A nucleotide change could initiate fragile X syndrome

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.

NIH Undiagnosed Diseases Program

The Undiagnosed Diseases Program at the National Institutes of Health (NIH) is a project that is designed to advance the field of knowledge around rare and common diseases.

DNA Double Take

Scientists are discovering that — to a surprising degree — we contain genetic multitudes. Not long ago, researchers had thought it was rare for the cells in a single healthy person to differ genetically in a significant way. But scientists are finding that it’s quite common for an individual to have multiple genomes. Some people, for example, have groups of cells with mutations that are not found in the rest of the body. Some have genomes that came from other people.

Science surprise: Toxic protein made in unusual way may explain brain disorder

The condition, called Fragile X-associated Tremor Ataxia Syndrome (FXTAS), causes shakiness and balance problems and is often misdiagnosed as Parkinsons disease. The grandchildren of people with the disease have a separate disorder called Fragile X syndrome, caused by problems in the same gene. The new discovery may also help shine light on that disease, though indirectly.

Scientists create 1-step gene test for mitochondrial diseases

"A first step in developing treatments for a disease is to understand its precise cause," said Marni J. Falk, M.D., the director and attending physician in the Mitochondrial-Genetic Disease Clinic at Children's Hospital. "We have developed a one-step, off-the-shelf tool that analyzes both nuclear and mitochondrial DNA to help evaluate the genetic cause of suspected mitochondrial disease."