Chapter VI
Diseases of the nervous system
(G00-G99)

Systemic atrophies primarily affecting the central nervous system
(G10-G13)

G10 Huntington's disease
Huntington's chorea

G11 Hereditary ataxia
Excludes: cerebral palsy ( G80.- )
hereditary and idiopathic neuropathy ( G60.- )
metabolic disorders ( E70-E90 )
G11.0 Congenital nonprogressive ataxia
G11.1 Early-onset cerebellar ataxia
Note: Onset usually before the age of 20
Early-onset cerebellar ataxia with:
· essential tremor
· myoclonus [Hunt's ataxia]
· retained tendon reflexes
Friedreich's ataxia (autosomal recessive)
X-linked recessive spinocerebellar ataxia
G11.2 Late-onset cerebellar ataxia
Note: Onset usually after the age of 20
G11.3 Cerebellar ataxia with defective DNA repair
Ataxia telangiectasia [Louis-Bar]
Excludes: Cockayne's syndrome ( Q87.1 )
xeroderma pigmentosum ( Q82.1 )
G11.4 Hereditary spastic paraplegia
G11.8 Other hereditary ataxias
G11.9 Hereditary ataxia, unspecified
Hereditary cerebellar:
· ataxia NOS
· degeneration
· disease
· syndrome

G12 Spinal muscular atrophy and related syndromes
G12.0 Infantile spinal muscular atrophy, type I [Werdnig-Hoffman]
G12.1 Other inherited spinal muscular atrophy
Progressive bulbar palsy of childhood [Fazio-Londe]
Spinal muscular atrophy:
· adult form
· childhood form, type II
· distal
· juvenile form, type III [Kugelberg-Welander]
· scapuloperoneal form
G12.2 Motor neuron disease
Familial motor neuron disease
Lateral sclerosis:
· amyotrophic
· primary
Progressive:
· bulbar palsy
· spinal muscular atrophy
G12.8 Other spinal muscular atrophies and related syndromes
G12.9 Spinal muscular atrophy, unspecified

G13* Systemic atrophies primarily affecting central nervous system in diseases classified elsewhere
G13.0* Paraneoplastic neuromyopathy and neuropathy
Carcinomatous neuromyopathy ( C00-C97+ )
Sensorial paraneoplastic neuropathy [Denny Brown] ( C00-D48+ )
G13.1* Other systemic atrophy primarily affecting central nervous system in neoplastic disease
Paraneoplastic limbic encephalopathy ( C00-D48+ )
G13.2* Systemic atrophy primarily affecting central nervous system in myxoedema ( E00.1+ , E03.-+ )
G13.8* Systemic atrophy primarily affecting central nervous system in other diseases classified elsewhere