Desbuquois dysplasia type 2 is an autosomal recessive disorder that is characterized by severe pre- and postnatal growth retardation, a short stature, joint laxity, the dislocation of large joints, and a flat face with prominent eyes (Table 1; Desbuquois et al., 1966), and is caused by mutations in XYLT1 (Bui et al., 2014; Silveira et al., 2016; Al-Jezawi et al., 2017; Guo et al., 2017a). The gene discussed is XYLT1; the disease is Desbuquois dysplasia 2.