RAB39B and frontotemporal dementia: Furthermore, via its interaction with the chromosome 9 open reading frame 72 (C9orf72) gene product (6, 9, 26), implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), additional roles for RAB39B in postsynaptic GluR subunit expression (37) and autophagy (26) have also been established.