New work by a pioneering scientist details how subtle changes in mitochondrial function may cause a broad range of common metabolic and degenerative diseases. Mitochondria are tiny energy-producing structures within our cells that contain their own DNA.
Fragile X syndrome is caused by a defect in a gene on the X chromosome called fragile X mental retardation 1 (FMR1). Around 1 in 230 women and 1 in 360 men carry a so-called premutation, in which a series of DNA repeats at one end of the FMR1 gene is slightly longer than normal. These repeats are prone to even further expansion when FMR1 is passed from mother to child, causing the gene to switch off and stop producing a protein that is important for some cognitive functions.