Raised serum alkaline phosphatase activity in one family.

Eleven members of the same family were studied after an incidental detection of raised serum alkaline phosphatase activity in one of them without any apparent underlying cause. Three other members were found to have the same abnormality; none of them had an associated disease. In the four cases with elevated serum alkaline phosphatase levels, its activity showed a preponderance of the bone isoenzyme. Studies of the erythrocyte and histocompatibility antigens in nine members of the family, as well as idiograms of karyotypes of four of them, did not show any relation between histocompatibility antigens and the raised levels of serum alkaline phosphatase. Also, no chromosomal abnormality is shown from karyotypes. The data suggest a probable autosomal dominant pattern of inheritance.