SALL1 and Townes-Brocks syndrome: With respect to the most common mutation reported in humans, Kiefer et al. (2008) proved that a truncated SALL1 protein is produced in B-cells from a TBS patient with p.Arg276Ter, showing that this variant escapes nonsense-mediated decay (NMD) and supporting the hypothesis that expression of a truncated protein is critical in the pathogenesis of TBS [14].