This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Pseudohypoparathyroidism type 1C is a genetic disorder that is very similar to hypoparathyroidism (parathyroid hormone levels are too low). However, pseudohypoparathyroidism is caused by no response to parathyroid hormone rather than having too little of the hormone itself. This causes low calcium and high phosphate levels in the blood. This condition is also associated with a group of symptoms referred to as Albright’s hereditary osteodystrophy, which includes short stature, a round face, obesity, and short hand bones. This disorder is different than pseudohypoparathyroidism type 1A because people with type 1C do not have abnormal activity of a particular protein (stimulatory protein G (Gs alpha)). Type 1C is inherited in an autosomal dominant fashion and is caused by a specific spelling mistake (mutation) in the GNAS gene.
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