In addition, a heterozygous mutation of COL2A1 (c.2014G>T; p.(Gly672Cys)) was found by WES in a multigenerational family with progressive hip disease and mild SMD from the Namaqualand region of northwestern South Africa, which was also confirmed in 23 family members with DDH (Agenbag et al., 2020). The gene discussed is COL2A1; the disease is Hip dysplasia.