Summary about Disease
Pseudohypoparathyroidism (PHP) is a group of rare genetic disorders characterized by resistance to parathyroid hormone (PTH). PTH is responsible for regulating calcium and phosphate levels in the blood. In PHP, the body doesn't respond properly to PTH, leading to low calcium (hypocalcemia) and high phosphate (hyperphosphatemia) levels, despite high or normal PTH levels. Several subtypes exist, each with varying genetic causes and clinical presentations, including Albright hereditary osteodystrophy (AHO), which is a distinct set of physical characteristics often associated with certain types of PHP.
Symptoms
Symptoms of PHP can vary but commonly include:
Muscle cramps and spasms (tetany)
Numbness and tingling (paresthesia) in the fingers, toes, and around the mouth
Seizures
Fatigue
Bone pain
Short stature
Rounded face
Shortened fingers and toes (particularly the 4th and 5th metacarpals and metatarsals)
Developmental delays (in some subtypes)
Dental problems
Subcutaneous calcifications (calcium deposits under the skin)
Causes
PHP is primarily caused by genetic mutations affecting the GNAS gene. This gene is located on chromosome 20 and is involved in the production of a protein called GsĪ±, which is a component of the PTH receptor signaling pathway. Different types of mutations can cause different subtypes of PHP. These mutations can be inherited from a parent or occur spontaneously. The specific genetic defect determines the subtype of PHP and the severity of symptoms. Some types involve maternal inheritance (only when inherited from the mother is there an effect).
Medicine Used
Treatment for PHP focuses on managing the symptoms and correcting the calcium and phosphate imbalances. Medications commonly used include:
Calcium supplements: To increase blood calcium levels.
Vitamin D supplements (calcitriol or other activated forms): To enhance calcium absorption from the gut.
Phosphate binders: To reduce phosphate levels in the blood (less common, as dietary phosphate control is often sufficient).
In rare instances, PTH analogs may be used, but this is not a typical treatment.
Is Communicable
No, pseudohypoparathyroidism is not communicable. It is a genetic disorder and cannot be spread from person to person.
Precautions
While PHP isn't contagious, certain precautions are important for individuals with the condition:
Regular monitoring: Regular blood tests to check calcium, phosphate, and PTH levels are crucial.
Medical alert: Consider wearing a medical alert bracelet or carrying information about the condition for emergency situations.
Genetic counseling: Genetic counseling is recommended for families with a history of PHP to assess the risk of inheritance.
Dental care: Good dental hygiene is important due to potential dental abnormalities.
Dietary considerations: A balanced diet is important, and sometimes, dietary phosphate restriction might be recommended.
How long does an outbreak last?
PHP is not an infectious disease and does not involve outbreaks. It is a chronic condition that is present from birth or early childhood and requires lifelong management. The symptoms and severity of the condition can fluctuate over time, but there is no "outbreak" period.
How is it diagnosed?
Diagnosis of PHP typically involves:
Blood tests: Measuring calcium, phosphate, and PTH levels in the blood.
Physical examination: Assessing for characteristic physical features like short stature, rounded face, and shortened fingers/toes.
Medical history: Reviewing the patient's and family's medical history.
X-rays: To assess bone structure and detect skeletal abnormalities.
Genetic testing: To confirm the diagnosis and identify the specific genetic mutation.
Urine Tests: Checking calcium levels excreted in the urine.
Timeline of Symptoms
The timeline of symptoms can vary depending on the specific subtype of PHP and the individual. However, a general timeline might look like this:
Infancy/Early Childhood: Symptoms like muscle cramps, seizures, and developmental delays may become apparent. Physical characteristics (short stature, rounded face) may gradually develop.
Childhood/Adolescence: Short stature becomes more noticeable. Dental problems may emerge. Subcutaneous calcifications can develop.
Adulthood: Symptoms persist throughout adulthood and require ongoing management. Long-term complications (e.g., kidney stones, cataracts) may develop.
Important Considerations
PHP is a complex condition with variable presentation, requiring individualized management.
Early diagnosis and treatment are crucial to minimize long-term complications.
Individuals with PHP may benefit from a multidisciplinary team of healthcare professionals, including endocrinologists, geneticists, nephrologists, and dentists.
Support groups and resources for families affected by PHP can provide valuable information and emotional support.
Genetic counseling is essential for families planning to have children.