“…Caine et al found no evidence for a linkage between a gene locus determining susceptibility to tic disorder and the HLA loci (Caine et al, 1985). However, in clinical practice, the comorbidity of allergy and tic disorder is usually noted (Chang et al, 2011;Finegold, 1985;Kim, Moote, & Mazza, 1997). Some evidence has supported the cytokines hypothesis regarding tic disorder (Bos-Veneman et al, 2010;Leckman et al, 2005;Martino, Dale, Gilbert, Giovannoni, & Leckman, 2009;Morer et al, 2010).…”