Congenital disorder

A congenital disorder is a medical condition that is present at birth. A congenital disorder can be recognized before birth (prenatally), at birth, or many years later. Congenital disorders can be a result of genetic abnormalities, the intrauterine environment, or unknown factors. A congenital condition can arise from the genetic make-up of the fertilized egg or be acquired at any time during fetal development. The causes of many congenital disorders are not known.

Related Topics:
Congenital disorder - Birth - Genetic - Environment - Fertilized egg - Fetal development

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Congenital disorders include minor physical anomalies (e.g., a birthmark), severe malformations of single systems (e.g., congenital heart disease or amelia of the legs), and combinations of abnormalities affecting several parts of the body. Defects of metabolism are also considered congenital disorders. A congenital disorder can have trivial or grave effects. The most severe, such as anencephaly, are incompatible with life.

Related Topics:
Birthmark - Heart disease - Amelia - Anencephaly

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About 2-3% of babies are born with significant congenital birth defects. By organ system, birth defects involving the brain are the largest group at 10 per 1000 live births), compared to heart at 8 per 1000, kidneys at 4 per 1000, and limbs at 2 per 1000. All other defects have a combined incidence of 6 per 1000 live births.

Related Topics:
Brain - Heart - Kidney - Limb

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About 25% of birth defects result from genetic abnormalities. About 5% involve abnormalities of large portions or entire chromosomes. Some congenital disorders arise from inheritance of abnormal genes from the parents but some can arise from a new mutation in one of the germ cells that contributed to the fetus.

Related Topics:
Genetic - Chromosome - Inheritance - Gene - Mutation - Germ cell

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Influences of the intrauterine environment of the fetus which can cause birth defects are referred to as teratogenic. These can include dietary deficiencies, toxic effects, or infections. For example, dietary deficiency of maternal folic acid is associated with spina bifida. Exposure to harmful substances during pregnancy (e.g, mercury) or maternal drugs (e.g., phenytoin) can cause recognizable combinations of birth defects. Many infections which a mother can contract during pregnancy, such as rubella and syphilis, can also affect the baby.

Related Topics:
Teratogenic - Folic acid - Spina bifida - Mercury - Phenytoin - Rubella - Syphilis

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A significant proportion of birth defects cannot be attributed to either genetic abnormalities or environmental exposures. These are referred to as sporadic birth defects, a term which implies an unknown cause, random occurrence, and a low recurrence risk for future children.

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