Genetic Testing and an Autism Spectrum Disorder

Scientists and physicians know that an autism spectrum disorder can occur in families. Siblings of people on the autism spectrum are more likely to be autistic, and twins are extremely likely to share autistic traits. This means there is almost certainly a genetic component of an autism spectrum disorder. However, this does not mean that a single gene is responsible or that genetics is the only factor in causing an autism spectrum disorder. Most researchers believe that a combination of several genetic differences, possibly combined environmental factors, may lead to an autism spectrum disorder.

Genetic Testing

Genetic testing looks for mutations in genes inherited from biological parents. Genetic testing is usually performed on DNA obtained from a small sample of your blood. Most genes come in a number of variant forms, known as alleles. For example, the section of DNA for eye color may have two different versions, or alleles, one for blue eyes and one for brown. One of these versions is labeled dominant and the other is recessive. A dominant allele, by definition, prevails over a recessive allele.

Genes, through the proteins they encode, control all bodily processes, including how the body responds to challenges from the environment. Such challenges include how efficiently we process foods, how effectively we our bodies get rid of poisons, and how quickly we respond to infections. More than 4,000 diseases are thought to stem from mutated (altered or changed) genes inherited from the mother and/or father. Some mutations are silent and do not affect either the structure of the encoded protein or its function. Each cell has a remarkable ability to recognize mistakes and fix them before they can be inherited by future generations. However, a cell’s DNA repair systems can fail, be over worked, or become less efficient with age. Due to the fact that autism spectrum disorders are highly heritable, but not inherited, genetic testing can be used to look for suspected mutations in an individual or family.

There are limitations of gene testing because a single gene can have numerous mutations, and not all of them are likely to be equally influential. Despite major advances in DNA analysis technology, identifying mutations that cause a specific disease or disorder remains a great challenge. Many of the genes of the greatest interest to researchers are enormous and contain thousands of bases. Mutations can occur anywhere and searching through long stretches of DNA is difficult. In some cases, a positive genetic test does not guarantee that you will get a disease, while a negative test cannot completely rule out that you will never get a certain disease.

Ethics related to genetic testing for an autism spectrum disorder

Genetic testing for autism spectrum disorders can help parents with a child on the autism spectrum to determine their risk of having a second child with an autism spectrum disorder. It also might allow for an earlier diagnosis and intervention program.The purpose of an early intervention program is to find and treat children who are at risk of disability or delay at a very young age. Studies suggest that early intervention programs can significantly improve outcomes for children with an autism spectrum disorder.

Genetic testing is a difficult emotional process that can be life changing. There are emotions that surface when a person learns that they are likely to develop a serious disease or condition. This can cause a person to feel scared, sad, and depressed. It can also cause these feelings in their loved ones. Moms and dads might feel guilty and think that they gave their child a disease. Some family members might be angry to find out they carry the gene for a certain disease, especially if they didn’t want to know at all. This news might cause unnecessary fear particularly if the person has the gene and doesn’t develop the disease or condition.

The prospect of prenatal or gentic testing of embryos for ASDs raises serious ethical concerns related to the elimination of ASD traits.  Some argue that ASDs- especially Asperger’s and more mild forms of autism– are personality types that ought not be considered disorders at all.  Many people worry that genetic tests that single out ASD markers will inevitably devalue such personality types.

by HSBioethics

Sources:

http://www.cdc.gov/ncbddd/autism/index.html

http://www.ninds.nih.gov/disorders/autism/detail_autism.htm

Related Articles:

Complete List of All Articles on Autism Spectrum Directory

Genetics of Autism

An Individual’s Worth

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