Читать книгу Child Development From Infancy to Adolescence - Laura E. Levine - Страница 187

Given the toll that genetic disorders take on individuals, we continue to search for ways to treat these conditions. Scientists are working on ways to use our new knowledge about genes to prevent and treat human disorders, but gene therapy, the treatment of genetic disorders through the implantation or disabling of specific genes, is still in its infancy for humans. In 2017, the first three gene therapies were approved by the U.S. Food and Drug Administration for use in the United States (Goldschmidt & Scutti, 2017).

Gene therapy: Treatment of genetic disorders through implanting or disabling specific genes.

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Doctors are now able to treat many genetic disorders with gene therapy that involves changing the defective genes. False

Research on gene therapy took a great leap forward with the creation of the CRISPR program that allows for direct gene editing (Ledford, 2016). Scientists can now cut out sections of genes and turn off certain genes. This technology brings great hope that genetic disorders will become treatable or preventable through editing of the genes associated with them at some point in the future (Broad Institute, 2017). For example, using mice, CRISPR has been used to edit the genes associated with a disease called Duchenne muscular dystrophy (Bengtsson et al., 2017). With humans, a different approach is being tested to treat this disorder. UC Davis Health (2013) is currently studying a national sample of boys with this disease to assess the effectiveness of a drug designed to bridge over the defective gene to make it unreadable. These new approaches offer hope that genetic diseases can be prevented or treated.

Although we may not yet be able to change the genes themselves, we can sometimes control the effects of gene-based disorders through environmental interventions. For example, a child who has the disorder phenylketonuria (PKU) cannot produce an enzyme required for the digestion of phenylalanine, a common protein in foods such as beef, poultry, fish, eggs, milk, and wheat products (de Baulny, Abadie, Feillet, & de Parscau, 2007). When phenylalanine is only partially digested because of the missing enzyme, harmful substances are produced that can damage the child’s brain and central nervous system, resulting in intellectual disability (U.S. Library of Medicine, 2017b). The brain is particularly vulnerable to these damaging toxic effects in the early years when it is growing so rapidly. By eliminating phenylalanine from the diet of an infant through the use of a special formula, the harmful effects are avoided (Schuett, 2008). A low-phenylalanine diet then must be maintained throughout life to prevent the appearance of symptoms later in development (NHGRI, 2014). That diet primarily includes fruits, vegetables, and low-protein grain products. Although there are no comparable ways to negate the effects of gene-linked behavioral disorders such as attention deficit/hyperactivity disorder, depression, autism, or schizophrenia, there are many types of intervention that help mute the negative effects of these disorders and earlier intervention is often linked with a better outcome.