[Therapy for hypophosphatasia]

Hypophosphatasia is a congenital disorder of bone development due to defect of tissue-nonspecific alkaline phosphatase (ALP), characterized by hypomineralization of skeleton and rachitic change of bone. Most severe form of hypophosphatasia is a perinatal form, which is also called a lethal form. Other forms consist of infantile, childhood, adult and odonto types. Unfortunately, therapy for hypophosphatasia is not intended to cure the disease but to relieve associated disorders. For example, treatment with vitamin B(6) is effective for convulsion and low calcium-containing milk for hypercalcemia. Bone marrow transplantation has been reported to treat patients with hypophosphatasia. However, the method must be developed which improves the survival of donor mesenchymal cells in patients. Recombinant ALP infusion is expected in near future because it is reported to be effective in mouse models.