G6PD and proximal spinal muscular atrophy: In this sense, the clinical significance of G6PD variation classification is limited and it should be reasonable to revise the WHO classification to one in which genotypes are removed, while phenotypes, such as enzymatic activity and disease severity, are retained, which are commonly used to classify other monogenic disorders, such as spinal muscular atrophy and androgen insensitivity syndrome (Hughes et al., 2012; Kolb and Kissel 2015).