GM3 synthase deficiency (GM3SD; OMIM 609056), also known as salt and pepper development regression syndrome (SPDRS), is an autosomal recessive disorder caused by homozygous or compound heterozygous mutations in the ST3 Beta-Galactoside Alpha-2,3-Sialyltransferase 5 (ST3GAL5) gene located at 2p11.2 [1]. Here, ST3GAL5 is linked to GM3 synthase deficiency.