A congenital disorder is a medical condition that is present at birth. (It is contrasted with the term "acquired disorder") 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 disease is any abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person affected or those in contact with the person. ... Childbirth (also called labour, birth, partus or parturition) is the culmination of a human pregnancy with the emergence of a newborn infant from its mothers uterus. ... An acquired disorder is a medical condition which develops post-fetally; in contrast with a congenital disorder, which is present at birth. ... Prenatal means before birth (is widely used in biology). ... Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ...

Terminology

Congenital disorders is a broad category that includes a variety of conditions. The following terms are used for various subsets of congenital disorders:

• Birth defect is a widely-used term for a structural malformation of a body part, recognizable at birth, which is significant enough to be considered a problem.

• A congenital physical anomaly is a difference, an abnormality, of the structure of a body part. An anomaly may or may not be perceived as a problem condition. Many, if not most, people have one or more minor physical anomalies if examined carefully. Examples of minor anomalies can include curvature of the 5th finger (clinodactyly), tiny indentations of the skin near the ears (preauricular pits), shortness of the 4th metacarpal or metatarsal bones, or dimples over the lower spine (sacral dimples). Some minor anomalies may be clues to more significant internal abnormalities.

• A congenital malformation is a deleterious physical anomaly, a structural defect perceived as a problem. A recognizable combination of malformations or problems affecting more than one body part is referred to as a malformation syndrome.

• Genetic diseases or disorders are all congenital, though they may not be expressed or recognized until later in life. Genetic diseases may be divided into single-gene defects, multiple-gene disorders, or chromosomal defects. Single-gene defects may arise from abnormalities of both copies of an autosomal gene (a recessive disorder) or of only one of the two copies (a dominant disorder). Some conditions result from deletions or abnormalities of a few genes located contiguously on a chromosome. Chromosomal disorders involve the loss or duplication of larger portions of a chromosome (or an entire chromosome) containing hundreds of genes. Large chromosomal abnormalities always produce effects on many different body parts and organ systems.

• A congenital metabolic disease is also referred to as an inborn error of metabolism. Most of these are single gene defects, usually heritable. Many affect the structure of body parts but some simply affect the function.

Congenital conditions can be referred to as diseases, defects, disorders, anomalies, or simply genetic differences. The usage overlaps, but also involves a value judgement as to the harmfulness of the condition. In particular, people may disagree as to whether a specific condition should be considered a birth defect or a minor congenital anomaly. See human variability and disease for more on the occasional difficulties of drawing these distinctions. The metacarpus is the intermediate part of the hand skeleton that is located between the fingers distally and the carpus which forms the connection to the forearm. ... The metatarsus consists of the five long bones of the foot, which are numbered from the medial side (ossa metatarsalia I.-V.); each presents for examination a body and two extremities. ... A sacral, or pilonidal dimple is a small hole located just above the buttocks. ... In medicine, the term syndrome is the association of several clinically recognizable features, signs, symptoms, phenomena or characteristics which often occur together, so that the presence of one feature alerts the physician to the presence of the others. ... A genetic disorder, or genetic disease is a disease caused, at least in part, by the genes of the person with the disease. ... An autosome is a non-sex chromosome. ... In genetics, the term recessive gene refers to an allele that causes a phenotype (visible or detectable characteristic) that is only seen in a homozygous genotype (an organism that has two copies of the same allele). ... The word dominant has several possible meanings: In music theory, the dominant or dominant note (second most important) of a key is that which is a perfect fifth above the tonic; in just intonation the note whose pitch is 1. ... Inborn errors of metabolism comprise a large class of genetic diseases involving disorders of metabolism. ... Human variability, or human variation, refers to the range of possible values for any measurable characteristic, physical or mental, of human beings. ... A disease or medical condition is an abnormality of the body or mind that causes discomfort, dysfunction, distress, or death to the person afflicted or those in contact with the person. ...

Severity range

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. Birth defects are a leading cause of death in early infancy, accounting for the deaths of nearly 2 out every 1000 infants (US statistics). A birthmark, is a blemish on the skin formed before birth. ... Heart disease is one of a number of different diseases which afflict the heart. ... Amelia is the birth defect of lacking one or more limbs. ... This article or section does not cite its references or sources. ...

