Fragile X and autism: A multicenter survey

Abstract

We screened 183 autistic males for the fra(X) and found 24 (13.1%) to be positive. Adding the subjects of this study to those of 11 other surveys, of which 6 were positive and 5 were negative, a total of 614 autistic males have been screened. Overall 47 (7.7%) were positive. Based on this estimate and the prevalence of autism and fra(X), we estimate that 12.3% of fra(X) males are autistic. We have found that 17.3% of our fra(X) males were autistic and overall a 21.2% frequency has been reported, these higher figures are most likely due to biases in age and ascertainment. With an overall 7.7% frequency of fra(X) among autistic males and an estimated 12.3% of autism among fra(X) males, we conclude there is likely to be a significant association of fra(X) with autism. Because fra(X) appears to be the single most common cause of the condition, chromosomal testing is recommended for any autistic person with undiagnosed etiology.

Fragile X syndrome

“…Autistic-like features are common in individuals with FXS and include hand flapping, hand biting, gaze avoidance, tactile defensiveness, and hyperarousal to sensory stimuli. 15,16 These features -along with impaired social skills, such as socio-emotional reciprocityare expressed with varying degrees in children with FXS and may be indicative of a concurrent diagnosis of autism spectrum disorder or autistic-like behavior. 17 Anxiety and mood disorders, hyperactivity, impulsivity, and aggressive behavior can also be present.…”

The cyclic AMP phenotype of fragile X and autism

“…The high comorbidity of autism and FX (Brown, Jenkins et al 1982;Brown, Jenkins et al 1986;Loesch, Bui et al 2007) warrants a discussion of cAMP function in autism. To date, no studies of the neuronal cAMP cascade are available in autism or autism comorbid with FX.…”

“…FX premutation carriers have more than 55 CGG repeats and those with more than 200 repeats have a full FX mutation (Fu, Kuhl et al 1991). The comorbidity of autism and FX was initially reported to be around 18% (Brown, Jenkins et al 1982) and a lower percentage of those with autism have FX (about 7%) (Brown, Friedman et al 1982;Brown, Jenkins et al 1986;Loesch, Bui et al 2007). Although reported incidences vary, FX is known to be the most common inherited cause of autism.…”

PresynapticFmr1Genotype Influences the Degree of Synaptic Connectivity in a Mosaic Mouse Model of Fragile X Syndrome

“…FXS patients suffer mental retardation, macroorchidism, facial dysmorphologies, and behavioral problems (Hagerman, 2002) as well as a high incidence of epilepsy (Musumeci et al, 1999). Because a small but significant proportion of children with autism spectrum disorder (ASD) have a mutation in the FMR1 gene (Brown et al, 1986) and up to 33% of children with FXS fulfill a diagnosis of autism (Rogers et al, 2001), FXS is considered to be a genetic model of ASD (Hagerman et al, 2005).…”