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G71.220 ICD-10-CM Code: X-linked myotubular myopathy

G71.220 maps to CMS-HCC V28 197. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Diseases of myoneural junction and muscle (G70-G73)

G71.220

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

X-linked myotubular myopathy

X-linked myotubular myopathy is a rare inherited muscle disease that primarily affects males, causing severe muscle weakness and difficulty with movement and breathing. The condition is caused by a genetic mutation passed down through families and typically appears in infancy or early childhood.

Buddy the Bee presenting code insight

Buddy Insight

X-linked myotubular myopathy is the most severe form of centronuclear myopathy, predominantly affecting males and typically presenting at birth with profound hypotonia and respiratory failure.

CMS-HCC V28

HCC 197

Code-level coefficient reference

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

HCC 117

Code-level coefficient reference

ESRD/PACE

HCC 76

Code-level coefficient reference

RXHCC

N/A

—

Not mapped

Code Book Path

Official
G71.2Congenital myopathies
G71.22Centronuclear myopathy
G71.220X-linked myotubular myopathy

Inclusion Terms

Official
  • Myotubular (centronuclear) myopathy

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G71.220 in this effective period.

Related Child Codes

Official
G71.228Other centronuclear myopathy

Includes

Official

ICD-10-CM does not list Includes notes for G71.220 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G71.220 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G71.220 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G71.220 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G71.220 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Genetic testing confirming MTM1 gene mutation on the X chromosome
Clinical presentation: severe neonatal hypotonia, respiratory failure at birth
Muscle biopsy showing centrally placed nuclei (myotubular fibers) when available
X-linked inheritance pattern: male patient, carrier mother

MEAT Support

HCC Buddy guidance
Genetic testing confirming MTM1 gene mutation on the X chromosome
Clinical presentation: severe neonatal hypotonia, respiratory failure at birth
Muscle biopsy showing centrally placed nuclei (myotubular fibers) when available
X-linked inheritance pattern: male patient, carrier mother

Audit Caution

HCC Buddy guidance
Using the unspecified congenital myopathy code when MTM1 mutation is genetically confirmed
Not distinguishing X-linked form from autosomal centronuclear myopathies, which have different prognoses
Failing to code ventilator dependence and respiratory failure as separate conditions
Not considering this diagnosis in a profoundly hypotonic male neonate with respiratory failure

Common Mistakes

HCC Buddy guidance
G71.228 — Other centronuclear myopathy is for autosomal dominant or recessive forms, not X-linked
G71.20 — Congenital myopathy, unspecified should not be used when X-linked myotubular myopathy is confirmed
G71.21 — Nemaline myopathy has rod-shaped inclusions on biopsy, not central nuclei
P94.2 — Congenital hypotonia is a symptom code and should not replace the specific myopathy diagnosis

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 G71.220 an HCC code?

Yes. G71.220 (X-linked myotubular myopathy) maps to HCC 197, Muscular Dystrophy under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.426. 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: G71.220 is billable and maps to V28 HCC 197, Muscular Dystrophy. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
G71.220
Description
X-linked myotubular myopathy
HCC (V28)
HCC 197 — Muscular Dystrophy
RAF reference coefficient
0.426
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 197, Muscular Dystrophy
0.426
ESRDHCC 76, Muscular Dystrophy
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 G71.220 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for G71.220

For G71.220 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 G71.220 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

G71.220 is the ICD-10-CM diagnosis code for x-linked myotubular myopathy. X-linked myotubular myopathy is a rare inherited muscle disease that primarily affects males, causing severe muscle weakness and difficulty with movement and breathing. The condition is caused by a genetic mutation passed down through families and typically appears in infancy or early childhood. G71.220 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering diseases of myoneural junction and muscle (g70-g73).

Under the CMS-HCC V28 risk adjustment model, G71.220 maps to Muscular Dystrophy (HCC 197) with a source-labeled community, non-dual, aged reference coefficient of 0.426. No V24 mapping is shown for G71.220; use the applicable model and payment year when reviewing the V28 mapping. 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. 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.

This code is specific to X-linked inheritance pattern; do not use if the myotubular myopathy is autosomal recessive or of unknown inheritance type. Because G71.220 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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 G71.220 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •This code is specific to X-linked inheritance pattern; do not use if the myotubular myopathy is autosomal recessive or of unknown inheritance type
  • •Document the family history and genetic testing results in the medical record to support the X-linked classification, as this distinction is critical for accurate coding and genetic counseling

Clinical Significance

X-linked myotubular myopathy is the most severe form of centronuclear myopathy, predominantly affecting males and typically presenting at birth with profound hypotonia and respiratory failure. Most patients require lifelong ventilatory support. This code carries significant risk adjustment importance given the extreme care complexity and resource utilization associated with this condition.

Documentation Requirements

  • ✓Genetic testing confirming MTM1 gene mutation on the X chromosome
  • ✓Clinical presentation: severe neonatal hypotonia, respiratory failure at birth
  • ✓Muscle biopsy showing centrally placed nuclei (myotubular fibers) when available
  • ✓X-linked inheritance pattern: male patient, carrier mother
  • ✓Respiratory support requirements: ventilator type, hours of use
  • ✓Feeding method: oral versus gastrostomy tube
  • ✓Provider's explicit diagnosis specifying X-linked myotubular myopathy

Commonly Confused Codes

  • •G71.228: Other centronuclear myopathy is for autosomal dominant or recessive forms, not X-linked
  • •G71.20: Congenital myopathy, unspecified should not be used when X-linked myotubular myopathy is confirmed
  • •G71.21: Nemaline myopathy has rod-shaped inclusions on biopsy, not central nuclei
  • •P94.2: Congenital hypotonia is a symptom code and should not replace the specific myopathy diagnosis

Child Codes

G71.220X-linked myotubular myopathy
HCC 197
G71.228Other centronuclear myopathy
HCC 197

Code Hierarchy

└G71Primary disorders of muscles└G71.2Congenital myopathies└G71.22Centronuclear myopathy└G71.220X-linked myotubular myopathy
└G71.220X-linked myotubular myopathy

G71.220 code history

Code setChange
FY2021 (effective Oct 1, 2020)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Because G71.220 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment.

G71.220 maps to CMS-HCC V28 category 197, Muscular Dystrophy. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for G71.220. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

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