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last update : 05-07-2017
Symbol HCAHC
Location 12q23.3
Name cerebral hypomyelination with cerebellar atrophy and hypoplasia of the corpus callosum
Other name(s) hypomyelinating leukodystrophy-8
Corresponding gene POLR3B
Other symbol(s) HLD8
Main clinical features
  • diffuse hypomyelination, atrophy, or hypoplasia of the cerebellum and corpus callosum, but absence of motor deterioration
  • at MRI, high-intensity areas in the white matter in T2-weighted images, cerebellar atrophy, hypoplastic corpus callosum
  • variable features include oligodontia and/or hypogonadotropic hypogonadism (PMID: 33417887))
  • also spasticity, ataxia, and neuropathy, variable global developmental delay/intellectual disability, and dystonia
  • EMG/NCSs for the majority of individuals revealed predominantly demyelinating sensory and motor neuropathy
  • Genetic determination autosomal recessive
    not applicable
    Related entries including CHES (cerebellar hypoplasia with endosteal sclerosis) syndrome (OMIM 213002)
    Function/system disorder neurology
    Type disease
  • de novo heterozygous variants in POLR3B with consistent clinical features that differ from those associated with previously reported bi-allelic mutations (PMID: 33417887))