Other types are: polydactyly, polymelia, achrondroplasia, cleidocranial dysostosis, phocomelia. Drawing of a hand with one more thumb or finger than usual. ... Polymelia is the birth defect of having five or more limbs. ... Dwarfism is typically a pathological condition in which the physical size of a person, animal, or plant is well below normal. ... Cleidocranial dysostosis or Cleidocranial dysplasia is a hereditary congenital abnormality of humans. ... Phocomelia (from Greek seal-limbs) is a congenital disorder that presents at birth as very short or absent long bones and flipper-like appearance of hands and feet that can occur as congenital abnormalities. ...

Occurrence rate

About 2% to 3% of babies are born with significant congenital birth defects. 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. Birth defects of the heart are the most common birth defect leading to death in infancy, accounting for 28% of infant deaths due to birth defects, while chromosomal abnormalities and respiratory abnormalities each account for 15%, and brain defects about 12%. In animals, the brain, or encephalon (Greek for in the head), is the control center of the central nervous system. ... The heart and lungs, from an older edition of Grays Anatomy. ... Human kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ... A limb (from the Old English lim) is a jointed appendage of the human or animal body; a large or main branch of a tree; a representative, branch or member of a group or organization. ... Figure 1: Chromosome. ...

Causes

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. Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Figure 1: Chromosome. ... Heredity (the adjective is hereditary) is the transfer of characteristics from parent to offspring, either through their genes or through the social institution called inheritance (for example, a title of nobility is passed from individual to individual according to relevant customs and/or laws). ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... In biology, mutations are changes to the genetic material (either DNA or RNA). ... A germ cell is a kind of cell that is part of the germline, and is involved in the reproduction of organisms. ...

Influences of the intrauterine environment of the fetus that 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, alcohol or 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. Teratogenesis is a medical term from the Greek, literally meaning monster-making, which derives from teratology, the study of the frequency, causation, and development of congenital malformations—misleadingly called birth defects. ... Folic acid and folate (the anion form) are forms of a water-soluble B vitamin. ... Bottles of cachaça, a Brazilian alcoholic beverage. ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery white Atomic mass 200. ... Phenytoin sodium (marketed as Dilantin® in the USA and as Epanutin® in the UK, by Parke-Davis, now part of Pfizer) is a commonly used antiepileptic. ... Rubella (also known as epidemic roseola, German measles, liberty measles[1] or three-day measles) is a disease caused by the Rubella virus. ... Syphilis is a sexually transmitted infection (STI) caused by a spirochaete bacterium, Treponema pallidum. ...

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 that implies an unknown cause, random occurrence, and a low recurrence risk for future children.

Risks throughout gestation

The greatest risk of a malformation occurring is between the third and eighth week of gestation. Before this time, any damage to the embryo is likely to result in fatality, and the baby will not be born. After eight weeks, the fetus and its organs are more developed and less sensitive to teratogenic incidents. Gestation is the carrying of an embryo or fetus inside a female viviparous animal. ... This article or section is in need of attention from an expert on the subject. ... Teratogenesis is a medical term from the Greek, literally meaning monster making. ...

The type of birth defect is also related to the time of exposure to a teratogen. For instance the heart is susceptible from three to eight weeks, but the ear is susceptible from a slightly later time to about twelve weeks. The heart and lungs, from an older edition of Grays Anatomy. ... Bat ears come in different sizes and shapes The ear is the sense organ that detects sound. ...

Infection in the mother early in the third week may damage the heart. An infection in the eleventh week is less likely to damage the heart, but the baby may be born deaf. The word deaf can have very different meanings depending on the background of the person speaking or the context in which the word is used. ...

References

• CDC’s National Center on Birth Defects and Developmental Disabilities
• The National Library of Medicine or MEDLINE/PubMed MeSH (medical subject heading) term
• Birth Defects Are Preventable

See also

• List of congenital disorders
• Fetal intervention
• ICD-10 Chapter Q: Congenital malformations, deformations and chromosomal abnormalities
• List of ICD-9 codes 740-759: Congenital anomalies