What is the Mutation in FMR1 That Causes Fragile X Syndrome?
FMR1 (fragile X mental retardation 1) is the gene that contains the genetic information for how to synthesize FMRP (fragile X mental retardation protein). Fragile X syndrome occurs when FMRP is missing. The FMR1 gene is located in the DNA on the X chromosome. The specific location is given as Xq27.3. That means it is on the X chromosome (X), it is on the long arm (q) and it is at the far end (27.3). Genetic information in humans is stored in an odd way. Buried within the information that is actually used is lots of information that is not used. Imagine that you went to the library and found that in the chapter you were interested in, many of the pages contained random letters. You photocopied the entire chapter, including the pages that contained no useful information. Before you left the library, you tossed all the pages with random letters in a recycling bin and only took home the pages with words you could read. In a similar way, our genes are interspersed with spacers called intron
