Fragile X syndrome (FXS) is the most common form of genetic mental disability. It occurs in about one of every 3,600 male children and one in every 4,000 to 6,000 females. Previous medical research has pinpointed the part of the cell affected by FXS but a new study reveals how the problem occurs. Knowing the mechanisms behind the disease could lead to treatment breakthroughs that target only the part of the cell that goes awry.

Simpson Joseph, professor of chemistry and biochemistry at the University of California, San Diego (UCSD), led the study involving researchers from UCSD as well as collaborators from the State University of New York and the New York State Department of Health.

What's been previously known is that a specific protein — the fragile X mental retardation protein (FMRP) — is deficient in people with the disease. The protein affects parts of a cell called ribosomes. Each cell has many ribosomes, which link together amino acids, the building blocks of proteins.  

There are subunits within each ribosome. The UCSD study showed how the FMRP protein binds itself to the region of the ribosome between its subunits.

The UCSD researchers suspect the region between ribosome subunits is where the FMRP protein attaches itself is where proteins that govern normal cognitive function are created. Its presence there is thought to alter gene expression in that location in ways that create faulty proteins for cognitive development.

Further study is required before the knowledge gained in the UCSD study can be converted into market-ready pharmaceuticals to treat fragile X syndrome. The study involved fruit flies, not humans, because the ribosomes and FMRP protein in fruit flies are similar to that of humans.

Joseph says it's also possible that other proteins within a cell work in similar fashion to the FMRP, binding to the ribosome in ways that regulate or alter gene expression. Further research targeting these particular areas of the cell is in order.

The UCSD study was funded with grants from the National Institutes of Health. The findings of the study are scheduled for publication in the May 2014 issue of the journal, Molecular Cell.

Source: McDonald, Kim. "Discovery Could Lead to Novel Therapies for Fragile X Syndrome." UC San Diego News Center. Regents of the University of California. Apr 17, 2014. Web. Apr 30, 2014.