As demonstrated by Verheij et al. [43] and Fernández et al. [44], SOX10 variants have been shown to be associated with a more severe phenotype, termed PCWH (peripheral demyelinating neuropathy, central demyelinating leukodystrophy, Waardenburg syndrome, and Hirschsprung’s disease), further supporting the genetic and phenotypic heterogeneity. This evidence concerns the gene SOX10 and Hirschsprung disease.