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Transcobalamin I Deficiency C0342700

Published: July 22, 2026Updated: August 27, 2026

A rare inherited condition affecting vitamin B12 transport in the blood. It can cause blood abnormalities and neurological symptoms. Treatment involves B12 supplementation and monitoring.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 27, 2026Editorial policy

Key facts at a glance

ICD-10
E88.9
ICD-11
5A00.0
Body system
metabolic
Severity
mild
Chronic
true

Signs and symptoms

Common signs and symptoms that may indicate this condition.

Fatigue

(metabolic)

Fatigue or weight changes

(metabolic)

Mild symptoms that may not significantly impact daily life.

Frequency: Common at all stages

Pallor

(metabolic)

Mild generalized weakness

(metabolic)

Peripheral paresthesia

(metabolic)

Diagnosis and tests

How this condition is diagnosed and what test results mean.

Initial screening tests

1

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

1

Hydroxocobalamin supplementation

Regular intramuscular or subcutaneous injections of hydroxocobalamin (vitamin B12) to bypass absorption issues and maintain adequate cobalamin levels in the body.

medication
2

Lifestyle modification and dietary intervention

Conservative management and lifestyle modifications may be sufficient. Monitor symptoms.

lifestyle
3

Laboratory parameter surveillance

Regular blood tests to monitor cobalamin levels, methylmalonic acid, homocysteine, and hematological parameters to ensure adequate treatment response.

monitoring

Additional treatment options

B12-rich dietary modifications

Incorporation of animal products rich in vitamin B12 such as meat, fish, eggs, and dairy, along with B12-fortified foods as adjunctive nutritional support.

dietary

Folate supplementation support

Adjunctive folate supplementation to support cellular metabolism and hematopoiesis alongside B12 therapy.

complementary

Neurological symptom monitoring

Assessment and support for potential neurological or cognitive symptoms associated with prolonged B12 deficiency, including potential rehabilitation services.

psychological

When to seek medical help

Recognize when you need immediate medical attention.

Schedule an appointment soon

Symptoms associated with this condition. Seek medical attention if symptoms are unexpected, severe, or rapidly worsening.- Contact your healthcare provider if symptoms persist or worsen. Seek emergency care for sudden severe symptoms.

Frequently asked questions

Common questions about this topic.

Q

What is Transcobalamin I Deficiency C0342700?

Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]

general

Sources and references

Authoritative medical sources used to create this content.

1

Hennermann JB, Bühring HG, Mönch S, Ziegler R. Praxisempfehlungen für die Diagnostik und Therapie von Cobalaminstoffwechselstörungen. Monatsschr Kinderheilkd. 2021.

guideline2021
2

Watkins D, Rosenblatt DS. Inherited disorders of folate and cobalamin transport and metabolism. Endocrinol Metab Clin North Am. 2016.

review2016
3

Oussalah A, Gerhardt A, Chery C, et al. Clinical and molecular characterization of transcobalamin I deficiency: a prospective cohort study. Mol Genet Metab. 2022.

clinical_trial2022
4

Froese DS, Fowler B, Baumgartner MR. Vitamin B12, folate, and the methionine regeneration cycle. J Inherit Metab Dis. 2019.

review2019

Medication Comparisons

Compare medications used to treat Transcobalamin I Deficiency C0342700. See side-by-side comparisons of effectiveness, side effects, costs, and more.

View Medication Comparisons

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

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 27, 2026. · Read our editorial policy