hypophosphatasia /hī′pōfos′fətā″zhə/ [Gk, hypo + phosphoros, lightbearing] , congenital absence of alkaline phosphatase, an enzyme essential to the calcification of bone tissue. Complications include vomiting, growth delay, and often death in infancy. Children who survive have numerous skeletal abnormalities and suffer from dwarfism. There is no known treatment.