Genetic Disorders
Genetic Disorders, medical conditions caused by an error in a person’s genetic material. Some genetic disorders result in medical problems that are apparent at birth (see Birth Defects), while other genetic disorders do not become evident until childhood or adult life. Genetic disorders range in severity from those that cause death to those that produce only mild problems, such as color blindness. Scientists have identified more than 9,000 genetic disorders. Some of these disorders are extremely rare, while others are comparatively common.
Scientists have identified certain categories of genetic disorders, some of which have characteristic inheritance patterns. One category consists of single-gene disorders—disorders that involve an error in the DNA that makes up an individual gene. A second category of genetic disorders involves abnormalities of chromosomes in which too much or too little chromosomal material is present. Some genetic disorders are said to be multifactorial, because they are caused by the combined effects of multiple genes and environmental factors, such as diet and exposure to certain chemicals. Still other genetic disorders are caused by mutations in mitochondrial DNA.
Currently, there are no permanent cures for genetic disorders, but many treatments are available. A procedure called gene therapy is on the horizon; it may eventually provide permanent cures for at least some genetic disorders.
For a few genetic disorders caused by an enzyme malfunction, it is possible to replace the malfunctioning enzyme with a functioning enzyme. For example, Gaucher disease is an autosomal recessive disorder marked by a shortage of an enzyme called glucocerebrosidase. People with one type of Gaucher disease develop progressive bone disease and an enlarged spleen. They can be treated with enzyme replacement therapy, in which they receive regular intravenous infusions of synthetic enzymes that carry out the functions of glucocerebrosidase.
Most genetic disorders are treated using more than one type of treatment, in keeping with their complex and varied symptoms. For example, children with cystic fibrosis usually take pancreatic enzymes to help digest food and inhale medicines that are formulated to break up mucus in air passages. Parents of these children regularly clap their hand on the child’s chest and back to loosen mucus in the lungs. In some instances, surgeons may perform a lung transplantation to save a patient’s life.
Scientists have identified certain categories of genetic disorders, some of which have characteristic inheritance patterns. One category consists of single-gene disorders—disorders that involve an error in the DNA that makes up an individual gene. A second category of genetic disorders involves abnormalities of chromosomes in which too much or too little chromosomal material is present. Some genetic disorders are said to be multifactorial, because they are caused by the combined effects of multiple genes and environmental factors, such as diet and exposure to certain chemicals. Still other genetic disorders are caused by mutations in mitochondrial DNA.
Currently, there are no permanent cures for genetic disorders, but many treatments are available. A procedure called gene therapy is on the horizon; it may eventually provide permanent cures for at least some genetic disorders.
For a few genetic disorders caused by an enzyme malfunction, it is possible to replace the malfunctioning enzyme with a functioning enzyme. For example, Gaucher disease is an autosomal recessive disorder marked by a shortage of an enzyme called glucocerebrosidase. People with one type of Gaucher disease develop progressive bone disease and an enlarged spleen. They can be treated with enzyme replacement therapy, in which they receive regular intravenous infusions of synthetic enzymes that carry out the functions of glucocerebrosidase.
Most genetic disorders are treated using more than one type of treatment, in keeping with their complex and varied symptoms. For example, children with cystic fibrosis usually take pancreatic enzymes to help digest food and inhale medicines that are formulated to break up mucus in air passages. Parents of these children regularly clap their hand on the child’s chest and back to loosen mucus in the lungs. In some instances, surgeons may perform a lung transplantation to save a patient’s life.
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