While no pathogenic MMRN1 mutations are reported, G845R and G848R mutations in the GPAGPOGPI motif are associated with type II (perinatal lethal) osteogenesis imperfecta and a G852C mutation in GPAGPOGPQ is associated with type IV (vascular type) Ehlers‐Danlos syndrome, which causes hematomas, hemothorax, and vessel rupture.70, 71. This evidence concerns the gene MMRN1 and osteogenesis imperfecta.