The ank gene story

The underlying molecular defect resulting in the abnormal calcification obs erved in ank/ank mice has been identified. The responsible nonsense mutatio n affects the protein product of ank, resulting in diminished production of extracellular inorganic pyrophosphate, an important inhibitor of nucleatio n and of the growth of apatite crystals. The ank gene product is one of sev eral cell membrane proteins, including ectonucleoside triphosphate pyrophos phohydrolase enzymes and alkaline phosphatase, that regulate extracellular inorganic pyrophosphate levels and thereby regulate mineralization.