G70.2
BillableCongenital and developmental myasthenia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G70.2 an HCC code?
Yes. G70.2 maps to Myasthenia Gravis/Myoneural Conditions and Guillain-Barre under the CMS-HCC V28 risk adjustment model (and Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome under V24).
HCC Category Mapping
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 G70.2
For G70.2 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 G70.2 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G70.2 is the ICD-10-CM diagnosis code for congenital and developmental myasthenia. Myasthenia gravis that is present from birth or develops during early childhood due to genetic or developmental factors. G70.2 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, G70.2 maps to Myasthenia Gravis/Myoneural Conditions and Guillain-Barre (HCC 196) with a community, non-dual, aged base RAF weight of 0.402. Under the older CMS-HCC V24 model, G70.2 maps to Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome (HCC 75) with a community, non-dual, aged base RAF weight of 0.425. 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.
This code is used for congenital forms and neonatal myasthenia gravis. Because G70.2 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 G70.2 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Congenital and developmental myasthenia is a group of inherited disorders affecting neuromuscular transmission present from birth or early childhood, distinct from autoimmune myasthenia gravis. These patients require lifelong management and monitoring for respiratory and bulbar complications. Accurate coding distinguishes genetic from autoimmune forms, which is critical for appropriate treatment planning and risk adjustment.
Documentation Requirements
- ✓Age of onset: neonatal or early childhood presentation
- ✓Genetic testing results identifying specific congenital myasthenic syndrome subtype when available
- ✓Family history supporting congenital/genetic origin
- ✓Clinical features: ptosis, feeding difficulties, hypotonia, delayed motor milestones
- ✓Distinction from autoimmune myasthenia gravis: negative acetylcholine receptor antibodies
- ✓Current treatment and management plan
Commonly Confused Codes
- •G70.00/G70.01 — Autoimmune myasthenia gravis typically develops later in life and has positive antibodies; congenital forms are antibody-negative
- •P94.0 — Transient neonatal myasthenia gravis is a temporary condition in newborns of myasthenic mothers, not a congenital myasthenic syndrome
- •G70.80 — Lambert-Eaton syndrome is acquired, not congenital
- •G71.00 — Muscular dystrophy, unspecified involves muscle fiber disease, not neuromuscular junction defects