Timing for Genotyping of Fragile X Syndrome

Fragile X syndrome (FXS) is the most common known cause of mental retardation and autism. The full mutation involves more than 200 CGG repeats of the FMR1 gene, resulting in uninhibited action by the metabotropic glutamate receptor mGlu5R (JW Psychiatry Feb 25 2008). Clinical diagnosis is confounded by the absence of specific phenotypic markers. To learn when diagnostic genotyping occurs and how the diagnosis affects families, including their reproductive planning, researchers contacted parents of children with FXS; names were obtained from foundations, researchers, and physicians. The researchers report on questionnaire results from the 249 families with a first child (213 boys) who had the full mutation and who was born between 2001 and 2…