2026 ICD-10-CM Diagnosis Code E72.12Methylenetetrahydrofolate reductase deficiency

ICD-10-CM Codes›E00–E89›E70-E88›E72

ICD-10-CM E72.12
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E72.12 is a billable ICD-10-CM diagnosis code for methylenetetrahydrofolate reductase deficiency. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as 5,10-Methylenetetrahydrofolate reductase deficiency. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified nutritional and metabolic disorders.

Code Identity

ICD-10-CM Code
E72.12
Billable Status
Yes — Valid for Submission
Code Describes
Methylenetetrahydrofolate reductase deficiency
Short Description
Methylenetetrahydrofolate reductase deficiency
Same as the full description in the CMS dataset.
Parent Code
E72.1
Disorders of sulfur-bearing amino-acid metabolism

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE70-E88Metabolic disorders
CategoryE72Other disorders of amino-acid metabolism
This CodeE72.12Methylenetetrahydrofolate reductase deficiency

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • 5,10-Methylenetetrahydrofolate reductase deficiency
  • Heterozygous methylenetetrahydrofolate reductase mutation
  • Homocystinuria
  • Homozygous methylenetetrahydrofolate reductase mutation
  • Inherited disorder of folate metabolism
  • Methylene THF reductase deficiency AND homocystinuria

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

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

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR END016
Other specified and unspecified nutritional and metabolic disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Homocystinuria

    autosomal recessive inborn error of methionine metabolism usually caused by a deficiency of cystathionine beta-synthase and associated with elevations of homocysteine in plasma and urine. clinical features include a tall slender habitus, scoliosis, arachnodactyly, muscle weakness, genu varus, thin blond hair, malar flush, lens dislocations, an increased incidence of mental retardation, and a tendency to develop fibrosis of arteries, frequently complicated by cerebrovascular accidents and myocardial infarction. (from adams et al., principles of neurology, 6th ed, p979)

  • Combined Methylmalonic Aciduria and Homocystinuria|Combined methylmalonic acidemia and homocystinuria due to defects in adenosylcobalamin and methylcobalamin synthesis

    a genetically heterogeneous disorder of cobalamin (cbl; vitamin b12) metabolism due to loss of function mutations in the enzymes that synthesize the coenzymes adenosylcobalamin (adocbl) and methylcobalamin (mecbl). this is a subtype of methylmalonic acidemia that includes complementation groups cblc, cbld, cblf, cblj, cbll and cblx.

  • Arakawa Syndrome II|Arakawa's Syndrome 2|Arakawa's Syndrome II|Homocystinuria-Megaloblastic Anemia, cblG Complementation Type|Methionine Synthase Deficiency|Methylcobalamin Deficiency, cblG Type|Tetrahydrofolate Methyltransferase Deficiency|Tetrahydrofolate Methyltransferase Deficiency

    a rare autosomal dominant inherited metabolic disorder characterized by deficiency of the enzyme tetrahydrofolate-methyltransferase. it results in the abnormal metabolism of methylcobalamin. signs and symptoms include mental retardation, megaloblastic anemia, hypotonia, epilepsy, and hepatosplenomegaly.

  • Homocystinuria

    an autosomal recessive inherited metabolic disorder caused by mutations in the cbs, mthfr, mtr, and mtrr genes. it is characterized by abnormalities in the methionine metabolism and is associated with deficiency of cystathionine synthase. it results in the accumulation of homocysteine in the serum. it may affect the cardiovascular, musculoskeletal and the central nervous systems.

  • Homocystinuria-Megaloblastic Anemia, cblE Complementation Type|HMAE|Methylcobalamin Deficiency, cblE Type

    an autosomal recessive condition caused by mutation(s) in the mtrr gene, encoding methionine synthase reductase. it is characterized by homocystinuria and megaloblastic anemia.

  • Methylmalonic Aciduria and Homocystinuria Type D Protein, Mitochondrial|C2orf25 Protein|MMADHC|Methylmalonic Aciduria, cblD Type, And Homocystinuria Protein|Uncharacterized Protein C2orf25, Mitochondrial

    methylmalonic aciduria and homocystinuria type d protein, mitochondrial (296 aa, ~33 kda) is encoded by the human mmadhc gene. this protein plays a role in vitamin metabolism.

