SH3TC2 (SH3 domain and tetratricopeptide repeats 2) is a 1,288 amino acid protein that contains one SH3 domain and eight TPR repeats. The SH3TC2 gene encodes a protein expressed in Schwann cells of peripheral nerves, and localized to the plasma membrane and to the perinuclear endocytic recycling compartment, suggesting a possible function in myelination and/or in regions of axoglial interactions. The SH3TC2 protein is expressed in adult heart, testis, spinal cord, and brain as well as in fetal brain and liver. Mild mononeuropathy of the median nerve (MNMN) is caused by heterozygous mutation in the SH3TC2 gene. Also, Charcot-Marie-Tooth disease type 4C (CMT4C) is a more severe neuropathy caused by homozygous or compound heterozygous mutation in the SH3TC2 gene. Existing as four alternatively spliced isoforms and containing 18 exons, the SH3TC2 gene is conserved in chimpanzee, dog, cow, mouse, rat, chicken and zebrafish, and maps to human chromosome 5q32.