Fragile X Syndrome and Autism Research

Meguid first discovered the prevalence of fragile X mutation among Egyptian males. The mutation occurred 0.9 per 1000 Egyptian males.^[4] There was a 6.4% prevalence that the mutation would occur in males who were mentally subnormal. Meguid determined that the high prevalence of fragile X in Arab mentally subnormal males may be a result of awareness or diagnoses of the disease. Egyptian males had a late recognition of this genetic mutation past their childhood. The genetic mutations could be predicted as the disease was related to an increased percentage of consanguineous marriages in the Arab population. A delayed awareness of the genetic mutation was also a common cause of other disorders related to mental subnormality. Meguid concluded that the high prevalence of fragile X syndrome should promote special education for those affected. She suggested that an individualized treatment plan starting in preschool could allow students to be more successful in their educational years.

Meguid analyzed brain morphology in both fragile x syndrome with autistic features and autism patients and determined if there are any significant differences in the genetic disorders.^[5] 1.5-T magnetic resonance imaging (MRI) was used. No significant differences were found in brain morphology including "total brain volume, regional volume, gyrification index, sulcal depth, and cerebral cortical thickness." Autistic patients had a decrease in the medial prefrontal bilaterally and left anterior cingulate cortices of the brain. The medial prefrontal and the anterior cingulate were found to be significant in social cognition and autistic and fragile X patients were deficient in both. The deficiency in brain morphological features accounted for a social cognitive deficit. Fragile X with autistic features reflected selectively higher scores on social withdrawal scales - deficits were significantly different than those of autistic individuals. Fragile X autistic characteristics were shared with that of idiopathic autism however.

Meguid developed a simple molecular screening method to detect premutation carriers of fragile X syndrome. A premutation carrier is an individual who has between 55-200 CGG repeats in the Fragile X (FMR1) gene. The full mutation has over 200 CGG repeats. The procedure included a rapid modified polymerase chain reaction (PCR)-based screening tool for expanded Fragile X Mental Retardation 1 (FMR1) alleles.^[6] The results showed that 16 males out of 53 males had the CGG abnormal repeats characteristic of Fragile X gene. 10 of their mothers and 4 of their sisters also had the FMR1 premutation. 66.6% consanguineous marriages were present in the families studied. It was concluded that fragile X syndrome was ruled out of families with consanguineous parents. Instead, fragile X syndrome could be contributed to earlier carrier detection, which may reduce the number of affected children. By isolating the mutation early, the effects of the disease could be reduced in children and in their development.

Discoveries of Genetic Mutations