18356
Functional ablation of tissue - nonspecific alkaline phosphatase ( TNAP ) ( Alpl ( - / - ) mice ) leads to hypophosphatasia , characterized by rickets / osteomalacia attributable to elevated levels of extracellular inorganic pyrophosphate , a potent mineralization inhibitor .
 pyrophosphate
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 pyrophosphate