Apparent Dominant Inheritance of Hypophosphatasia

Abstract

Since the establishment of hypophosphatasia as a syndrome in 1948 by Rathbun,¹ this disease has come to be recognized as a genetically determined inborn error of metabolism with its primary features being: reduced activity of serum and tissue alkaline phosphatase, abnormal mineralization of bone, and phosphoethanolaminuria.² The genetic mechanisms of hypophosphatasia are as yet undetermined, and it is the purpose of this report to describe a family in which documented hypophosphatasia is present in the father and 2 of his sons, suggesting the possibility of dominant inheritance. Pedigree of the Present Study Figure 1 illustrates the family tree in this study so far as it can be accurately determined. The father (II-3) and 2 of his sons (III-8 and III-9) have been investigated extensively, while the mother (II-7) and the remaining sibs (III-6 and III-7) have been subjected to routine studies in an attempt to determine their genotypes.