Autism Spectrum Disorder-associated Biomarkers for Case Evaluation and Management by Clinical Geneticists

David A. Geier; Mark R. Geier


Expert Rev Mol Diagn. 2008;8(6):671-674. 

In This Article

Genetic Biomarkers

Multiple lines of epidemiologic evidence support the strong role of genetics in the etiology of ASDs. Some of the most frequently reported chromosome regions with abnormalities associated with ASDs include 15q pericentromeric 11–13 region, 17p11, 22q11, 22q13, 16p11.2 and 2q37. Currently, array comparative genomic hybridization has emerged as a powerful new tool that promises further revolution of clinical genetic testing. In addition, Fragile X syndrome and mutations in the MECP2 gene are reported in ASDs.[6]

Other investigators have described the recently emerging importance of evaluating MTHFR gene mutations (i.e., polymorphisms) in ASDs.[24,43] The MTHFR gene codes for an essential enzyme in folate metabolism. MTHFR enzyme catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. Methyltetrahydrofolate is essential in one-carbon-donor metabolism for the remethylation of homocysteine to methionine and the generation of metabolically active tetrahydrofolate in the methionine synthase reaction. Common SNPs of the C677T and the A1298C alleles in the MTHFR gene decrease the activity of the enzyme, and have been observed to occur at a significantly higher rate among ASDs in comparison with controls.[24,43]

Genetic biomarkers are available from LabCorp, which offers blood chromosome (Test#052019), chromosome microarray (Test#510002), DNA Rett syndrome (Test#511180), Angelman/Prader Willi syndrome methylation assay (Test#511210), Fragile X syndrome (Test#510065) and MTHFR (Test#511238) testing. Genetic abnormalities are common among ASDs. Therefore, it is important that affected families seek genetic counseling to determine the family risk of transmission of ASD-associated genes, as well as to provide insights into behavior modification in order to help reduce the impact of genetic polymorphisms.


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