2026 ICD-10-CM Diagnosis Code E20.1Pseudohypoparathyroidism

ICD-10-CM Codes›E00–E89›E20-E35›E20

ICD-10-CM E20.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E20.1 is a billable ICD-10-CM diagnosis code for pseudohypoparathyroidism. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 640 through 641. Coders also document this condition as cataract due to pseudohypoparathyroidism. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified endocrine disorders.

Code Identity

ICD-10-CM Code
E20.1
Billable Status
Yes — Valid for Submission
Code Describes
Pseudohypoparathyroidism
Short Description
Pseudohypoparathyroidism
Same as the full description in the CMS dataset.
Parent Code
E20
Hypoparathyroidism

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE20-E35Disorders of other endocrine glands
CategoryE20Hypoparathyroidism
This CodeE20.1Pseudohypoparathyroidism

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cataract due to pseudohypoparathyroidism
  • Genetic syndromic childhood obesity
  • Pseudohypoparathyroidism
  • Pseudohypoparathyroidism and pseudopseudohypoparathyroidism
  • Pseudohypoparathyroidism type 1C
  • Pseudohypoparathyroidism type I A
  • Pseudohypoparathyroidism type I B
  • Pseudohypoparathyroidism type II
  • Pseudopseudohypoparathyroidism

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.

    • Pseudohypoparathyroidism
    • Pseudopseudohypoparathyroidism

Clinical ClassificationClinical

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

CCSR END015
Other specified and unspecified endocrine disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Pseudohypoparathyroidism

    a hereditary syndrome clinically similar to hypoparathyroidism. it is characterized by hypocalcemia; hyperphosphatemia; and associated skeletal development impairment and caused by failure of response to parathyroid hormone rather than deficiencies. a severe form with resistance to multiple hormones is referred to as type 1a and is associated with maternal mutant allele of the alpha chain of stimulatory g protein.

  • Pseudopseudohypoparathyroidism

    a form of pseudohypoparathyroidism characterized by the same features except for the abnormal response to hormones such as parathyroid hormone. it is associated with paternally inherited mutant alleles of the alpha chain of stimulatory g protein.

  • Albright Hereditary Osteodystrophy with Multiple Hormone Resistance|PHP1a|Pseudohypoparathyroidism Type 1a

    parathyroid hormone (pth) resistance caused by heterozygous inactivating mutation(s) of the maternal allele of the gnas gene encoding gs-alpha, resulting in expression of pth from only the paternal allele. clinical manifestations include albright hereditary osteodystrophy, early-onset obesity, and, in some cases, resistance to thyroid-stimulating hormone, gonadotropins, and growth hormone-releasing hormone, reflecting additional manifestations of gs-alpha deficiency.

  • Albright Hereditary Osteodystrophy without Multiple Hormone Resistance|Albright Hereditary Osteodystrophy with Multiple Hormone Resistance|PPHP|Pseudopseudohypoparathyroidism

    a condition caused by inactivating mutation(s) in the paternal allele of the gnas gene, encoding gs-alpha, resulting in expression of the gs-alpha protein from only the maternal allele. affected individuals have the clinical phenotype of albright hereditary osteodystrophy without hormone resistance.

  • Albright's Hereditary Osteodystrophy|Albright Hereditary Osteodystrophy|Albright's Hereditary Osteodystrophy with Multiple Hormone Resistance|PHP1A|Pseudohypoparathyroidism, Type IA

    a rare, autosomal dominant syndrome caused by mutations in the gnas gene. it is characterized by the presence of short stature, obesity, round face, brachydactyly, subcutaneous ossifications, and pseudohypoparathtyroidism.

  • Parathyroid Hormone Resistance|Pseudohypoparathyroidism|Pseudoparathyroidism

    a finding indicating decreased tissue sensitivity to parathyroid hormone.

  • Pseudohypoparathyroidism

    a condition characterized by the insensitivity of the tissues to respond to the activity of the parathyroid hormone. it results in increased levels of parathyroid hormone in the serum, hypocalcemia, and hyperphosphatemia.

  • Renal Parathyroid Hormone Resistance|Pseudohypoparathyroidism Type 1b

    parathyroid hormone resistance caused by defects in methylation in the gnas gene that cause loss of expression of gs-alpha from the maternal allele in renal tissue, resulting in decreased phosphate excretion and increased calcium excretion. individuals with this condition may also have brachydactyly and partial resistance to thyroid-stimulating hormone.

  • Secondary Parathyroid Hormone Resistance|Acquired Parathyroid Hormone Resistance|Acquired Parathyroid Hormone Resistance|Pseudohypoparathyroidism, Type 2|Pseudohypoparathyroidism, Type 2

    parathyroid hormone (pth) resistance caused by vitamin d deficiency and characterized by clinically increased pth concentrations with relative hyperphosphatemia. the diagnosis can be confirmed by finding of a normal cyclic adenosine monophosphate (camp) response to pth infusion, but deficient phosphaturic response, indicating a defect distal to camp generation in renal cells.

Patient EducationClinical

Metabolic Disorders

Metabolism is the process your body uses to get or make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system break the food parts down into sugars and acids, your body's fuel.

Read the full article at MedlinePlus

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

Convert E20.1 to ICD-9-CMHistory

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

ICD-9-CM
275.49 Dis calcium metablsm NEC
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 E20.1Overview

Is E20.1 (Hypoparathyroidism) a billable code?

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

What MS-DRG does E20.1 group to?

When pseudohypoparathyroidism is the principal diagnosis on an inpatient stay, it groups to MS-DRG 640, 641, with relative weights from 0.7782 to 1.3356 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of E20.1?

Under the General Equivalence Mappings, pseudohypoparathyroidism converts to ICD-9-CM 275.49 (dis calcium metablsm NEC). 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.