ICD-10 Code E72.12 – Methylenetetrahydrofolate reductase deficiency (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code E72.12 – Methylenetetrahydrofolate reductase deficiency
What it is
E72.12 identifies methylenetetrahydrofolate reductase deficiency, an inherited disorder affecting folate metabolism and homocysteine processing. Use it when documentation names MTHFR deficiency or a related enzyme deficiency.
Clinical signs
Clinical features vary; refer to documentation. Reported findings may include elevated homocysteine, neurologic symptoms, developmental concerns, or thrombosis risk, depending on the specific presentation recorded.
When to use this code
Use this code when the provider documents methylenetetrahydrofolate reductase deficiency, MTHFR deficiency, or a confirmed inherited folate-metabolism disorder. It may also apply when the diagnosis is stated as a cause of abnormal homocysteine findings. Check documentation if the record only mentions an MTHFR gene variant without deficiency.
Do not use for
Do not use this code for isolated MTHFR polymorphism results without a documented deficiency or disease. Do not assign it for nonspecific folate deficiency, hyperhomocysteinemia, or thrombophilia unless the provider clearly links them to MTHFR deficiency.
Coding tip
Code the condition only when the medical record explicitly supports deficiency, not just genetic testing or family history.