TRPV4 and proximal spinal muscular atrophy: They found two mutations in two families with SP-SMA and CMT2C: one was c.C946T in exon 6 of TRPV4 (p.Arg316Cys) in a family with SP-SMA, and the other was c.G806A in exon 5 of TRPV4 (p.Arg269His) in a family with HMSN IIC/CMT2C.