Vitamin B12 Unresponsive Methylmalonic Acidemia Type Mut0 C0342718
A severe metabolic disorder where the body completely lacks an enzyme to process amino acids. Unlike other forms, this type does not respond to vitamin B12. Aggressive management with diet and possibly organ transplant is needed.
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
Profound metabolic acidosis
Basal ganglia lesions
Fatigue or weight changes
(metabolic)Significant symptoms that substantially affect daily functioning.
Frequency: Common at all stages
Failure to thrive
(gastrointestinal)Renal stone formation
(genitourinary)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
Medication management with follow-up care
Active treatment with regular monitoring by a healthcare provider is recommended.
Protein-restricted diet with amino acid supplementation
Implementation of a carefully controlled diet limiting natural protein intake while supplementing with amino acid mixtures devoid of propiogenic amino acids to manage metabolic abnormalities.
Carnitine replacement therapy
Administration of L-carnitine to support mitochondrial cofactor availability and facilitate excretion of toxic acyl compounds through enhanced carnitine conjugation pathways.
Additional treatment options
Hepatic transplantation evaluation
Comprehensive evaluation for liver transplantation candidacy in patients with severe disease unresponsive to conventional management, as liver provides significant metabolic capacity.
surgicalMetabolic crisis surveillance
Systematic monitoring program including plasma amino acids, organic acids, acylcarnitine profile, and ammonia levels to detect early signs of metabolic decompensation.
monitoringMetabolic emergency action plan
Development of a written emergency protocol for acute metabolic decompensation including sick day rules, dietary modifications during illness, and clear instructions for seeking emergency care.
lifestyleWhen 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 Mut0 C0342718?
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.
Hörster F, Baumgartner MR, Viardot C, et al. Long-term outcome in methylmalonic acidemias is influenced by the underlying defect. J Inherit Metab Dis. 2021;44(3):723-737.
Forny P, Hörster F, Ballhausen D, et al. Methylmalonic acidemia: current perspectives on diagnosis and management. Orphanet J Rare Dis. 2023;18(1):45.
Saudubray JM, Baumgartner MR, García-Cazorla À, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. Springer Nature; 2022: Methylmalonic acidemia: pathophysiology and clinical management.
Chandler RJ, Venditti CP. Gene therapy for methylmalonic acidemia: recent advances and future perspectives. Mol Ther. 2020;28(3):659-669.
Medication Comparisons
Compare medications used to treat Vitamin B12 Unresponsive Methylmalonic Acidemia Type Mut0 C0342718. 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