Fragile X Saskatchewan

What Is Fragile X?

Fragile X is a group of genetic conditions caused by a defect in the FMR1 gene on the X chromosome. This group of conditions includes:

Fragile X Syndrome (FXS) is the most common inherited cause of mental impairment and the most common known genetic cause of autism. This can range from learning disabilites to severe mental retardation. FXS was originally known as Martin-Bell syndrome. The actual gene that causes FXS was discovered in 1991. This gene, FMR1 (Fragile X Mental Retardation-1), is responsible for producing a protein that is required for normal neural development. With FXS the defect in this gene causes it to produce too little or none of the needed protein.

There are many physical and behavioural characteristics associated with Fragile X Syndrome. Physical problems can include ear infections, flat feet, double jointed-fingers, hyperflexible joints and a variety of skeletal problems. Behaviour characteristics include short attention span, speech disturbances, hand biting, hand flapping, autistic behaviours, social anxiety, unstable moods, and so forth.

FXS affects 1 in 4,000 boys and 1 in 6,000 girls. About 1 in 259 women carry fragile X and could pass it to their children. About 1 in 800 men carry fragile X; their daughters will also be carriers.

Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS) affects some older men (usually between ages 50-80) who are carriers. Although FXTAS can affect women carriers, it is rare. This is a condition that affects the neurologic system. Many common symptoms are action tremor, balance problems, Parkinson's-like symptoms, and memory/intellectuals decline. FXTAS may be misdiagnosed as Parkinson's or Alzheimer's disease.

Fragile X-Associated Primary Ovarian Insufficiency (FXPOI) affects approximately 20-28% of female carriers and is defined as menopause occuring prior to the age of 40. Another 23% of carriers will experience early menopause (menopause occuring prior to the age of 45). Although it is believed that all female carriers have some decrease in ovarian function, many women with permutations are able to conceive and family planning is recommended (instead of assuming decreased fertility). Furthermore, some female carriers are at an increased risk for depression and may have increased social anxiety.