The most common inherited form of mental retardation, fragile X syndrome, continues to baffle researchers even though the mutant gene responsible for the condition was identified a decade ago.
Now, several research groups are unraveling how this single flawed gene on the X chromosome alters a cell's use of protein-building instructions from dozens, even hundreds, of other genes. The new findings could lead to ways of counteracting those changes and reducing some symptoms of fragile X syndrome.
The master gene behind the syndrome encodes a protein–called FMRP, for fragile X mental retardation protein–that binds to strands of messenger RNA (mRNA). These strands are intermediaries between genes and the proteins they encode: Cells read a gene's DNA to make an mRNA and then use it to build the protein.
Neuroscientists have theorized that fragile X syndrome results when FMRP doesn't properly ferry mRNAs within cells, particularly in brain cells, or fails to