The PTH1R gene encodes a parathyroid hormone / parathyroid hormone-related peptide receptor (PTH / PTHRP). Mutations in PTH1R can cause Chondrodysplasia, Blomstrand type (BOCD; MIM 215045), Eiken syndrome (MIM 600002), Failure of tooth eruption, primary (PFE; MIM 125350) and Metaphyseal chondrodysplasia, Jansen type (MIM 156400). 

BOCD is autosomal recessive disorder. It results from loss of function mutations of PTH receptors. BOCD is a lethal chondrodysplasia characterized by short limbs, polyhydramnios, hydrops fetalis, facial anomalies, increased bone density, and advanced skeletal maturation. 

Eiken syndrome is an autosomal recessive disorder caused by truncation mutations in PTH1R. It is characterized by severely retarded ossification of epiphyses, pelvis, hands, and feet as well as abnormal modeling of the bones.

PFE is a non-syndromic autosomal dominant disorder caused by haploinsufficiency of PTH1R. Teeth in the posterior quadrants of the upper and lower jaw are preferentially affected and usually result in an open bite extending from anterior to posterior. Ankylosis of deciduous teeth is also seen.

The Jansen type of metaphyseal chondrodysplasia is an autosomal dominant disorder caused by constitutively active heterozygous mutations in PTH1R. It is characterized by severe growth plate abnormalities that lead to short-limbed dwarfism. Other findings include bowed limbs, joint contractures, clinodactyly, deafness and generalized osteopenia. Affected individuals also have hypercalcemia and hypophosphatemia with normal or low PTH / PTHRP levels.