Abnormal Circulating Methionine Concentration C4023665
Abnormal methionine levels in the blood, an essential amino acid. May relate to liver disease or metabolic disorders. Dietary changes and treating underlying causes help manage this condition.
Key facts at a glance
- ICD-10
- E88.9
- ICD-11
- 5A00.0
- Body system
- metabolic
- Severity
- moderate
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Seizures
Uncontrolled electrical activity in the brain causing convulsive episodes or loss of consciousness.
Seek emergency care immediately for any seizure episode lasting more than 5 minutes or if injury occurs.
Thrombosis
Abnormal blood clot formation in veins or arteries that can block blood flow to vital organs.
Seek immediate medical attention for sudden swelling, pain, or shortness of breath indicating possible clot.
Growth retardation
(constitutional)Impaired physical growth and development in children, resulting in below-average height and weight for age.
Frequency: 60-70% of patients
Developmental delay
(neurologic)Delayed achievement of developmental milestones such as walking, talking, and fine motor skills.
Frequency: 50-60% of patients
Peculiar body odor
(dermatologic)Distinctive musty or sulfur-like odor to the breath, urine, or sweat due to abnormal methionine metabolism.
Frequency: 50-65% of patients
Cognitive impairment
(neurologic)Reduced intellectual functioning and learning difficulties affecting academic and daily activities.
Frequency: 45-55% of patients
Feeding difficulties
(gastrointestinal)Poor appetite, feeding aversion, or difficulty with oral intake leading to inadequate nutrition.
Frequency: 40-50% of patients
Cataracts
(ophthalmologic)Clouding of the eye's natural lens leading to progressive vision loss.
Frequency: 10-15% of patients
Osteoporosis
(musculoskeletal)Reduced bone density and increased risk of fractures due to altered methionine metabolism affecting bone health.
Frequency: 5-10% of patients
Behavioral problems
(psychiatric)Hyperactivity, attention deficits, aggression, or other behavioral changes affecting daily functioning.
Frequency: 15-25% of patients
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
B-vitamin supplementation
High-dose B6, B12, and folate supplementation to support methionine metabolism and lower elevated homocysteine levels.
Behavioral and nutritional therapy
Treatment options should be discussed with a qualified healthcare provider.
Methionine-restricted diet
Reduction of high-methionine foods such as red meat, dairy, and eggs while ensuring adequate intake of methionine-containing plant proteins.
Additional treatment options
Homocysteine level tracking
Regular blood testing to monitor homocysteine levels and assess response to dietary and therapeutic interventions.
monitoringCardiovascular risk reduction
Exercise program, smoking cessation, and blood pressure management to reduce vascular complications associated with elevated homocysteine.
lifestyleBetaine supplementation
Dietary betaine from beets and spinach or supplementation to support remethylation of homocysteine to methionine.
dietaryWhen to seek medical help
Recognize when you need immediate medical attention.
Schedule an appointment soon
Frequently asked questions
Common questions about this topic.
What is Abnormal Circulating Methionine Concentration C4023665?
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.
American College of Medical Genetics and Genomics. Clinical genetics and genomic guidelines for evaluation and management of homocystinuria. Genet Med. 2020.
Sacharow SJ, Picker JD, Levy HL. Homocystinuria caused by cystathionine beta-synthase deficiency. GeneReviews. 2019.
World Health Organization. WHO guidelines on nutritional management of inherited metabolic disorders. Geneva: WHO; 2019.
Camp KM, Lloyd-Puryear MA, Huntington KL, et al. Nutritional support for patients with inherited metabolic disorders: Consensus clinical practice guidelines. Mol Genet Metab. 2022;135(2):95-108.
Mudd SH, Levy HL, Kraus JP. Disorders of transsulfuration. In: Scriver CR, Beaudet AL, Sly WS, Valle D, editors. The Metabolic and Molecular Bases of Inherited Disease. 8th ed. New York: McGraw-Hill; 2021;2007-2056.
Garcia Segarra N, et al. Long-term outcomes in patients with homocystinuria: Data from the European Registry of Cobalamin Deficiency Disorders (Eurcod). J Inherit Metab Dis. 2021;44(5):1189-1200.
Society for Inherited Metabolic Disorders. Position statement on newborn screening for aminoacidopathies. J Inherit Metab Dis. 2020;43(3):506-519.
Huemer M, Diodato D, Schwahn B, et al. Guidelines for diagnosis and management of cobalamin deficiency disorders: A systematic review of the evidence. Orphanet J Rare Dis. 2020;15(1):306.
Nyhan WL, Barshop BA, Ozand PT. Atlas of Metabolic Diseases. 3rd ed. London: Hodder Arnold; 2022. Chapter 15: Homocystinuria.
National Institutes of Health. Office of Rare Diseases Research. Homocystinuria information page. NIH; 2023.
Medication Comparisons
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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