According to NORD (National Organization of Rare Diseases), Hypophosphatasia (HPP) is a rare genetic disorder characterized by the abnormal development of bones and teeth. These abnormalities occur due to defective mineralization, the process by which bones and teeth take up minerals such as calcium and phosphorus. These minerals are required for proper hardness and strength. Defective mineralization results in bones that are soft and prone to fracture and deformity. Defective mineralization of teeth can lead to premature tooth loss. The specific symptoms can vary greatly from one person to another, sometimes even among members of the same family. There are six major clinical forms of HPP that range from an extremely severe form that can cause stillbirth to a form associated with only premature loss of baby (deciduous) teeth, but no bone abnormalities. HPP is caused by mutations in the tissue nonspecific alkaline phosphatase (ALPL) gene. This gene is also known as the TNSALP gene. Such mutations lead to low activity of the tissue nonspecific alkaline phosphatase enzyme. Depending on the specific form, HPP can be inherited in an autosomal recessive or autosomal dominant manner.
To learn more about Hypophosphatasia, visit Softbones.org. They are a wonderful resource for education and research for the HPP community. Our vision is to compliment their organization as well as One Source (the pharmaceutical patient assistance group) and work together for the benefit of all rare diseases and orphan drug communities.