What is ICD-10 code E76.01?

E76.01 is the ICD-10-CM diagnosis code for Hurler's syndrome. A severe inherited metabolic disorder (mucopolysaccharidosis type I) where the body cannot break down certain complex sugars, causing progressive damage to multiple organs including the heart, bones, and brain. E76.01 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E76.01 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E76.01 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E76.01 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for E76.01?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For E76.01, V28 maps to Lysosomal Storage Disorders at RAF 0.226 while V24 mapped to Other Significant Endocrine and Metabolic Disorders at RAF 0.230. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting E76.01?

Document the age of onset and severity to support medical necessity for specialized treatments Code associated complications such as cardiac valve disease, skeletal abnormalities, or developmental delay separately Because E76.01 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

E76.01 ICD-10 Code: Hurler's syndrome | Lysosomal

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupE76.01Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E76.01

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Hurler's syndrome

A severe inherited metabolic disorder (mucopolysaccharidosis type I) where the body cannot break down certain complex sugars, causing progressive damage to multiple organs including the heart, bones, and brain.

Buddy Insight

CMS-HCC V28

Mapped

HCC 49

Lysosomal Storage Disorders

RAF 0.226

CMS-HCC V24

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.230

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.0

RXHCC

Mapped

HCC 41

Lysosomal Storage Disorders

RAF 0.0

Code Trumping

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Code Book Path

Official

E76Disorders of glycosaminoglycan metabolism

E76.0Mucopolysaccharidosis, type I

E76.01Hurler's syndrome

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E76.01 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E76.01 in this effective period.

Related Child Codes

Official

E76.02Hurler-Scheie syndrome

E76.03Scheie's syndrome

Includes

Official

ICD-10-CM does not list Includes notes for E76.01 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E76.01 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E76.01 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E76.01 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E76.01 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific diagnosis of Hurler syndrome (MPS I-H) as distinct from Hurler-Scheie or Scheie variants

Confirmatory enzyme assay showing alpha-L-iduronidase deficiency or genetic testing with IDUA gene mutation

Current disease manifestations: cardiac (valvular disease), skeletal (dysostosis multiplex), neurological (cognitive decline), corneal clouding

Treatment status: enzyme replacement therapy (laronidase), hematopoietic stem cell transplant history, or supportive care

MEAT Support

HCC Buddy guidance

Specific diagnosis of Hurler syndrome (MPS I-H) as distinct from Hurler-Scheie or Scheie variants

Confirmatory enzyme assay showing alpha-L-iduronidase deficiency or genetic testing with IDUA gene mutation

Current disease manifestations: cardiac (valvular disease), skeletal (dysostosis multiplex), neurological (cognitive decline), corneal clouding

Treatment status: enzyme replacement therapy (laronidase), hematopoietic stem cell transplant history, or supportive care

Audit Caution

HCC Buddy guidance

Confusing Hurler (E76.01), Hurler-Scheie (E76.02), and Scheie (E76.03) — all are MPS I but with very different severity profiles

Coding MPS I generically as E76.3 (unspecified) when the provider has documented Hurler syndrome specifically

Failing to code manifestations separately (cardiac valve disease, skeletal deformities, corneal opacity) as additional diagnoses

Not recognizing that 'gargoylism' is an outdated term for Hurler syndrome and should be coded to E76.01

Common Mistakes

HCC Buddy guidance

E76.02 — Hurler-Scheie syndrome: intermediate MPS I phenotype, less severe than Hurler

E76.03 — Scheie's syndrome: mildest MPS I form with normal intelligence and longer survival

E76.1 — Mucopolysaccharidosis type II (Hunter syndrome): different enzyme deficiency (iduronate-2-sulfatase), X-linked

E76.3 — Mucopolysaccharidosis, unspecified: use only when the specific MPS type is not documented

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is E76.01 an HCC code?

Yes. E76.01 maps to Lysosomal Storage Disorders under the CMS-HCC V28 risk adjustment model (and Other Significant Endocrine and Metabolic Disorders under V24).

HCC Category Mapping

V28HCC 49, Lysosomal Storage Disorders

0.226

V24HCC 23, Other Significant Endocrine and Metabolic Disorders

0.230

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

0.000

RxHCCHCC 41, Lysosomal Storage Disorders

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for E76.01

For E76.01to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed E76.01 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

E76.01 is the ICD-10-CM diagnosis code for hurler's syndrome. A severe inherited metabolic disorder (mucopolysaccharidosis type I) where the body cannot break down certain complex sugars, causing progressive damage to multiple organs including the heart, bones, and brain. E76.01 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

Under the CMS-HCC V28 risk adjustment model, E76.01 maps to Lysosomal Storage Disorders (HCC 49) with a community, non-dual, aged base RAF weight of 0.226. Under the older CMS-HCC V24 model, E76.01 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.230. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Document the age of onset and severity to support medical necessity for specialized treatments. Because E76.01 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E76.01 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document the age of onset and severity to support medical necessity for specialized treatments
•Code associated complications such as cardiac valve disease, skeletal abnormalities, or developmental delay separately

Clinical Significance

Hurler syndrome (mucopolysaccharidosis type I-H) is a severe, progressive lysosomal storage disorder caused by deficiency of alpha-L-iduronidase, leading to accumulation of dermatan sulfate and heparan sulfate. It is the most severe form of MPS I, with life-threatening cardiac, skeletal, and neurological complications typically requiring hematopoietic stem cell transplant or enzyme replacement therapy.

Documentation Requirements

✓Specific diagnosis of Hurler syndrome (MPS I-H) as distinct from Hurler-Scheie or Scheie variants
✓Confirmatory enzyme assay showing alpha-L-iduronidase deficiency or genetic testing with IDUA gene mutation
✓Current disease manifestations: cardiac (valvular disease), skeletal (dysostosis multiplex), neurological (cognitive decline), corneal clouding
✓Treatment status: enzyme replacement therapy (laronidase), hematopoietic stem cell transplant history, or supportive care
✓Functional status assessment and disease progression documentation

Commonly Confused Codes

•E76.02 — Hurler-Scheie syndrome: intermediate MPS I phenotype, less severe than Hurler
•E76.03 — Scheie's syndrome: mildest MPS I form with normal intelligence and longer survival
•E76.1 — Mucopolysaccharidosis type II (Hunter syndrome): different enzyme deficiency (iduronate-2-sulfatase), X-linked
•E76.3 — Mucopolysaccharidosis, unspecified: use only when the specific MPS type is not documented
•E76.29 — Other mucopolysaccharidoses: for MPS types not individually coded (e.g., MPS VI Maroteaux-Lamy, MPS VII Sly)