CSGALNACT1 and skeletal dysplasia: Biallelic loss-of-function mutations in CSGALNACT1 gene results in reduced CSGalNAcT-1 activity leading to altered levels of chondroitin, dermatan, and heparan sulphate and cause a mild skeletal dysplasia with joint laxity and advanced bone age, CSGALNACT1-CDG [42].