Pseudohypoparathyroidism

What is pseudohypoparathyroidism (PHP)?

Pseudohypoparathyroidism (PHP) is a genetic condition in which your body doesn’t respond to parathyroid hormone (PTH) even though your parathyroid glands produce enough of it. Parathyroid hormone helps maintain proper calcium, phosphorus and vitamin D levels in your blood. PHP disrupts your body’s ability to use the hormones your parathyroid gland makes (parathyroid hormone resistance).

Pseudohypoparathyroidism is different from hypoparathyroidism. People with hypoparathyroidism don’t produce enough PTH to begin with. If you have pseudohypoparathyroidism, you produce normal amounts of PTH, but your body can’t metabolize (process) it properly. As a result, the calcium levels in your blood drop and the phosphorus levels rise. These imbalances can lead to a wide range of health conditions, including muscle cramps, numbness, seizures and dental issues.

How rare is pseudohypoparathyroidism?

Pseudohypoparathyroidism is very rare. Researchers estimate that fewer than 1 out of 100,000 people have it.

The condition usually develops during infancy or childhood. But adults can get it, too.

What causes pseudohypoparathyroidism?

Mutations (changes) in your GNAS gene cause pseudohypoparathyroidism. Some people inherit pseudohypoparathyroidism from a biological parent. Others develop it spontaneously (for no known reason). There are different types of pseudohypoparathyroidism, including:

• PHP-1. This is the most common type. In addition to parathyroid hormone resistance, a person with PHP-1 has skeletal abnormalities like a round face, short stature, short neck and shortened bones in their hands and feet. Healthcare providers call this set of symptoms Albright hereditary osteodystrophy (AHO). People with PHP-1 inherit the GNAS mutation from one of their biological parents. Subtypes of PHP-1 include PHP-1a, PHP-1b and PHP-1c. These subtypes represent small differences in symptoms and how the condition develops.
• PPHP (pseudopseudohypoparathyroidism). This is a limited form of PHP-1. People with PPHP have physical symptoms of AHO but don’t have parathyroid hormone resistance.
• PHP-2. People with PHP-2 have parathyroid hormone resistance but lack the physical symptoms of AHO. Researchers don’t yet know which genetic abnormality causes PHP-2.

What are the symptoms of pseudohypoparathyroidism?

Pseudohypoparathyroidism symptoms vary from person to person and may include:

• Muscle spasms.
• Muscle cramps.
• Numbness or tingling in your hands or feet.
• Seizures.
• Teeth that erupt (grow in) later than expected.
• Weakened tooth enamel.
• Low blood pressure.
• Brittle hair and nails.
• Anxiety.
• Depression.

People with PHP-1 also have Albright hereditary osteodystrophy (AHO). AHO and pseudohypoparathyroidism features may include:

• Round face.
• Short stature.
• Short neck.
• Shortened bones in your hands and feet.
• Obesity.
• Vision issues like cataracts, blurred vision or light sensitivity.
• Bony bumps under your skin.
• Developmental delays.

What are the complications of pseudohypoparathyroidism?

If you have PHP, you’re more likely to develop other endocrine system conditions. These hormonal issues can result in additional symptoms like low energy and low sex drive.

Some people with PHP are also more likely to develop:

• Parkinsonism (tremors, rigidity and slowness of movement).
• Difficulty with fine motor skills.
• Carpal tunnel syndrome (in people with PHP-1).
• Spinal stenosis.
• Sleep apnea (in children).

How do you diagnose pseudohypoparathyroidism?

A healthcare provider will do a physical examination and review your family history. If they suspect pseudohypoparathyroidism, they’ll likely run tests to confirm a diagnosis. These tests may include:

• Blood tests to measure hormone levels.
• Urine tests (pee tests) to measure calcium and phosphorus levels.
• Genetic testing for the GNAS gene.
• Electrocardiogram (EKG) to check for an abnormal heart rhythm.
• Hand X-rays to check for shortened bones.
• CT (computed tomography) scan to look for differences in your brain.

How do you treat pseudohypoparathyroidism?

Pseudohypoparathyroidism treatment aims to restore and maintain proper levels of calcium and phosphorus in your blood. Managing these levels can help reduce your symptoms.

You can’t cure pseudohypoparathyroidism, but you can manage it with ongoing, lifelong treatment. Treatments may include:

• Calcium and vitamin D supplements.
• Calcitriol capsules (a medication that increases calcium in your body).
• Calcitriol injections.
• Growth or thyroid hormone replacement.
• A high-calcium, low-phosphorus diet.

Can I prevent pseudohypoparathyroidism?

You can’t prevent pseudohypoparathyroidism because it’s a genetic condition. But you can reduce your symptoms with consistent management and treatment.

What can I expect if I have pseudohypoparathyroidism?

If you have pseudohypoparathyroidism, you’ll receive ongoing care with your primary care physician. Because PHP can affect several parts of your body, you may also need to see specialists who can help you manage your specific symptoms. Your healthcare team could include:

• Endocrinologists.
• Orthopedic surgeons.
• Pediatricians.
• Neurologists.
• Physical therapists.
• Occupational therapists.
• Nutritionists.
• Dentists.
• Geneticists.
• Pain management specialists.

You’ll likely need to take supplements for the rest of your life. This helps maintain healthy levels of calcium and phosphorus in your blood. While you can’t cure the underlying genetic cause, you can manage your symptoms with proper treatment.

Outlook for pseudohypoparathyroidism

Developmental and intellectual abilities vary significantly depending on the type and severity of the condition. In most cases, people with PHP have a normal life expectancy compared to people without PHP. Your healthcare provider can tell you what to expect in your situation.

When should I see my healthcare provider?

If you have pseudohypoparathyroidism, see your healthcare provider regularly so they can monitor the levels of calcium and phosphorus in your blood. Routine appointments can help things stay on track.

Call 911 or head to your nearest emergency room if you develop severe symptoms like difficulty breathing, painful muscle cramps or seizures.

A note from Cleveland Clinic

Pseudohypoparathyroidism is a rare condition, so it can be difficult to find others who’re going through the same thing. That can feel isolating at times. If you or your child received a PHP diagnosis, talk to your healthcare provider about support groups and educational resources. These things can help you find ways to improve your symptoms and overall quality of life.