2026 ICD-10-CM Diagnosis Code E00.1Congenital iodine-deficiency syndrome, myxedematous type

ICD-10-CM Codes›E00–E89›E00-E07›E00

ICD-10-CM E00.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E00.1 is a billable ICD-10-CM diagnosis code for congenital iodine-deficiency syndrome, myxedematous type. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 643 through 645. Coders also document this condition as congenital iodine deficiency syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Thyroid disorders.

Code Identity

ICD-10-CM Code
E00.1
Billable Status
Yes — Valid for Submission
Code Describes
Congenital iodine-deficiency syndrome, myxedematous type
Short Description
Congenital iodine-deficiency syndrome, myxedematous type
Same as the full description in the CMS dataset.
Parent Code
E00
Congenital iodine-deficiency syndrome

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE00-E07Disorders of thyroid gland
CategoryE00Congenital iodine-deficiency syndrome
This CodeE00.1Congenital iodine-deficiency syndrome, myxedematous type

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Congenital iodine deficiency syndrome
  • Endemic congenital iodine deficiency syndrome of myxedematous type
  • Endemic cretinism
  • Myxedema
  • Myxedematous form of cretinism

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Endemic hypothyroid cretinism
  • Endemic cretinism, myxedematous type

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.

    • Cretin, cretinism(congenital) (endemic) (nongoitrous) (sporadic)
      • type
        • hypothyroid
    • Cretin, cretinism(congenital) (endemic) (nongoitrous) (sporadic)
      • type
        • myxedematous
    • Myxedema(adult) (idiocy) (infantile) (juvenile)
      • congenital
    • Syndrome
      • iodine-deficiency, congenital
        • type
          • myxedematous

Clinical ClassificationClinical

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

CCSR END001
Thyroid disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Congenital Hypothyroidism

    a condition in infancy or early childhood due to an in-utero deficiency of thyroid hormones that can be caused by genetic or environmental factors, such as thyroid dysgenesis or hypothyroidism in infants of mothers treated with thiouracil during pregnancy. endemic cretinism is the result of iodine deficiency. clinical symptoms include severe mental retardation, impaired skeletal development, short stature, and myxedema.

  • Myxedema

    a condition characterized by a dry, waxy type of swelling (edema) with abnormal deposits of mucopolysaccharides in the skin and other tissues. it is caused by a deficiency of thyroid hormones. the skin becomes puffy around the eyes and on the cheeks. the face is dull and expressionless with thickened nose and lips.

  • Scleromyxedema

    a connective tissue disorder characterized by widespread thickening of skin with a cobblestone-like appearance. it is caused by proliferation of fibroblasts and deposition of mucin in the dermis in the absence of thyroid disease. most scleromyxedema cases are associated with a monoclonal gammopathy, immunoglobulin igg-lambda.

  • Graves Disease with Pretibial Myxedema and Thyrotoxic Crisis|Graves' disease with pretibial myxedema AND with thyrotoxic crisis

    graves disease associated with thyrotoxic crisis and cutaneous non-pitting edema and plaque formation.

  • Congenital Iodine Deficiency Syndrome, Myxedematous Type|Congenital iodine-deficiency syndrome, myxedematous type

    congenital iodine deficiency syndrome associated with milder mental retardation, short stature, goiter, and hypothyroidism. it results from iodine deficiency and hypothyroidism in the fetus during late pregnancy or in the neonatal period.

  • Myxedema

    a condition characterized by severe hypothyroidism that is caused by autoimmune thyroid gland disorders, surgical reduction of thyroid tissue, radiation exposure, and viral infections. signs and symptoms include generalized fatigue, lethargy, increased body weight, pale, edematous and thickened skin, low blood pressure, constipation and cold intolerance.

  • Myxedema Coma|Myxedema coma

    a life-threatening condition characterized by altered mental status and defective thermoregulation. it is seen in individuals with severe, decompensated hypothyroidism.

  • Scleromyxedema

    a rare chronic and progressive skin disorder characterized by mucin deposition in the skin, resulting in the thickening and hardening of the skin, predominantly in the face, fingers, and extremities.

  • Systemic Atrophy Primarily Affecting the Central Nervous System in Myxedema|Systemic atrophy primarily affecting the central nervous system in myxedema

    evidence of systemic atrophy primarily affecting the central nervous system in myxedema.

  • Endemic Cretinism

    severely reduced physical and mental growth associated with pyramidal and extrapyramidal signs and symptoms, due to dietary iodine deficiency.

Patient EducationClinical

Thyroid Diseases

Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods.

Read the full article at MedlinePlus

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

Convert E00.1 to ICD-9-CMHistory

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

ICD-9-CM
243 Congenital hypothyroidsm
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 E00.1Overview

Is E00.1 (Congenital iodine-deficiency syndrome) a billable code?

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

What MS-DRG does E00.1 group to?

When congenital iodine-deficiency syndrome, myxedematous type is the principal diagnosis on an inpatient stay, it groups to MS-DRG 643, 644, 645, with relative weights from 0.7683 to 1.6461 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E00.1?

Under the General Equivalence Mappings, congenital iodine-deficiency syndrome, myxedematous type converts to ICD-9-CM 243 (congenital hypothyroidsm). 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.