First recognized by Rathbun in1948, hypophosphatasia is an inherited metabolic bone disease similar to rickets. It results from low levels of an enzyme known as alkaline phosphatase (ALP). Alkaline phosphatase is normally present in large amounts in bones and in the liver. But when you have hypophosphatasia, abnormalities in the gene that makes ALP lead to production of inactive ALP. Hypophosphatasia occurs in all races, males and females are affected equally, and it affects all age groups.
             Hypophosphatasia is subdivided into five categories, starting at the lethal form perinatal, next is infantile, then childhood, adult, and finally the least severe form odontohypophosphatasia. These categories of hypophosphatasia depend on the severity of the disease. The severity of Hypophosphatasia is remarkably variable from patient to patient. The people most severely affected are the ones that fail to form a skeleton in the womb and are stillborn. The most mildly affected patients may show only low levels of ALP in the blood, but never suffer bone problems.
             The perinatal and infantile forms of hypophosphatasia are inherited as autosomal recessive conditions. The patient receives one defective gene from each parent. The mild cases are childhood and adult. They are also inherited the same way as perinatal and infantile. Some mild adult and odontohypophosphatasia cases seem to be inherited differently. They are inherited in an autosomal dominant pattern, meaning the patient gets only one defective gene transmitted from one of his/her parents instead of receiving two defective genes from their parents. In the mild forms hypophosphatasia can often be detected during pregnancy, by ultrasound and by measuring the ALP activity.
             The perinatal form is considered lethal which means it will kill you. The infantile form is thought to be fatal in approximately fifty percent of patients. Patients with the other three forms can...