2026 ICD-10-CM Diagnosis Code G25.3Myoclonus

AHRQ’s CCSR groups this code into broader clinical categories.

• Epilepsies, Myoclonic

  a clinically diverse group of epilepsy syndromes characterized either by myoclonic seizures or by myoclonus in association with other seizure types. myoclonic epilepsy syndromes are divided into three subtypes based on etiology: familial, cryptogenic, and symptomatic.

• MERRF Syndrome

  a mitochondrial encephalomyopathy characterized clinically by a mixed seizure disorder, myoclonus, progressive ataxia, spasticity, and a mild myopathy. dysarthria, optic atrophy, growth retardation, deafness, and dementia may also occur. this condition tends to present in childhood and to be transmitted via maternal lineage. muscle biopsies reveal ragged-red fibers and respiratory chain enzymatic defects. (from adams et al., principles of neurology, 6th ed, p986)

• Mucolipidoses

  a group of inherited metabolic diseases characterized by the accumulation of excessive amounts of acid mucopolysaccharides, sphingolipids, and/or glycolipids in visceral and mesenchymal cells. abnormal amounts of sphingolipids or glycolipids are present in neural tissue. intellectual disability and skeletal changes, most notably dysostosis multiplex, occur frequently. (from joynt, clinical neurology, 1992, ch56, pp36-7)

• Myoclonic Epilepsies, Progressive

  a heterogeneous group of primarily familial epilepsy disorders characterized by myoclonic seizures, tonic-clonic seizures, ataxia, progressive intellectual deterioration, and neuronal degeneration. these include lafora disease; merrf syndrome; neuronal ceroid-lipofuscinosis; sialidosis (see mucolipidoses), and unverricht-lundborg syndrome.

• Myoclonus

  involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. this condition may be a feature of some central nervous system diseases; (e.g., epilepsy, myoclonic). nocturnal myoclonus is the principal feature of the nocturnal myoclonus syndrome. (from adams et al., principles of neurology, 6th ed, pp102-3).

• Nocturnal Myoclonus Syndrome

  excessive periodic leg movements during sleep that cause micro-arousals and interfere with the maintenance of sleep. this condition induces a state of relative sleep deprivation which manifests as excessive daytime hypersomnolence. the movements are characterized by repetitive contractions of the tibialis anterior muscle, extension of the toe, and intermittent flexion of the hip, knee and ankle. (adams et al., principles of neurology, 6th ed, p387)

• Opsoclonus-Myoclonus Syndrome

  a neurological condition that is characterized by uncontrolled rapid irregular movements of the eye (opsoclonus) and the muscle (myoclonus) causing unsteady, trembling gait. it is also known as dancing eyes-dancing feet syndrome and is often associated with neoplasms, viral infections, or autoimmune disorders involving the nervous system.

• Parasomnias

  movements or behaviors associated with sleep, sleep stages, or partial arousals from sleep that may impair sleep maintenance. parasomnias are generally divided into four groups: arousal disorders, sleep-wake transition disorders, parasomnias of rem sleep, and nonspecific parasomnias. (from thorpy, sleep disorders medicine, 1994, p191)

• Unverricht-Lundborg Syndrome

  an autosomal recessive condition characterized by recurrent myoclonic and generalized seizures, ataxia, slowly progressive intellectual deterioration, dysarthria, and intention tremor. myoclonic seizures are severe and continuous, and tend to be triggered by movement, stress, and sensory stimuli. the age of onset is between 8 and 13 years, and the condition is relatively frequent in the baltic region, especially finland. (from menkes, textbook of child neurology, 5th ed, pp109-110)

• Intellectual Disability

  subnormal intellectual functioning which originates during the developmental period. this has multiple potential etiologies, including genetic defects and perinatal insults. intelligence quotient (iq) scores are commonly used to determine whether an individual has an intellectual disability. iq scores between 70 and 79 are in the borderline range. scores below 67 are in the disabled range. (from joynt, clinical neurology, 1992, ch55, p28)

• EPM2A wt Allele|EPM2|EPM2A Glucan Phosphatase, Laforin wt Allele|EPM2A, Laforin Glucan Phosphatase Gene|Epilepsy, Progressive Myoclonus Type 2, Lafora Disease (Laforin) Gene|LD|LDE|MELF|MELF2

  human epm2a wild-type allele is located in the vicinity of 6q24.3 and is approximately 353 kb in length. this allele, which encodes laforin, plays a role in protein phosphatase activity and glycogen metabolism. loss of function mutations in the gene are associated with myoclonic epilepsy of lafora 1.

• NHLRC1 wt Allele|EPM2B|Epilepsy, Progressive Myoclonus Type 2B Gene|MALIN|MELF2|NHL Repeat Containing 1 Gene|NHL Repeat Containing E3 Ubiquitin Protein Ligase 1 wt Allele|bA204B7.2

  human nhlrc1 wild-type allele is located in the vicinity of 6p22.3 and is approximately 395 kb in length. this allele, which encodes e3 ubiquitin-protein ligase nhlrc1 protein, is involved in the regulation of misfolded protein and polyglucosan clearance. mutations in the gene are associated with myoclonic epilepsy of lafora 2.

• Myoclonus

  a rapid, involuntary jerk of a muscle or group of muscles.

• Opsoclonus Myoclonus Syndrome|Opsoclonus-Myoclonus Syndrome

  a combination of opsoclonus (involuntary conjugate eye movements of large amplitude) and myoclonic jerks. this can be a paraneoplastic syndrome (a result of brain metastasis) or post-infectious (viral encephalitis).

• Progressive Myoclonus Epilepsy

  a rare group of disorders characterized by the development of myoclonic and tonic-clonic epileptic seizures associated with progressive degeneration of the nervous system.

• Dystonia 11, Myoclonic|DYT11|MDS|Myoclonic Dystonia 11|Myoclonus-Dystonia Syndrome

  an autosomal dominant condition caused by mutation(s) in the sgce gene, encoding epsilon-sarcoglycan. it is characterized by myoclonus of the proximal muscles and dystonia.

Movement Disorders

Movement disorders are neurologic conditions that cause problems with movement, such as:

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