the importance of diagnosis

The importance of diagnosing the Fragile X child early is two-fold. Firstly, there are many relatives who are at risk of having affected children who could benefit from genetic counselling, carrier testing and the offer of pre-natal diagnosis. Secondly, the child concerned can receive specialist help in areas of education, speech and language development and behaviour modification. Adults with Fragile X have specific problems too the understanding and management of which can be helped once their diagnosis is known.

Too few people have heard of Fragile X and still many doctors know little about it. Parents, when told they have a child with Fragile X can experience a sense of isolation and ignorance. The Irish Fragile X Society hopes to provide support for parents during this sensitive time. Our Information pack is available to you at no cost, by contacting us via post or e-mail.

Prevalence

Based on the best available evidence:

Approximately 1 in 3600 to 4000 males in the world are born with the full mutation for Fragile X. The vast majority of males with the full mutation will have an intellectual disability.
Approximately 1 in 4000 to 6000 females in the world are born with the full mutation for Fragile X. About 50% of females with the full mutation will have some features of fragile X syndrome and a varying degree of intellectual disability.
Approximately 1 in 800 men in the world are carriers of the Fragile X pre-mutation.
Approximately 1 in 260 women in the world are carriers of the Fragile X pre-mutation. (Though a recent 2004 analysis, noted below, suggests that the figure could be as high as 1 in 130.)

For more information about the differences between the pre-mutation and full mutation please use this link: http://www.fragilex.org/html/carriers.htm

In 2004-2005, The National Fragile X Foundation (http://www.nfxf.org) funded a comprehensive analysis of all known Fragile X prevalence studies, by a noted statistician, Dr. Laurel Beckett at UC Davis, California. A summary of that paper was published in the National Fragile X Foundation's September 2005 issue of the Foundation Quarterly Journal. That summary is available here: Prevalence White Paper Adapted for Foundation Quarterly. (The full paper is being submitted to a peer-reviewed journal.)

In 2001 the Centers for Disease Control (CDC) produced a prevalence analysis (which was included in Dr. Beckett's analysis). To view the CDC report, visit http://www.cdc.gov/genomics/hugenet/factsheets/FS_FragileX.htm