579
The 24 exons of BRCA1 span an 81 - kb region that has an unusually high density of Alu repetitive DNA ( 41 . 5 % ) , but relatively low density ( 4 . 8 % ) of other repetitive sequences .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease 
Text: {0} 
Answer:
 None