Rare Neurodegenerative Disorders Share DNA Repeat Mutation

Genomics researchers have found that at least four rare neurodegenerative diseases result from CGG (cytosine-guanine-guanine) repeat mutations the DNA located in distant, seemingly unrelated areas of the genome.

Noncoding repeat expansions cause various neuromuscular diseases, including myotonic dystrophies, fragile X tremor/ataxia syndrome, some spinocerebellar ataxias, amyotrophic lateral sclerosis, and benign adult familial myoclonic epilepsies.

Inspired by the striking similarities in the clinical and neuroimaging findings between neuronal intranuclear inclusion disease (NIID) and fragile X tremor/ataxia syndrome caused by noncoding CGG repeat expansions in the FMR1 (fragile X mental retardation 1) gene, investigators at the University of Tokyo (Japan) used advanced next-generation genome sequencing and data analysis techniques to search directly for repeat expansion mutations.

Results of the DNA sequencing study identified noncoding CGG repeat expansions in the NBPF19 (Neuroblastoma breakpoint family member 19) gene as the causative mutations for NIID. More...