DNMT1 and hereditary sensory neuropathy-deafness-dementia syndrome: Interestingly, a second condition, hereditary sensory neuropathy with dementia and hearing loss (HSAN1E), is also caused by mutations in DNMT1. While once classified as distinct disorders, we now recognize that HSAN1E and ADCA-DN patients demonstrate significant overlap in clinical features, suggesting that these are likely the same condition with clinical variability depending on location and type of mutation and an individual’s genetic background [10].