Then, the number of neurological and neuromuscular diseases found with bidirectional transcription rapidly increased to include SCA2 [10], SCA7 [11], SCA31 [12], SCA36 [13,14], Fragile X-associated tremor/ataxia syndrome (FXTAS) [15], C9ORF72 frontotemporal dementia (FTD)/amyotrophic lateral sclerosis (ALS) [16], Huntington’s disease (HD) [17], Huntington’s disease-like 2 (HDL2) [18], DM2 [6] and Friedreich ataxia (FRDA) [19] (Figure 1). This evidence concerns the gene TK2 and fragile X-associated tremor/ataxia syndrome.