CCL21 and nervous system disorder: Some genes of the SCL9A family (SLC9A1) have been associated with neurological disorders, such as epilepsy and bovine genes of the SLC family, such as SLC18A2 and SLC6A4, have been identified as candidates associated with bovine temperament, in Charolais populations, SLC18A2 has been shown to have a significant effect on Pen Score [27].