HDC and Timothy syndrome: Several genes (such as SLITRK1, HDC, NLGN4, CNTNAP2, IMMP2L, SLC6A4 also known as SERT, and NTN4) and chromosomal loci have been implicated to date although, associations between genetic variation and TS are often limited to specific population-based cohorts or may be restricted to extremely rare mutations identified solely in unique multigenerational pedigrees.