PTH and metaphyseal chondrodysplasia: Considering this it is tempting to speculate whether there are molecular connections between RMRP RNA and PTH/PTHrP in skeletal dysplasias like cartilage-hair hypoplasia, metaphyseal chondrodysplasia Jansen type (OMIM #156400)58 and Blomstrand type chondrodysplasia59, (OMIM #215045).