What Is Hypophosphatasia?

Hypophosphatasia, also known as HPP, is a rare, genetic disorder that can affect people of all ages. It is caused by mutations in the ALPL gene, which encodes the enzyme alkaline phosphatase (ALP). ALP is involved in the mineralization of bones and teeth, so mutations in the ALPL gene can lead to problems with bone formation and mineralization, resulting in weak and brittle bones. Hypophosphatasia can also affect the kidneys, causing problems with filtering waste products from the blood and leading to kidney stones and kidney failure.

There are several types of hypophosphatasia, each with its own unique features and symptoms. The most severe form of hypophosphatasia is infantile hypophosphatasia, which is present at birth and can cause life-threatening complications. Other forms of hypophosphatasia include childhood hypophosphatasia, juvenile hypophosphatasia, and adult hypophosphatasia, which vary in their severity and symptoms.

Symptoms of hypophosphatasia can include:

- Bone pain

- Difficulty walking

- Muscle weakness

- Joint pain

- Fractures

- Tooth decay

- Kidney stones

- Kidney failure

- Hearing loss

- Respiratory problems

- Seizures

- Intellectual disability

Diagnosis of hypophosphatasia is based on:

- Blood tests to measure ALP levels

- Imaging studies to assess bone and joint health

- Genetic testing to identify mutations in the ALPL gene

Treatment for hypophosphatasia may include:

- Enzyme replacement therapy to increase ALP levels

- Medications to improve bone mineralization

- Surgery to correct bone deformities

- Physical therapy to strengthen muscles and bones

Hypophosphatasia is a rare and challenging condition, but with proper diagnosis and treatment, people with HPP can lead full and active lives. Ongoing research is focused on developing new treatments and therapies to improve outcomes for people with HPP.