The Genetic Foundation of Hypophosphatasia
Dr. Cheryl Greenberg, a pediatrician and geneticist, speaks to Dr. Suham Alexander about the clinical history and manifestations of HPP in her unique patient population in Winnipeg, MB. HPP is over-represented in the Mennonite population in Manitoba due to a “founder” mutation.
HPP is categorized by age of onset: perinatal, infant, juvenile, adult (systemic forms) and odonto-hypophosphatasia (dental form). All patients with HPP must have a low level of alkaline phosphatase.
There is a strong genetic basis for the various forms of HPP. There are more than 300 mutations described in the literature. However, one gene is responsible for the disease, ALPL (chr 1p36 encoding TNSALP). The disease can be inherited in an autosomal recessive (severe forms) or autosomal dominant (milder forms) manner.
Signs and Symptoms of HPP in children and adults
- Short statue and bowed legs
- Delayed developmental milestones (eg. delayed walking)
- Chronic muscle or bone pain
- Joint pain and/or swelling
- Neurological manifestations
- Premature loss of primary teeth
- Enlarged pulp chambers