TOPBP1 and Huntington disease: Indeed, beyond ribosomal biogenesis and RNA metabolism, SNORD13 appears to be involved in a wide range of genomic activities associated with HD pathophysiology (Figure 4, Supplementary Table S1): chromatin remodeling via histone acetylation and methylation (SIRT6, EP300, TAF1, CHD1, KDM5A-B etc.), telomere length maintenance (DKC1,HRNPU, VPRBP) [5], DNA repair and damage response (ERCC6, BAZ1B, FANCD2, TOPBP1) [6,20]; direct modulation of homeobox (HOXA1-7, DLX1-2, OTX2 and others), and zinc-finger proteins (SNAI2, SP1-2, ZMIZ2 and others) [27].