congenital

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Congenital

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Congenital describes a condition or defect that exists at birth. Congenital disorders are inborn; they are present in the developing fetus. Sickle cell disease, Down syndrome, and congenital rubella syndrome are three examples of congenital conditions in humans. Congenital disorders result from abnormalities in the fetuss genetic inheritance, conditions in the fetal environment, or a combination of the two. Two to three percent of babies in the United States are born with a major congenital defect. Prenatal testing can detect some congenital conditions.

Many congenital conditions are caused by chromosomal disorders. A human fetus inherits 23 chromosomes from its mother and 23 chromosomes from its father, making a total of 23 pairs. An extra or missing chromosome creates havoc in fetal development. Down syndrome, marked by mental retardation and a distinctive physical appearance, is caused by an extra chromosome.

Each chromosome carries many genes. Like chromosomes, genes are present in pairs. Genes are responsible for many inherited traits, including eye color and blood type. Genetic disorders are caused by abnormal genes. Sickle cell disease, a blood disorder, occurs when a fetus inherits an abnormal gene from each parent. Polydactyly, the presence of extra fingers or toes, occurs when an abnormal gene is inherited from one parent.

Some congenital disorders are caused by environmental factors. Certain genetic combinations may make some fetuses more vulnerable to the absence or presence of certain nutrients or chemicals. Spina bifida, also known as open spine, occurs when embryo development goes awry and part of the neural tube fails to close. Adequate amounts of folic acid, a vitamin, help prevent spina bifida. Cleft palate, a hole in the roof of the mouth, is another congenital defect that seems to be caused by multiple factors. Congenital rubella syndrome, marked by mental retardation and deafness, is present in newborns whose mothers contracted rubella (German measles) during pregnancy.

Prenatal testing can diagnose certain congenital disorders. Ultrasound, which uses sound waves to produce an image of the fetus, can discover some defects of the heart and other organs. Amniocentesis and chorionic villi sampling are procedures that remove fetal cells from the pregnant uterus for genetic testing. These tests can determine the presence of Down syndrome, sickle cell anemia, cystic fibrosis, and other genetic diseases. Couples may choose to terminate the pregnancy if serious abnormalities are discovered.

See also Birth defects; Embryo and embryonic development.

Resources

BOOKS

Davis, Joel. Mapping the Code. New York: John Wiley & Sons, 1990.

Edelson, Edward. Birth Defects. New York: Chelsea House Publishers, 1992.

Marshall, Liz. The Human Genome Project: Cracking the Code Within Us. Brookfield, CT: Millbrook Press, 1995.

Planning for Pregnancy, Birth, and Beyond. Washington, DC: American College of Obstetricians and Gynecologists, 1990.

Wills, Christopher. Exons, Introns, and Talking Genes. New York: Basic Books, 1991.

OTHER

Loma Linda University Childrens Hospital. Pediatric Surgery: Congenital Disorders <http://www.llu.edu/lluch/pedsurg/congenital.html> (accessed November 16, 2006).

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Congenital

The term congenital is used to describe a condition or defect that exists at birth . Congenital disorders are inborn. They are present in the developing fetus. Sickle cell disease, Down syndrome , and congenital rubella syndrome are three examples of congenital conditions in humans. Congenital disorders result from abnormalities in the fetus's genetic inheritance, conditions in the fetal environment, or a combination of the two. Two to three percent of babies in the United States are born with a major congenital defect. Prenatal testing can detect some congenital conditions.

Many congenital conditions are caused by chromosomal disorders. A human fetus inherits 23 chromosomes from its mother and 23 chromosomes from its father, making a total of 23 pairs. An extra chromosome or a missing chromosome creates havoc in fetal development. Down syndrome, marked by mental retardation and a distinctive physical appearance, is caused by an extra chromosome.

Each chromosome carries many genes. Like chromosomes, genes are present in pairs. Genes are responsible for many inherited traits, including eye color and blood type. Genetic disorders are caused by abnormal genes. Sickle cell disease, a blood disorder, occurs when a fetus inherits an abnormal gene from each parent. Polydactyly, the presence of extra fingers or toes, occurs when an abnormal gene is inherited from one parent.

Some congenital disorders are caused by environmental factors. It may be that certain genetic combinations leave some fetuses more vulnerable to the absence or presence of certain nutrients or chemicals. Spina bifida , also known as "open spine," occurs when embryo development goes awry and part of the neural tube fails to close. Adequate amounts of folic acid, a vitamin , help prevent spina bifida. Cleft palate, a hole in the roof of the mouth, is another congenital defect that seems to be caused by multiple factors. Congenital rubella syndrome, marked by mental retardation and deafness, is present in newborns whose mothers contracted rubella (German measles) during pregnancy.

Prenatal testing can diagnose certain congenital disorders. Ultrasound, which uses sound waves to produce an image of the fetus, can discover some defects of the heart and other organs. Amniocentesis and chorionic villi sampling are procedures that remove fetal cells from the pregnant uterus for genetic testing . These tests can determine the presence of Down syndrome, sickle cell anemia , cystic fibrosis , and other genetic diseases. Couples may choose to terminate the pregnancy if serious abnormalities are discovered.

See also Birth defects; Embryo and embryonic development.


Resources

books

Davis, Joel. Mapping the Code. New York: John Wiley & Sons, 1990.

Edelson, Edward. Birth Defects. New York: Chelsea House Publishers, 1992.

Marshall, Liz. The Human Genome Project: Cracking the CodeWithin Us. Brookfield, CT: Millbrook Press, 1995.

Planning for Pregnancy, Birth, and Beyond. Washington, DC: American College of Obstetricians and Gynecologists, 1990.

Wills, Christopher. Exons, Introns, and Talking Genes. New York: Basic Books, 1991.

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con·gen·i·tal / kənˈjenətl/ • adj. (esp. of a disease or physical abnormality) present from birth. ∎  (of a person) having a particular trait from birth or by firmly established habit: a congenital liar. DERIVATIVES: con·gen·i·tal·ly adv.

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congenital Present at birth. Congenital disorders of the body may be due to genetic factors, e.g. Down's syndrome, or caused by injury or environmental factors, e.g. drugs (such as thalidomide), chemicals (such as dioxin), and infections (such as those caused by Listeria and cytomegalovirus).

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congenital dating from one's birth. XVIII. f. L. congenitus born along with, connate, f. CON- +genitus, pp. of gignere produce (see GENITAL).

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congenital (kŏn-jen-it'l) adj. describing a condition that is recognized at birth or that is believed to have been present since birth. Congenital malformations include all disorders present at birth whether they are inherited or caused by an environmental factor.

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congenital Existing at birth; applied to inherited traits that become apparent only during growth.

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congenital Existing at birth; applied to inherited traits that become apparent only during growth.