Interestingly, a Chinese study by Jiang et al. in which a comprehensive single-nucleotide polymorphisms screening was performed in 30 TIO patients with FS and 30 TIO patients without FS found that the polymorphisms of XPR1 and SCL34A3 were associated with FS development in TIO patients [15]. This evidence concerns the gene XPR1 and Feingold syndrome.