Linkage analysis studies and homozygosity mapping (LeGuern et al., 1996) identified the CMT4C disease locus on chromosome 5q32, with subsequent discovery of several mutations in the SH3TC2/KIAA1985 gene (Senderek et al., 2003). The gene discussed is SH3TC2; the disease is Charcot-Marie-Tooth disease type 4C.