Vitamin B12 Unresponsive Methylmalonic Acidemia Type Mut C0342719
A genetic metabolic disorder that does not respond to vitamin B12 therapy. The body cannot break down certain amino acids, causing harmful substance buildup. Treatment involves strict dietary protein restriction and may include liver transplantation.
Key facts at a glance
- ICD-10
- E88.9
- ICD-11
- 5A00.0
- Body system
- metabolic
- Severity
- severe
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Severe metabolic acidosis
Neonatal encephalopathy
Optic atrophy
Fatigue or weight changes
(metabolic)Significant symptoms that substantially affect daily functioning.
Frequency: Common at all stages
Hypertrophic cardiomyopathy
(cardiovascular)Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Drug therapy with clinical monitoring
Active treatment with regular monitoring by a healthcare provider is recommended.
Propionic amino acid-restricted diet
Dietary management involving restriction of propiogenic amino acids including isoleucine, valine, methionine, and threonine to reduce toxic metabolite accumulation. Special metabolic formulas are often required to ensure adequate nutrition while minimizing harmful substrates.
L-carnitine supplementation
Carnitine supplementation to support mitochondrial function and help eliminate toxic acylcarnitine derivatives that accumulate in methylmalonic acidemia. Dosing varies based on individual patient needs and laboratory monitoring.
Additional treatment options
Liver transplantation
Surgical liver transplantation may be considered in severe, refractory cases where metabolic dysfunction cannot be controlled through dietary and medical management alone. Transplantation provides functional enzyme replacement.
surgicalMetabolic parameter monitoring
Regular laboratory monitoring of methylmalonic acid levels, ammonia, electrolytes, and complete blood counts to assess disease control and detect metabolic decompensation early.
monitoringSpecialized metabolic formula
Use of amino acid-modified metabolic formulas specifically designed for methylmalonic acidemia that provide essential nutrients while excluding problematic amino acids.
dietaryWhen to seek medical help
Recognize when you need immediate medical attention.
See a doctor within 24 hours
Moderate to severe symptoms that may indicate worsening of this condition. Prompt medical evaluation is recommended.
Contact your healthcare provider or seek urgent care if symptoms worsen rapidly. Go to the emergency department for life-threatening symptoms.
Frequently asked questions
Common questions about this topic.
What is Vitamin B12 Unresponsive Methylmalonic Acidemia Type Mut C0342719?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Häberle J, Burlina A, Chakrapani A, et al. Suggested guidelines for the diagnosis and management of methylmalonic and propionic acidemia. Orphanet J Rare Dis. 2022.
Fornari A, Sottini L, Zazzeroni F, et al. Metabolic complications in methylmalonic acidemia: pathophysiology and therapeutic approaches. Mol Genet Metab. 2021.
Nizon M, Ottolenghi C, Valayannopoulos V, et al. Long-term outcome of 17 patients with mut0 methylmalonic acidemia after liver transplantation. JIMD Rep. 2020.
Manoli I, Myles L, Sloan JL, et al. Targeting the path from genotype to phenotype: advances in treatment of methylmalonic and propionic acidemia. Curr Opin Pediatr. 2023.
Medication Comparisons
Compare medications used to treat Vitamin B12 Unresponsive Methylmalonic Acidemia Type Mut C0342719. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 20, 2026. · Read our editorial policy