Contrary to PMM2-CDG, skeletal dysplasia was well characterized in other CDGs, including ALG12-CDG, ALG3-CDG, ALG9-CDG, ALG6-CDG, PGM3-CDG, CSGALNACT1-CDG, SLC35D1-CDG and TMEM165-CDG (Table 1). Here, ALG9 is linked to skeletal dysplasia.