COL1A2 and Salla disease: Hundreds of genes are involved in the pathogenesis of SD, but most of them are yet to be elucidated, rendering genotyping almost infeasible except those most common such as fibroblast growth factor receptor 3 (FGFR3), collagen type I alpha 1 chain (COL1A1), collagen type I alpha 2 chain (COL1A2), diastrophic dysplasia sulfate transporter (DTDST), and SRY-box 9 (SOX9).