Autosomal dominant cerebellar ataxia, deafness, and narcolepsy
Rare genetic disorder causing ataxia, deafness, narcolepsy, and dementia.
Autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCADN) is a rare progressive genetic disorder that primarily affects the nervous system. It is characterized by sensorineural hearing loss, narcolepsy with cataplexy, and dementia later in life, with symptoms typically beginning in early-mid adulthood.
- field
- Medical genetics, neurology
- known_for
- Causing ataxia, deafness, narcolepsy, and dementia via DNMT1 mutations
- prevalence
- More than 80 cases from families worldwide described in medical literature
- countries_reported
- Sweden, United States, Italy, Brazil, China, New Zealand, Belgium, United Kingdom, Canada, Germany, Taiwan
- typical_age_of_onset
- About 30 years old
- life_expectancy
- 40–50 years
Lore & Background
ADCADN was first described in 1995 by Melberg et al., who reported five members of a four-generation Swedish family. In that family, cerebellar ataxia and sensorineural deafness presented as an autosomal dominant trait; four members had narcolepsy and two had diabetes mellitus. The oldest members exhibited psychiatric symptoms, neurological anomalies, and optic atrophy, demonstrating the progressive nature of the condition.
Reader's Guide
ADCADN is significant as a rare genetic disorder that links DNA methylation dysfunction to neurodegeneration, narcolepsy, and dementia. The condition is caused by mutations in exon 20–21 of the DNMT1 gene, which encodes DNA methyltransferase 1, an enzyme essential for neuron maturation, differentiation, migration, and survival. The mutations distort DNA methylation, affecting gene expression and disrupting neuron maintenance, leading to psychiatric and cognitive symptoms. Diagnosis relies on whole exome sequencing and symptom examination. With more than 80 cases reported across eleven countries, ADCADN highlights the role of epigenetic regulation in neurological disease and underscores the importance of genetic testing for rare hereditary ataxias.
Did You Know?
- ADCADN was first described in 1995 by Melberg et al. in a four-generation Swedish family.
- The condition is caused by mutations in exon 20–21 of the DNMT1 gene on chromosome 19.
- People with ADCADN typically live only to 40–50 years of age.
- Symptoms include ataxia, sensorineural hearing loss, narcolepsy with cataplexy, and later dementia.
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