WNT1 and osteogenesis imperfecta: Another study has also shown that a missense mutation in exon 3 (c.505G>T) of WNT1 resulted in the substitution of glycine by cysteine at position 169 (p.G169C); besides, the missense mutation in exon 2 (c.110G>T) of WNT1 resulted in the conversion of isoleucine to threonine at position 37 (p.I37T) in patients with OI [6].