B4GALT7 and Ehlers-Danlos syndrome: B3GALT6 and B4GALT7 encode beta-1,3-galactosyltransferase 6 and beta-1,4-galactosyltransferase 7, which help catalyze early steps in the GAG–core protein linkage region; variants in either gene cause spondylodysplastic EDS with vascular manifestations [30,31].