According to The US National Library of Medicine, Mutations in the FGFR3 gene cause achondroplasia (“1. Achondroplasia.”). The FGFR3 gene provides instructions for making proteins that are involved in the development and maintenance of bone and brain tissue (“1. Achondroplasia.”). Two specific mutations in the FGFR3 are responsible for almost all the cases of achondroplasia (“1. Achondroplasia.”). Researchers believe that these mutations cause the FGFR3 protein to be overly active, which interferes with skeletal development and leads to the disturbance in bone growth seen with this disorder (“1. Achondroplasia.”).