Background Expanded GGGGCC hexanucleotide repeats. ranging from hundreds to thousands in number. located in the noncoding region of the chromosome 9 open reading frame 72 ( C9orf72 ) gene represent the most common genetic abnormality for familial and sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (abbreviated as C9ALS). Currently. https://www.lightemupsequences.com/great-pick-20683-best-mega/