What Your Test Results Mean:

Risk for current and future pregnancies for fragile X syndrome and associated disorders is dependent on the length of the segment of your DNA known as the CGG triplet repeat. Genetic counseling is recommended.

Disease Explained:

Fragile X Explained

Approximately 1 in 4,000 males and 1 in 8,000 females have fragile X. The majority of males with fragile X have a significant intellectual disability. The spectrum ranges from learning disabilities to severe mental retardation and autism. About one third of the females with fragile X syndrome have a significant intellectual disability. Others may have more moderate or mild learning difficulties.

Fragile X Tremor Ataxia Syndrome (FXTAS)

Both male and female premutation carriers are at risk for developing a late onset (over 50) neurological condition called FXTAS. Individuals with FXTAS can develop trouble walking, leading to increased tendency to fall and subsequent dependence on walking aids. On average, male premutation carriers over age 50 have a 40% chance of developing FXTAS. The risk for female premutation carriers to develop FXTAS has not been defined; however, females seem to be at a lower risk of developing FXTAS when compared to males.

Fragile X-associated Primary Ovarian Insufficiency (POI)

Females who are premutation carriers are at an increased risk of developing Primary Ovarian Insufficiency (early menopause and reduced fertility, previously called POF). Approximately 1% of women in the general population develop Primary Ovarian I Insufficency (POI) while premutation carriers are estimated to have up to a 21% chance of developing POI. It is important to note that 5 to 10% of women with POI are able to conceive after receiving a diagnosis of POI.

How the Genetics Works:

The clinical features of fragile X-associated disorders can be explained by an expansion of a segment of DNA, known as the CGG triplet repeat, within the FMR1 gene. Generally, this DNA segment is repeated from 5 to about 40 times. In individuals with fragile X syndrome, however, the CGG segment is repeated more than 200 times. Males and females with 55 to 200 repeats of the CGG segment, also called permutation carriers, are at an increased risk to develop fragile X-associated primary ovarian insufficiency and/or fragile X-associated tremor/ataxia syndrome.