E72.12 Methylenetetrahydrofolate reductase deficiency

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applies from E72 Other disorders of amino-acid metabolism

Excludes1 (never code together)

• disorders of:
• aromatic amino-acid metabolism (E70.-)
• branched-chain amino-acid metabolism (E71.0-E71.2)
• fatty-acid metabolism (E71.3)
• purine and pyrimidine metabolism (E79.-)
• gout (M1A.-, M10.-)

Applies from E72.1 Disorders of sulfur-bearing amino-acid metabolism

Excludes1 (never code together)

• cystinosis (E72.04)
• cystinuria (E72.01)
• transcobalamin II deficiency (D51.2)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 23 — Other Significant Endocrine and Metabolic Disorders
• RxHCC V08: HCC 43 — Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
• ESRD V24: HCC 23

MS-DRG index

Defines the logic of DRG(s) 642 in MDC 10.

Approximate ICD-9-CM (GEMs)

• 270.4 Disturbances of sulphur-bearing amino-acid metabolism (approximate)

Code annotations containing back-references to E72.12

Back-references to E72

• Type 2 Excludes: G11 Hereditary ataxia ("metabolic disorders (E70-E88)")
• Code First: G63 Polyneuropathy in diseases classified elsewhere ("metabolic diseases (E70-E88)")
• Type 2 Excludes: G71 Primary disorders of muscles ("metabolic disorders (E70-E88)")
• Code First: H42 Glaucoma in diseases classified elsewhere ("specified metabolic disorder (E70-E88)")
• Type 2 Excludes: N25.0 Renal osteodystrophy ("metabolic disorders classifiable to E70-E88")
• Type 2 Excludes: N25.81 Secondary hyperparathyroidism of renal origin ("metabolic disorders classifiable to E70-E88")
• Type 1 Excludes: P59 Neonatal jaundice from other and unspecified causes ("jaundice due to inborn errors of metabolism (E70-E88)")
• Type 1 Excludes: R79 Other abnormal findings of blood chemistry ("specific findings indicating disorder of amino-acid metabolism (E70-E72)")
• Type 1 Excludes: R79.83 Abnormal findings of blood amino-acid level ("disorders of amino-acid metabolism (E70-E72)")

Diagnosis Index entries for E72.12

• Deficiency, deficient › methylenetetrahydrofolate reductase (MTHFR)
• Disorder (of) › metabolism NOS › amino-acid › sulfur-bearing › methylenetetrahydrofolate reductase deficiency

Nearby codes

• E72.04 Cystinosis
• E72.09 Other disorders of amino-acid transport
• E72.1 Disorders of sulfur-bearing amino-acid metabolism
• E72.10 Disorders of sulfur-bearing amino-acid metabolism, unspecified
• E72.11 Homocystinuria
• E72.12 Methylenetetrahydrofolate reductase deficiency (this code)
• E72.19 Other disorders of sulfur-bearing amino-acid metabolism
• E72.2 Disorders of urea cycle metabolism
• E72.20 Disorder of urea cycle metabolism, unspecified
• E72.21 Argininemia
• E72.22 Arginosuccinic aciduria