  • Methylmalonic Aciduria and Homocystinuria, cblC Type

    an autosomal recessive form of combined methylmalonic aciduria and homocystinuria, caused by mutation(s) in the mmachc gene, encoding methylmalonic aciduria and homocystinuria type c protein.

  • Methylmalonic Aciduria and Homocystinuria, cblD Type|MAHCD

    an autosomal recessive form of combined methylmalonic aciduria and homocystinuria, caused by mutation(s) in the mmadhc gene, encoding cobalamin trafficking protein cbld.

  • Methylmalonic Aciduria and Homocystinuria, cblF Type|MAHCF

    an autosomal recessive form of combined methylmalonic aciduria and homocystinuria, caused by mutation(s) in the lmbrd1 gene, encoding lysosomal cobalamin transport escort protein lmbd1.

  • Methylmalonic Aciduria and Homocystinuria, cblJ Type|MAHCJ

    an autosomal recessive form of combined methylmalonic aciduria and homocystinuria, caused by mutation(s) in the abcd4 gene, encoding lysosomal cobalamin transporter abcd4.

  • MMADHC Gene|MMADHC|MMADHC|Methylmalonic Aciduria (Cobalamin Deficiency) cblD Type, with Homocystinuria Gene

    this gene is involved in vitamin metabolism.

  • MMADHC wt Allele|C2orf25|CL25022|Chromosome 2 Open Reading Frame 25 Gene|HSPC161|Methylmalonic Aciduria (Cobalamin Deficiency) cblD Type, with Homocystinuria wt Allele|Methylmalonic Aciduria, cblD Type, and Homocystinuria Gene|My011|cblD

    human mmadhc wild-type allele is located in the vicinity of 2q23.2 and is approximately 18 kb in length. this allele, which encodes methylmalonic aciduria and homocystinuria type d protein, mitochondrial, plays a role in the mediation of vitamin b12 metabolism. mutation of the gene is associated with some cases of homocystinuria, and methylmalonic aciduria.

  • Cyanocobalamin Reductase / Alkylcobalamin Dealkylase|Alkylcobalamin:Glutathione S-Alkyltransferase|CblC|Cyanocobalamin Reductase (Cyanide-Eliminating)|EC 1.16.1.6|EC 2.5.1.15|MMACHC|Methylmalonic Aciduria and Homocystinuria Type C Protein

    cyanocobalamin reductase / alkylcobalamin dealkylase (282 aa, ~32 kda) is encoded by the human mmachc gene. this protein is involved in cobalamin transport and the decyanation of cyanocob(iii)alamin (cyanocobalamin, cncbl) to yield cob(ii)alamin and cyanide and the dealkylation of alkylcob(iii)alamins using a thiolate of glutathione to generate cob(i)alamin and the corresponding glutathione thioether.

  • MMACHC wt Allele|DKFZP564I122|Metabolism of Cobalamin Associated C wt Allele|Methylmalonic Aciduria (Cobalamin Deficiency) cblC Type, with Homocystinuria Gene|cblC

    human mmachc wild-type allele is located in the vicinity of 1p34.1 and is approximately 13 kb in length. this allele, which encodes cyanocobalamin reductase / alkylcobalamin dealkylase protein, plays a role in cobalamin transport and the conversion of cyanocobalamin and alkylcobalamin to cobalamin. mutation of the gene is associated with methylmalonic aciduria and homocystinuria cblc type.

Patient EducationClinical

Amino Acid Metabolism Disorders

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Your digestive system breaks the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert E72.12 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
270.4 Sulph amino-acid met dis
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About E72.12Overview

Is E72.12 (Disorders of sulfur-bearing amino-acid metabolism) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report methylenetetrahydrofolate reductase deficiency on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of E72.12?

Under the General Equivalence Mappings, methylenetetrahydrofolate reductase deficiency converts to ICD-9-CM 270.4 (sulph amino-acid met dis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.