What is ICD-10 code E76.29?

E76.29 is the ICD-10-CM diagnosis code for Other mucopolysaccharidoses. Other mucopolysaccharidoses include rare inherited metabolic disorders such as Sly syndrome and Maroteaux-Lamy syndrome, where the body cannot properly break down complex sugars. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E76.29 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E76.29 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. E76.29 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. E76.29 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 E76.29?

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 E76.29, V28 maps to Specified Lysosomal Storage Disorders at RAF 9.256 while V24 mapped to Other Significant Endocrine and Metabolic Disorders at RAF 0.194. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting E76.29?

Use this code for MPS types IV (other than Morquio), VI, VII, and IX when specifically documented Clearly document which specific mucopolysaccharidosis type is being coded to ensure accurate classification Because E76.29 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.

2026 ICD-10-CM E76.29: Other mucopolysaccharidoses

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Code lookupE76.29Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E76.29

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

Other mucopolysaccharidoses

Other mucopolysaccharidoses include rare inherited metabolic disorders such as Sly syndrome and Maroteaux-Lamy syndrome, where the body cannot properly break down complex sugars.

Buddy Insight

Other mucopolysaccharidoses captures MPS types that do not have individual ICD-10-CM codes, including MPS VI (Maroteaux-Lamy), MPS VII (Sly syndrome), and MPS IX (Natowicz syndrome).

CMS-HCC V28

Mapped

HCC 49

Specified Lysosomal Storage D...

RAF 9.256

CMS-HCC V24

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.194

ACA/HHS

Mapped

HCC 26

HHS-HCC 26

Varies by metal level

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

RAF 0.036

RXHCC

Mapped

HCC 41

Lysosomal Storage Disorders

RAF 3.081

Code Book Path

Official

E76Disorders of glycosaminoglycan metabolism

E76.2Other mucopolysaccharidoses

E76.29Other mucopolysaccharidoses

Inclusion Terms

Official

beta-Glucuronidase deficiency
Maroteaux-Lamy (mild) (severe) syndrome
Mucopolysaccharidosis, types VI, VII

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E76.29 in this effective period.

Related Child Codes

Official

E76.21Morquio mucopolysaccharidoses

E76.22Sanfilippo mucopolysaccharidoses

Includes

Official

ICD-10-CM does not list Includes notes for E76.29 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E76.29 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E76.29 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E76.29 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E76.29 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific MPS type documented (e.g., Maroteaux-Lamy/MPS VI, Sly syndrome/MPS VII, Natowicz/MPS IX)

Confirmatory enzyme assay or genetic testing identifying the specific enzyme deficiency

Current disease manifestations by organ system

Treatment status: enzyme replacement therapy (galsulfase for MPS VI), supportive interventions

MEAT Support

HCC Buddy guidance

Specific MPS type documented (e.g., Maroteaux-Lamy/MPS VI, Sly syndrome/MPS VII, Natowicz/MPS IX)

Confirmatory enzyme assay or genetic testing identifying the specific enzyme deficiency

Current disease manifestations by organ system

Treatment status: enzyme replacement therapy (galsulfase for MPS VI), supportive interventions

Audit Caution

HCC Buddy guidance

Using E76.29 for MPS types that have their own specific codes (I, II, III, IV)

Defaulting to E76.3 (unspecified) when the provider documents a specific MPS type like Maroteaux-Lamy

Not recognizing eponyms: Maroteaux-Lamy = MPS VI, Sly = MPS VII

Failing to code the specific systemic manifestations (cardiac valve disease, corneal clouding, skeletal changes) as additional diagnoses

Common Mistakes

HCC Buddy guidance

E76.01-E76.03 — MPS I subtypes (Hurler, Hurler-Scheie, Scheie): each has its own specific code

E76.1 — MPS II (Hunter syndrome): has its own specific code

E76.22 — MPS III (Sanfilippo): has its own specific code

E76.210-E76.219 — MPS IV (Morquio): has its own specific codes

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is E76.29 an HCC code?

Yes. E76.29 (Other mucopolysaccharidoses) maps to Specified Lysosomal Storage Disorders under the CMS-HCC V28 risk adjustment model (and Other Significant Endocrine and Metabolic Disorders under V24), with a community non-dual aged RAF of 9.256. It is billable for payment year 2026.

Coder answer: E76.29 is billable and maps to V28 HCC 49, Specified Lysosomal Storage Disorders. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code: E76.29
Description: Other mucopolysaccharidoses
HCC (V28): HCC 49 — Specified Lysosomal Storage Disorders
RAF: 9.256
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 49, Specified Lysosomal Storage Disorders

9.256

V24HCC 23, Other Significant Endocrine and Metabolic Disorders

0.194

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

0.036

RxHCCHCC 41, Lysosomal Storage Disorders

3.081

Each model's RAF is its CMS base weight for that model's standard population, so weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. 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.

Work E76.29 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for E76.29

For E76.29 to 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 E76.29 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E76.29 is the ICD-10-CM diagnosis code for other mucopolysaccharidoses. Other mucopolysaccharidoses include rare inherited metabolic disorders such as Sly syndrome and Maroteaux-Lamy syndrome, where the body cannot properly break down complex sugars. E76.29 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, E76.29 maps to Specified Lysosomal Storage Disorders (HCC 49) with a community, non-dual, aged base RAF weight of 9.256. Under the older CMS-HCC V24 model, E76.29 maps to Other Significant Endocrine and Metabolic Disorders (HCC 23) with a community, non-dual, aged base RAF weight of 0.194. 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.

Use this code for MPS types IV (other than Morquio), VI, VII, and IX when specifically documented. Because E76.29 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 E76.29 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Use this code for MPS types IV (other than Morquio), VI, VII, and IX when specifically documented
•Clearly document which specific mucopolysaccharidosis type is being coded to ensure accurate classification

Clinical Significance

Other mucopolysaccharidoses captures MPS types that do not have individual ICD-10-CM codes, including MPS VI (Maroteaux-Lamy), MPS VII (Sly syndrome), and MPS IX (Natowicz syndrome). These are rare but clinically significant lysosomal storage disorders requiring enzyme replacement therapy and multisystem monitoring.

Documentation Requirements

✓Specific MPS type documented (e.g., Maroteaux-Lamy/MPS VI, Sly syndrome/MPS VII, Natowicz/MPS IX)
✓Confirmatory enzyme assay or genetic testing identifying the specific enzyme deficiency
✓Current disease manifestations by organ system
✓Treatment status: enzyme replacement therapy (galsulfase for MPS VI), supportive interventions
✓Provider statement confirming this is a mucopolysaccharidosis type other than I, II, III, or IV

Commonly Confused Codes

•E76.01-E76.03: MPS I subtypes (Hurler, Hurler-Scheie, Scheie): each has its own specific code
•E76.1: MPS II (Hunter syndrome): has its own specific code
•E76.22: MPS III (Sanfilippo): has its own specific code
•E76.210-E76.219: MPS IV (Morquio): has its own specific codes
•E76.3: Mucopolysaccharidosis, unspecified: use only when the type is truly unknown