Primary PIPO, including sporadic or familial myopathy, neuropathy, mesenchymopathy, mitochondrial diseases, or neuropathy, has been linked to mutations such as ACTG2, SOX10, POLGI, FLNA, L1CAM, MYH11, MYLK, LMOD1, MYL9, RET, TYMP, RAD21, and SGOL1 (20–22). This evidence concerns the gene L1CAM and mitochondrial disease.