Genetic Testing

Presymptomatic testing of children has somewhat different considerations. It is typically considered only when the onset of the disorder occurs in childhood, or when knowing the genetic status will significantly benefit the child, for example by enabling him to receive early preventive treatment. For example, children at risk for inheriting the gene that causes retinoblastoma (cancer of the retina) may be tested because the disease usually presents before age five. With early treatment, the long-term outcome is favorable. Knowing whether the child has inherited the gene will allow physicians to know whether to aggressively screen the child for signs of cancer development.

Many genetic professional organizations have developed position statements regarding genetic testing of children that discourage testing for disorders that do not pose a risk in childhood and for which early identification poses no benefit to the child. This includes adult-onset disorders, such as Huntington's disease, but also pertains to carrier testing of females for X-linked recessive disorders, such as muscular dystrophy. In most X-linked (sometimes referred to as sex-linked) recessive disorders, females who inherit a mutation on one of their two X chromosomes are usually unaffected carriers because the second X chromosome is able to compensate for the loss. However, because males have only one X chromosome (the other sex chromosome is a Y), they will be affected if they inherit a mutation. In genetic medicine, personal autonomy is a priority. Individuals have the right to make their own decision regarding genetic testing. If a child is tested for an adult-onset disorder or to determine carrier status, their right to make their own decision as an adult has essentially been taken away.