The DTWD2 gene at 5q23.1 was identified through SNP rs17144687 in the meta-analysis. This locus also reached genome-wide significant associations (p < 5×10−7) with several flanking SNPs meeting the borderline significant associations in the replication study (rs6868097 with p = 0.0209 and rs6874109 with p = 0.0695). This gene may be functional because rs6868097 has significant cis-acting regulatory effect on DTWD2 transcript expression. Unfortunately, there is little other known biological function of DTWD2 that has been reported up to now. A rare copy number variation was identified in DTWD2 in age-related disorders of blindness, with a focus on primary open-angle glaucoma (Davis et al., 2011). Interestingly, one study showed a sudden blindness in a patient with alcohol abuse (Oksanen, 2002). It possibly implies that DTWD2 may play a role in disorders of blindness and alcohol consumption. Recently, several polymorphisms in DTWD2 were reported to have moderate associations with celiac disease with p-values between 0.000275 and 0.004 (Trynka et al., 2009).
