1073
Previously identified mutations in this variant have been within or close to the coding region of exon 1 of the HMBS gene , the only exon that is expressed solely in the ubiquitous isoform .
 GENE: HMBS gene
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: HMBS gene