E88.42 MERRF syndrome

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Myoclonic epilepsy associated with ragged-red fibers

Code also

• progressive myoclonic epilepsy (G40.3-)

Applies from E88 Other and unspecified metabolic disorders

Excludes1 (never code together)

• histiocytosis X (chronic) (C96.6)

Use additional code

• codes for associated conditions

Applies from E88.4 Mitochondrial metabolism disorders

Excludes1 (never code together)

• disorders of pyruvate metabolism (E74.4)
• Kearns-Sayre syndrome (H49.81)
• Leber's disease (H47.22)
• Leigh's encephalopathy (G31.82)
• Mitochondrial myopathy, NEC (G71.3)
• Reye's syndrome (G93.7)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 23 — Other Significant Endocrine and Metabolic Disorders
• RxHCC V08: HCC 43 — Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
• ESRD V24: HCC 23

MS-DRG index

Defines the logic of DRG(s) 642 in MDC 10.

Approximate ICD-9-CM (GEMs)

• 277.87 Disorders of mitochondrial metabolism (approximate)

Code annotations containing back-references to E88.42

Back-references to E88.42

• Code Also: G40.3 Generalized idiopathic epilepsy and epileptic syndromes ("MERRF syndrome, if applicable (E88.42)")

Back-references to E88.4

• Type 1 Excludes: G71.3 Mitochondrial myopathy, not elsewhere classified ("mitochondrial metabolism disorders (E88.4.-)")

Back-references to E88

• Type 2 Excludes: G11 Hereditary ataxia ("metabolic disorders (E70-E88)")
• Code First: G63 Polyneuropathy in diseases classified elsewhere ("metabolic diseases (E70-E88)")
• Type 2 Excludes: G71 Primary disorders of muscles ("metabolic disorders (E70-E88)")
• Code First: H42 Glaucoma in diseases classified elsewhere ("specified metabolic disorder (E70-E88)")
• Type 2 Excludes: N25.0 Renal osteodystrophy ("metabolic disorders classifiable to E70-E88")
• Type 2 Excludes: N25.81 Secondary hyperparathyroidism of renal origin ("metabolic disorders classifiable to E70-E88")
• Type 1 Excludes: P59 Neonatal jaundice from other and unspecified causes ("jaundice due to inborn errors of metabolism (E70-E88)")

Diagnosis Index entries for E88.42

• Disorder (of) › metabolism NOS › mitochondrial › MERRF syndrome (myoclonic epilepsy associated with ragged-red fibers)
• MERRF syndrome (myoclonic epilepsy associated with ragged-red fiber)
• Syndrome › MERRF (myoclonic epilepsy associated with ragged-red fibers)

Nearby codes

• E88.2 Lipomatosis, not elsewhere classified
• E88.3 Tumor lysis syndrome
• E88.4 Mitochondrial metabolism disorders
• E88.40 Mitochondrial metabolism disorder, unspecified
• E88.41 MELAS syndrome
• E88.42 MERRF syndrome (this code)
• E88.43 Disorders of mitochondrial tRNA synthetases
• E88.49 Other mitochondrial metabolism disorders
• E88.8 Other specified metabolic disorders
• E88.81 Metabolic syndrome and other insulin resistance
• E88.810 Metabolic syndrome