Background: Pseudohypoparathyroidism (Ps-HypoPT) is caused by an inactivating mutation in the GNAS1 gene located on chromosome 20q13. It is characterised by target organ resistance to PTH, resulting in hypocalcaemia and hyperphosphataemia. Ps-HypoPT is often subdivided into different types, which can be distinguished by clinical and hormonal findings. Furthermore the parental inheritance is of importance. Studies on this group of patients are very sparse. The aim of the study was to identify all Danish patients with Ps-HypoPT and access their mortality and morbidity.
Methods: Patients with Ps-HypoPT were identified through the Danish National Patient Registry and the prescription database, with subsequent validation of their individual hospital chart. For each identified case three age- and gender matched controls were randomly extracted from the background population.
Results: We identified a total of 60 cases, equal to a prevalence of 1.1/100.000 inhabitants, 42 were women. Only 23% (14 persons) have an identified mutation in the GNAS gene. Compared with controls, cases have a significantly increased risk of cataract (p<0.01), seizures (p>0.01), neuropsychiatric disorders (p<0.01) and infections (p<0.01). However, mortality, risk of renal disorders, cardiovascular and malignant diseases and fractures were compatible to the general background population. A subgroup analysis on the genetically verified cases showed the same tendencies.
Conclusion: Ps-HypoPT is a rare disease associated with a number of complications, that should be considered when taking care of the group of patients.
Disclosure: The authors declared no competing interests.