This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Pseudohypoparathyroidism type 1A (PHP1A) is a type of pseudohypoparathyroidism. Pseudohypoparathyroidism occurs when your body is unable to respond to parathyroid hormone, a hormone that controls the levels of calcium, phosphorous, and vitamin D in the blood. The symptoms are very similar to hypoparathyroidism, a condition that occurs parathyroid hormone levels are too low. PHP1A results in low calcium levels and high phosphate levels in the blood. Symptoms are generally first seen in childhood. Symptoms may include cataracts, dental problems, seizures, numbness, and muscle spasms in the hands and feet. People with PHP1A don’t respond to other hormones produced by the body, such as thyroid-stimulating hormone and gonadotropins. PHP1A 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. Pseudohypoparathyroidism type 1A is caused by a genetic variation (mutation) in the GNAS gene and is inherited in an autosomal dominant pattern. PHP1A is diagnosed based on the symptoms, clinical exam, and other laboratory tests. It may be confirmed by the results of genetic testing. Treatment is focused on managing the symptoms.
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