The diagnosis of Charcot-Marie-Tooth neuropathy type 4 requires clinical, pathologic, and genetic confirmation. Mutations causing CMT4 can be detected in the following genes: GDAP1 (CMT4A), MTMR2 (CMT4B1), SBF2 (CMT4B2), SBF1 (CMT4B3), SH3TC2 (CMT4C), NDRG1 (CMT4D), EGR2 (CMT4E), PRX (CMT4F), FGD4 (CMT4H) and FIG4 (CMT4J). However, some additional loci for CMT4 have been mapped, without any identified gene yet: see for instance CTM4G linked to 10q22 and CMT linked to 8q21.3. Additional single reports have been published about cases of axonal neuropathy of late onset in a Costa Rican family linked to 19q13.3 (in which Rautenstrauss et al 2005 preliminarily reported a mutation in MED25), about an autosomal recessive neuropathy with mutations in LMNA, and about autosomal recessive motor and sensory axonal neuropathy with neuromyotonialoss caused by loss-of-function mutations in HINT1 causing (Zimoń et al 2012).
