biochemical analysis, and genetic testing. Elevated levels of methylmalonic acid and homocysteine in the blood and urine are indicative of the disorder. Genetic testing can confirm the diagnosis by identifying mutations in the LMBRD1 gene.

Treatment

Treatment involves the administration of high doses of hydroxocobalamin, a form of vitamin B12, which can bypass the defective transport mechanism. Dietary management to restrict certain amino acids may also be necessary. Early diagnosis and treatment are crucial to prevent irreversible neurological damage and improve outcomes.

Prognosis

The prognosis for individuals with methylmalonicaciduria with homocystinuria, cblF, varies depending on the severity of the condition and the timeliness of treatment. With appropriate management, some patients may lead relatively normal lives, while others may experience significant developmental and neurological challenges.

Also see

• Methylmalonic acidemia
• Homocystinuria
• Inborn errors of metabolism
• Vitamin B12 deficiency