Alkaline Phosphatase Replacement Therapy.

Hypophosphatasia (HPP) is a rare genetic disease, characterized by the defective production of tissue-non-specific alkaline phosphatase (TNSALP). Six subtypes of the disease - affecting neonates (beginning in utero), infants, children, or adults - are recognized: perinatal lethal, prenatal benign, infantile, childhood, adult, and odontohypophosphatasia. The clinical presentation of these subtypes is very different and the severity ranges from mild to lethal. This chapter, after an overview of the genetics, epidemiology, classification, and clinical presentation of the different forms of HPP, will review the current experience with enzyme replacement therapy (ERT).