This has been linked to common genetic disorders such as amyotrophic lateral sclerosis (ALS), where expanded hexanucleotide GGGGCC repeats are found in C9orf72 and ATXN [93,94], frontotemporal dementia (FTD, with hexanucleotide GGGGCC repeats in C9orf72) [94], polyglutamine-associated ataxias [95], spinocerebellar ataxias (SCAs, with an (CAG)n nucleotide expansion in ATXN1/2), Huntington’s disease, and Friedreich’s ataxia (GAA or TTC) [96,97,98,99]. The gene discussed is C9orf72; the disease is juvenile Huntington disease.