According to new research clues to Fragile X syndrome may be connected to one single human gene.
Fragile X syndrome is the most common inherited cause of mental retardation and autism and affects 90,000 to 100,000 Americans.
Fragile X syndrome can cause seizures, impaired memory, learning disabilities, hyperactivity, severe mental retardation and accelerated body growth.
It is a genetic disorder caused by mutation of the FMR1 gene on the X chromosome.
Apart from intellectual disability, prominent characteristics of the syndrome include an elongated face, large or protruding ears, flat feet, larger testicles in men and low muscle tone; speech too may be affected and may include cluttered or nervous speech.
Behaviour may include stereotypic movements such as hand-flapping and poor social development, particularly shyness and limited eye contact and some individuals with the fragile X syndrome also meet the diagnostic criteria for autism.
Fragile X syndrome is more common in males often resulting in severe intellectual disability but while most females experience symptoms to a lesser degree they too can develop just as severe symptoms.
There is no current cure for the syndrome which is commonly treated with behavioral therapy, special education, medication, and when necessary, treatment of physical abnormalities.
Researchers at the Picower Institute for Learning and Memory at the Massachusetts Institute of Technology conducted a study using mice and found that with genetic engineering they were able to alter the gene in mice which caused the worst symptoms of Fragile X syndrome.
The researchers say their findings support the theory that many of the symptoms of Fragile X stem come from too much activation of one of the brain's chief network managers, a protein called the metabotropic glutamate receptor or mGluR5.
FMRP and mGluR5 control one another and when a mutation cuts out FMRP, mGluR5 signals run rampant.