3357
To discriminate variants of Pelizaeus - Merzbacher disease , a set of oligonucleotide primers was constructed to polymerase - chain - reaction ( PCR ) amplify and sequence the gene encoding proteolipid protein ( PLP ) , a structural protein that comprises half of the protein of the myelin sheath .
 Pelizaeus - Merzbacher disease
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Disease 
Text: {0} 
Answer:
 Pelizaeus - Merzbacher disease