CHST3 and Larsen syndrome: Moreover, missense mutations in the human Carbohydrate sulfotransferase 3 (CHST3) gene, involved in the production of CS, have been shown to be associated with Larsen syndrome, humero-spinal dysostosis [24], and Omani-type spondyloepiphyseal dysplasia [25], all of which cause severe skeletal abnormalities.