CDKL5 and Ataxia: Among the DEE-related mutated genes listed in the OMIM database, ataxia is mainly observed in mutations affecting the following two major categories of protein function: ion channels (e.g., CACNA1A, GABRB1, GABRB2, GABRB3, GABRG2, KCNA2, KCNC2, KCNQ2, SCN1A, SCN1B, SCN2A, SCN8A) and enzymes/regulatory proteins (e.g., ALG13, ARHGEF9, ARV1, CDKL5, FBX028, PIGS) [8, 10, 11, 74].