Therefore, in the present study, we aimed to clarify fine morphological changes in Cx36-made electrical synapses and chemical synapses during the early stages of ALS, by investigating lumbar spinal cord anterior horn cells from SOD1G93A transgenic ALS model mice as well as the morphologically well-preserved motor neurons in the lumbar spinal cord from bulbar or upper limb onset human autopsied ALS cases. Here, GJD2 is linked to amyotrophic lateral sclerosis.