Pseudohypoparathyroidism is a condition associated primarily with resistance to the parathyroid hormone. Those with the condition have a low serum calcium and high phosphate, but the parathyroid hormone level (PTH) is appropriately high (due to the low level of calcium in the blood). Its pathogenesis has been linked to dysfunctional G Proteins (in particular, Gs alpha subunit). Pseudohypoparathyroidism is a very rare disorder, with estimated prevalence between 0.3 and 1.1 cases per 100000 population depending on geographic location. Types
Types include:

Type 1a (OMIM  103580)
Has a characteristic phenotypic appearance (Albrights hereditary osteodystrophy), including short fourth and fifth metacarpals and a rounded facies. It is most likely an autosomal dominant disorder. It is also associated with thyroid stimulating hormone resistance. Caused by GNAS1 mutation. Type 1b (OMIM  603233)
Lacks the physical appearance of type 1a, but is biochemically similar. It is associated with a methylation defect in the A/B exon of GNAS1, caused by STX16 disruption. Type 2 (OMIM  203330)
Also lacks the physical appearance of type 1a. Since the genetic defect in type 2 is further down the signalling pathway than in type 1, there is a normal cAMP response to PTH stimulation despite the inherent abnormality in calcium regulation. The specific gene is not identified.While biochemically similar, type 1 and 2 disease may be distinguished by the differing urinary excretion of cyclic AMP in response to exogenous PTH.Some sources also refer to a "type 1c" (OMIM  612462). The phenotype is the same as in type 1a, but red blood cells show normal Gs activity.
See also
Hypoparathyroidism
Pseudopseudohypoparathyroidism
Hyperparathyroidism
Rickets
Hypervitaminosis D

References
Further reading
Mantovani, G; Bastepe, M; Monk, D; de Sanctis, L; Thiele, S; Usardi, A; Ahmed, SF; Bufo, R; Choplin, T; De Filippo, G; Devernois, G; Eggermann, T; Elli, FM; Freson, K; García Ramirez, A; Germain-Lee, EL; Groussin, L; Hamdy, N; Hanna, P; Hiort, O; Jüppner, H; Kamenický, P; Knight, N; Kottler, ML; Le Norcy, E; Lecumberri, B; Levine, MA; Mäkitie, O; Martin, R; Martos-Moreno, GÁ; Minagawa, M; Murray, P; Pereda, A; Pignolo, R; Rejnmark, L; Rodado, R; Rothenbuhler, A; Saraff, V; Shoemaker, AH; Shore, EM; Silve, C; Turan, S; Woods, P; Zillikens, MC; Perez de Nanclares, G; Linglart, A (August 2018). "Diagnosis and management of pseudohypoparathyroidism and related disorders: first international Consensus Statement" (PDF). Nature Reviews. Endocrinology. 14 (8): 476–500. doi:10.1038/s41574-018-0042-0. PMC 6541219. PMID 29959430. == External links ==