3902
Hypoxanthine - guanine phosphoribosyltransferase ( HPRT ; EC2 . 4 . 2 . 8 ) , which functions in the metabolic salvage of purines , is encoded by an X - linked gene in man .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease 
Text: {0} 
Answer:
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