PCDH15 and Menkes disease: Roman-Naranjo et al. found co-segregation in several novels and rare variants in the MYO7A gene with other genes including CDH23, PCDH15, and ADGRV1 involved in the mechanoelectric transduction (MET) complex and the interciliary links of the hair cells in several MD families, suggesting a digenic inheritance model [31] (Fig. 1).