Meta-Biol

• Pathways

Beta-1,3-galactosyltransferase 6 (B3GALT6) normally transfers a second galactose to the tetrasaccharide linker, an initiator sequence required for the biosynthesis of chondroitin sulfate, dermatan sulfate and heparans. Defects in B3GALT6 cause Ehlers-Danlos syndrome progeroid type 2 (EDSP2; MIM:615349), resulting in a broad range of skeletal and connective tissue disorders characterised by loose skin, spinal deformaty, muscle hypotonia, impaired wound healing and joint dislocation (Okajima et al. 1999, Nakajima et al. 2013, Malfait et al. 2013). Defects in B3GALT6 can also cause spondyloepimetaphyseal dysplasia with joint laxity type 1 (SEMDJL1; MIM:271640), characterised by spinal deformaty and lax joints, especially of the hands and respiratory compromise resulting in early death (Nakajima et al. 2013, Malfait et al. 2013). Mutations causing EDSP2 include S309T and R6W and the frameshift mutations R197Afs*81 and D118Afs*160 (Nakajima et al. 2013, Malfait et al. 2013). Mutations causing SEMDJL1 include M1?, R232C, D156N, C300S, S56G, P67L, D207H and G217S (Nakajima et al. 2013, Malfait et al. 2013).