Sally Zahra

Assessment of Hair Aluminum, Lead, and Mercury in a Sample of Autistic Egyptian Children: Environmental Risk Factors of Heavy Metals in Autism

Background and Aims. The etiological factors involved in the etiology of autism remain elusive and controversial, but both genetic and environmental factors have been implicated. The aim of this study was to assess the levels and possible environmental risk factors and sources of exposure to mercury, lead, and aluminum in children with autism spectrum disorder (ASD) as compared to their matched controls. Methods. One hundred ASD children were studied in comparison to 100 controls. All participants were subjected to clinical evaluation and measurement of mercury, lead, and aluminum through hair analysis which reflects past exposure. Results. The mean Levels of mercury, lead, and aluminum in hair of the autistic patients were significantly higher than controls. Mercury, lead, and aluminum levels were positively correlated with maternal fish consumptions, living nearby gasoline stations, and the usage of aluminum pans, respectively. Conclusion. Levels of mercury, lead, and aluminum in the hair of autistic children are higher than controls. Environmental exposure to these toxic heavy metals, at key times in development, may play a causal role in autism.

Screening of Egyptian toddlers for autism spectrum disorder using an Arabic validated version of M-CHAT; report of a community-based study (Stage I).

BACKGROUND Although there is a recommendation that toddlers be screened for Autism spectrum disorder (ASD) during their 18- and 24-month well-care child visits, diagnosis often occurs well after the child turns 4 years old. Such delayed diagnosis hinders the implementation of early intervention thus worsens the long-term prognosis of ASD. OBJECTIVE The current community-based study in its stage I aimed at early screening of Egyptian toddlers for ASD using an Arabic validated version of Modified Checklist for Autism in Toddlers (M-CHAT). METHODOLOGY A cross-sectional community-based descriptive study was carried out enrolling 5546 Egyptian toddlers. They were randomly recruited from those attending Primary Health Care Units in six Egyptian governorates with a fair representation of the urban, semi-urban, and rural Egyptian populations. An Arabic validated version of M-CHAT was used as a screening tool for ASD. RESULTS The current study revealed failure of M-CHAT (suspected to have ASD and needs further evaluation) in 1320 out of the enrolled 5546 Egyptian toddlers (23.8%). CONCLUSION M-CHAT as a screening tool for ASD has flagged a considerable percent of the enrolled toddlers that necessitates referral for further evaluation (stage II) to settle the diagnosis of ASD in the true positive cases. Perfecting the delicate balance between sensitivity and specificity for ASD screening tools is crucial in order not to miss early detection of ASD cases and at the same time, to avoid over-diagnosis with subsequent abuse of the limited healthcare resources in developing countries.

Dopamine D4 Receptor Gene Polymorphism in a Sample of Egyptian Children With Attention-Deficit Hyperactivity Disorder (ADHD):

This study aimed to detect DRD4 receptor gene polymorphisms in attention-deficit hyperactivity disorder (ADHD) children and to correlate their phenotype-genotype. Fifty children with ADHD were diagnosed by Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria and were subjected to Conners Parent Rating Scale. All cases and controls were subjected to history taking, physical examination, IQ assessment, and dopamine receptor D4 (DRD4) exon 3 genotyping. The 7-repeat allele was present only in controls, whereas 2-repeat allele was present in the ADHD children (heterozygous 2-repeat allele in 16% and homozygous in 26% of cases). Eight percent of cases had homozygous 4-repeat allele vs 28% of controls, whereas 10% of cases had heterozygous 4-repeat allele vs 6% of controls, with its predominance in controls. The 2-repeat and 4-repeat alleles have been associated with more inattention, hyperactivity, and impulsivity phenotypes. In conclusion, children with ADHD had a significant presence of the 2-repeat allele and absence of the 7-repeat allele.