What is ICD-10 code E75.00?

E75.00 is the ICD-10-CM diagnosis code for GM2 gangliosidosis, unspecified. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E75.00 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E75.00 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. E75.00 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. E75.00 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 E75.00?

E75.00 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards E75.00 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting E75.00?

If the specific type of GM2 gangliosidosis is documented (Tay-Sachs disease, Sandhoff disease, or GM2 activator deficiency), use the more specific subcategories E75.01, E75.02, or E75.03 instead of the unspecified code This is a genetic disorder; consider coding the family history and any associated neurological manifestations (developmental delay, seizures, blindness) as secondary diagnoses to provide complete clinical documentation

E75.00: GM2 gangliosidosis, unspecified — ICD-10

ICD-10-CM Code View

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Code lookupE75.00Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

E75.00

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

GM2 gangliosidosis, unspecified

GM2 gangliosidosis is a rare inherited metabolic disorder where harmful fatty substances accumulate in nerve cells and the brain, causing progressive neurological damage. This unspecified code is used when the specific type of GM2 gangliosidosis (such as Tay-Sachs or Sandhoff disease) has not been identified.

Buddy Insight

GM2 gangliosidosis, unspecified, indicates a diagnosed GM2 gangliosidosis without specification of the variant (Tay-Sachs, Sandhoff, or AB variant).

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 41

Lysosomal Storage Disorders

RAF 0.0

Code Trumping

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Code Book Path

Official

E75Disorders of sphingolipid metabolism and other lipid storage disorders

E75.0GM2 gangliosidosis

E75.00GM2 gangliosidosis, unspecified

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for E75.00 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for E75.00 in this effective period.

Related Child Codes

Official

E75.01Sandhoff disease

E75.02Tay-Sachs disease

E75.09Other GM2 gangliosidosis

Includes

Official

ICD-10-CM does not list Includes notes for E75.00 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for E75.00 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for E75.00 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for E75.00 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for E75.00 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider diagnosis of GM2 gangliosidosis

Enzyme assay results: hexosaminidase A and B activity levels

Documentation of why specific type has not been determined

Neurological assessment documenting current functional status

MEAT Support

HCC Buddy guidance

Provider diagnosis of GM2 gangliosidosis

Enzyme assay results: hexosaminidase A and B activity levels

Documentation of why specific type has not been determined

Neurological assessment documenting current functional status

Audit Caution

HCC Buddy guidance

Using this code when Tay-Sachs (E75.02) or Sandhoff (E75.01) has been confirmed by enzyme assay

Confusing GM2 gangliosidosis with GM1 gangliosidosis, which is classified under E75.19

Not querying the provider for enzyme assay results that would distinguish the specific variant

Failing to code neurological manifestations (seizures, blindness, developmental regression) separately

Common Mistakes

HCC Buddy guidance

E75.02 — Tay-Sachs disease: specific GM2 gangliosidosis with hexosaminidase A deficiency

E75.01 — Sandhoff disease: specific GM2 gangliosidosis with hexosaminidase A and B deficiency

E75.09 — Other GM2 gangliosidosis: for GM2 activator protein deficiency (AB variant)

E75.10 — Unspecified gangliosidosis: even less specific, covering all gangliosidosis types

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 E75.00 an HCC code?

No. E75.00 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

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 E75.00

For E75.00to 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 E75.00 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

E75.00 is the ICD-10-CM diagnosis code for gm2 gangliosidosis, unspecified. GM2 gangliosidosis is a rare inherited metabolic disorder where harmful fatty substances accumulate in nerve cells and the brain, causing progressive neurological damage. This unspecified code is used when the specific type of GM2 gangliosidosis (such as Tay-Sachs or Sandhoff disease) has not been identified. E75.00 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

E75.00 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Does not map to any HCC in V24, V28, or ESRD models. Maps only to RxHCC 41 (Rheumatoid Arthritis and Specified Autoimmune Disorders). This is a significant coding consideration — despite being a devastating disease, this code carries no RAF weight in the primary CMS-HCC models.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for E75.00 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•If the specific type of GM2 gangliosidosis is documented (Tay-Sachs disease, Sandhoff disease, or GM2 activator deficiency), use the more specific subcategories E75.01, E75.02, or E75.03 instead of the unspecified code
•This is a genetic disorder; consider coding the family history and any associated neurological manifestations (developmental delay, seizures, blindness) as secondary diagnoses to provide complete clinical documentation

Clinical Significance

GM2 gangliosidosis, unspecified, indicates a diagnosed GM2 gangliosidosis without specification of the variant (Tay-Sachs, Sandhoff, or AB variant). These are devastating lysosomal storage disorders causing progressive neurological deterioration due to accumulation of GM2 gangliosides in neurons. Identifying the specific variant is critical for genetic counseling and management planning.

Documentation Requirements

✓Provider diagnosis of GM2 gangliosidosis
✓Enzyme assay results: hexosaminidase A and B activity levels
✓Documentation of why specific type has not been determined
✓Neurological assessment documenting current functional status
✓Family history and genetic counseling status

Commonly Confused Codes

•E75.02: Tay-Sachs disease: specific GM2 gangliosidosis with hexosaminidase A deficiency
•E75.01: Sandhoff disease: specific GM2 gangliosidosis with hexosaminidase A and B deficiency
•E75.09: Other GM2 gangliosidosis: for GM2 activator protein deficiency (AB variant)
•E75.10: Unspecified gangliosidosis: even less specific, covering all gangliosidosis types
•E75.19: Other gangliosidosis: for non-GM2 gangliosidoses