Pseudohypoparathyroidism: Difference between revisions
(Created page with "== Overview == Pseudohypoparathyroidism (PHP) is a rare endocrine disorder characterized by resistance to the parathyroid hormone. Patients with PHP have a low serum calcium and high phosphate, but the parathyroid hormone level is appropriately high (due to feedback from the low calcium). == Classification == There are several subtypes of PHP, which are distinguished by their phenotypic characteristics and sometimes by their specific genetic cause...") |
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The clinical manifestations of PHP are primarily related to the hypocalcemia and can include numbness, tingling, muscle cramps, and seizures. In addition, patients with PHP type 1a and 1c can present with a characteristic set of physical features known as Albright's hereditary osteodystrophy (AHO), which includes short stature, obesity, round face, and subcutaneous calcifications. | The clinical manifestations of PHP are primarily related to the hypocalcemia and can include numbness, tingling, muscle cramps, and seizures. In addition, patients with PHP type 1a and 1c can present with a characteristic set of physical features known as Albright's hereditary osteodystrophy (AHO), which includes short stature, obesity, round face, and subcutaneous calcifications. | ||
[[Image:Detail-79075.jpg|thumb|center|A close-up image of a person's hand showing signs of Trousseau's sign, a symptom of hypocalcemia.|class=only_on_mobile]] | |||
[[Image:Detail-79076.jpg|thumb|center|A close-up image of a person's hand showing signs of Trousseau's sign, a symptom of hypocalcemia.|class=only_on_desktop]] | |||
== Causes == | == Causes == | ||
Latest revision as of 23:47, 16 May 2024
Overview
Pseudohypoparathyroidism (PHP) is a rare endocrine disorder characterized by resistance to the parathyroid hormone. Patients with PHP have a low serum calcium and high phosphate, but the parathyroid hormone level is appropriately high (due to feedback from the low calcium).
Classification
There are several subtypes of PHP, which are distinguished by their phenotypic characteristics and sometimes by their specific genetic causes. These include PHP type 1a, PHP type 1b, PHP type 1c, and PHP type 2.
Signs and Symptoms
The clinical manifestations of PHP are primarily related to the hypocalcemia and can include numbness, tingling, muscle cramps, and seizures. In addition, patients with PHP type 1a and 1c can present with a characteristic set of physical features known as Albright's hereditary osteodystrophy (AHO), which includes short stature, obesity, round face, and subcutaneous calcifications.
Causes
PHP is caused by mutations in the GNAS complex locus, a gene that encodes the alpha-subunit of the stimulatory G protein (Gs alpha). This protein is involved in transmitting signals from several hormones, including parathyroid hormone, to cells. The specific type of PHP is determined by the nature of the mutation and its pattern of inheritance.
Diagnosis
The diagnosis of PHP is based on the biochemical findings of hypocalcemia and hyperphosphatemia in the presence of elevated parathyroid hormone levels. Additional laboratory findings can include elevated urinary cAMP and decreased response to PTH infusion. Genetic testing can confirm the diagnosis and determine the specific subtype.
Treatment
The treatment of PHP is aimed at correcting the hypocalcemia and can include oral calcium supplements and active vitamin D analogs. In addition, patients with PHP type 1a and 1c may benefit from growth hormone therapy to improve their short stature.
Prognosis
The prognosis for patients with PHP is generally good, with appropriate management of the hypocalcemia. However, patients with PHP type 1a and 1c can have additional health problems related to their AHO features, such as obesity and insulin resistance.
Epidemiology
PHP is a rare disorder, with an estimated prevalence of 1 in 20,000 to 50,000 people. It affects both males and females equally and can present at any age, although the hypocalcemia is often detected in childhood.