LIMK1 and Werner syndrome: While haploinsufficiencies of a number of 7q11.23 genes likely interact during development to produce the brain and behavioral characteristics of WS, LIM domain kinase 1 (LIMK1) may play a particularly important role, since it is preferentially expressed in the brain [25] and its protein product is involved, via the phosphorylation of cofilin, in the regulation of actin, a protein that plays a primary role in the subcellular machinery that drives neuronal migration [26, 27].