Yes. E76.22 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. E76.22 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.

Which HCC does E76.22 map to under V28?

E76.22 maps to CMS-HCC V28 HCC 49 (Specified Lysosomal Storage Disorders). The category numbers, labels, and conditions come from the CMS-HCC V28 model file for payment year 2026.

2026 ICD-10-CM E76.22: Sanfilippo

E76.22 maps to CMS-HCC V28 49. A source-labeled RAF reference is available. Confirm the documented diagnosis and applicable coding requirements. MEAT criteria · RAF Calculator · HCC Buddy coding tools

ICD-10-CM Code View

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Code lookupE76.22

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E76.22

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

Sanfilippo mucopolysaccharidoses

Sanfilippo mucopolysaccharidosis is a rare inherited metabolic disorder characterized by severe neurological deterioration, behavioral problems, and progressive dementia in childhood.

Buddy Insight

Sanfilippo mucopolysaccharidosis (MPS III) is characterized by severe progressive neurodegeneration with relatively mild somatic features, making it distinct from other MPS types.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

Mapped

HCC 49

Specified Lysosomal Storage D...

Code-level coefficient reference

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Mapped

HCC 026

HHS-HCC 026 adult, RAF varies...

Code-level coefficient reference

ESRD/PACE

Mapped

HCC 23

Other Significant Endocrine a...

Code-level coefficient reference

RXHCC

Mapped

HCC 41

Lysosomal Storage Disorders

Code-level coefficient reference

Code Book Path

Official

E76Disorders of glycosaminoglycan metabolism E76.2Other mucopolysaccharidoses E76.22Sanfilippo mucopolysaccharidoses

Inclusion Terms

Official

Mucopolysaccharidosis, type III (A) (B) (C) (D)
Sanfilippo A syndrome
Sanfilippo B syndrome
Sanfilippo C syndrome
Sanfilippo D syndrome

Excludes 2

Official

Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88

Related Codes

Official

E76.21Morquio mucopolysaccharidoses E76.29Other mucopolysaccharidoses

Includes

Official

No Includes notes are included in this display for E76.22. Check the code and parent instructions in the Code Book.

Excludes 1

Official

transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E70-E88
androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88
congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88
hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88
Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88
5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88

Code First

Official

No Code First sequencing instructions are included in this display for E76.22. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E76.22. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E76.22. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Specific diagnosis of Sanfilippo syndrome or MPS III documented

Subtype if known (A, B, C, or D) though all map to the same code

Confirmatory enzyme assay or genetic testing results

Neurological and behavioral assessment: hyperactivity, aggression, sleep disturbance, cognitive regression

MEAT Support

HCC Buddy guidance

Specific diagnosis of Sanfilippo syndrome or MPS III documented

Subtype if known (A, B, C, or D) though all map to the same code

Confirmatory enzyme assay or genetic testing results

Neurological and behavioral assessment: hyperactivity, aggression, sleep disturbance, cognitive regression

Audit Caution

HCC Buddy guidance

Misdiagnosing as autism or behavioral disorder when early Sanfilippo presents with behavioral regression and hyperactivity

Coding only the neurological or behavioral manifestations without the underlying MPS III diagnosis

Using E76.3 (unspecified MPS) when Sanfilippo is clearly documented

Failing to recognize that relatively mild somatic features distinguish Sanfilippo from other MPS types with neurodegeneration

Common Mistakes

HCC Buddy guidance

E76.01 — Hurler syndrome (MPS I-H): has similar neurological decline but with prominent somatic features

E76.1 — Hunter syndrome (MPS II): may have neurological involvement but also hepatosplenomegaly and coarse features

F84.0 — Autistic disorder: behavioral symptoms of Sanfilippo may initially mimic autism

G31.89 — Other degenerative diseases of nervous system: Sanfilippo is metabolic, not a primary neurodegenerative disorder

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 E76.22 an HCC code?

Yes. E76.22 (Sanfilippo mucopolysaccharidoses) maps to HCC 49, Specified Lysosomal Storage Disorders under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 9.256. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: E76.22 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: E76.22
Description: Sanfilippo mucopolysaccharidoses
HCC (V28): HCC 49 — Specified Lysosomal Storage Disorders
RAF reference coefficient: 9.256
Billable: Yes
Payment year: 2026

HCC Category Mapping

V28HCC 49, Specified Lysosomal Storage Disorders

9.256

ESRDHCC 23, Other Significant Endocrine and Metabolic Disorders

Not separately weighted

RxHCCHCC 41, Lysosomal Storage Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. 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 context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work E76.22 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E76.22

For E76.22, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

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

Coder workflow notes

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What This Code Means

E76.22 is the ICD-10-CM diagnosis code for sanfilippo mucopolysaccharidoses. Sanfilippo mucopolysaccharidosis is a rare inherited metabolic disorder characterized by severe neurological deterioration, behavioral problems, and progressive dementia in childhood. E76.22 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, E76.22 maps to Specified Lysosomal Storage Disorders (HCC 49) with a source-labeled community, non-dual, aged reference coefficient of 9.256. No V24 mapping is shown for E76.22; use the applicable model and payment year when reviewing the V28 mapping. For CY2026 non-PACE Medicare Advantage, CMS uses 100% of the 2024 CMS-HCC model (V28). PACE uses a separate model blend. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Sanfilippo syndrome has four subtypes (A, B, C, D) based on different enzyme deficiencies; document the specific type if known. For E76.22, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule. 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, source-labeled coefficient references, and MEAT documentation criteria for E76.22 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Sanfilippo syndrome has four subtypes (A, B, C, D) based on different enzyme deficiencies; document the specific type if known
•Document neuropsychiatric symptoms, developmental regression, and behavioral changes as these are hallmark features

Clinical Significance

Sanfilippo mucopolysaccharidosis (MPS III) is characterized by severe progressive neurodegeneration with relatively mild somatic features, making it distinct from other MPS types. The four subtypes (A-D) involve different enzyme deficiencies but share a clinical picture of behavioral disturbances, sleep disorders, cognitive decline, and shortened lifespan, with onset typically in early childhood.

Documentation Requirements

✓Specific diagnosis of Sanfilippo syndrome or MPS III documented
✓Subtype if known (A, B, C, or D) though all map to the same code
✓Confirmatory enzyme assay or genetic testing results
✓Neurological and behavioral assessment: hyperactivity, aggression, sleep disturbance, cognitive regression
✓Current functional status and care needs
✓Treatment plan including behavioral management, seizure control, and supportive care

Commonly Confused Codes

•E76.01: Hurler syndrome (MPS I-H): has similar neurological decline but with prominent somatic features
•E76.1: Hunter syndrome (MPS II): may have neurological involvement but also hepatosplenomegaly and coarse features
•F84.0: Autistic disorder: behavioral symptoms of Sanfilippo may initially mimic autism
•G31.89: Other degenerative diseases of nervous system: Sanfilippo is metabolic, not a primary neurodegenerative disorder
•E76.29: Other mucopolysaccharidoses: for MPS types other than specifically coded ones