Characterisation of Adult-Onset Hypophosphatasia

Hypophosphatasia (HPP) is an inherited condition which causes a defect in bone calcification, leading to weak bones. Early childhood forms are severe and easily recognised, and there is now a drug treatment which is very effective in children. Adult forms are milder, often missed by doctors or confused with osteoporosis. This is important because the usual osteoporosis treatments may be harmful in HPP, and increase the risk of broken bones. One of the reasons it is missed is a lack of research describing the typical features of HPP, so doctors don't recognise the signs, and don't know when or how to test for it. The aim of this study is to establish clear criteria (from clinical history, examination and blood tests) to identify people with HPP. The results will also determine if there should be a trial of drug treatment for adults with HPP.