Hypophosphatasia (HPP) is a disorder that affects how the body deposits minerals like calcium and phosphorus into teeth and bones, making them strong. There are different forms of HPP, ranging from severe to mild.
In the severe form, babies can be stillborn or born with short limbs, weak skull bones, and breathing problems. Some infants die in their first few weeks due to respiratory failure. Less severe cases might show signs like early loss of baby teeth, shorter height, bowed legs, and difficulty walking. Teeth might also crack or decay easily. There’s a mild form of HPP that only affects teeth, causing abnormal development and early tooth loss, without affecting bones. In the most severe cases, infants might need help to breathe and surgery. Vitamin B6 can help with seizures, and regular dental checkups are crucial to preserve teeth. Pain relievers and orthotics can help manage bone pain and fractures. It’s important to avoid certain medications and excess vitamin D.
HPP is caused by pathogenic (disease-causing) variants in the ALPL gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Ashkenazi Jewish descent have a 1 in 825 chance to be a carrier.
Other names for this condition are deficiency of alkaline phosphatase and phosphoethanolaminuria.
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Revised October 2023
