Congenital heart defects include patent ductus arteriosus, atrial septal defect, ventricular septal defect, and tetralogy of Fallot. Congenital anomalies of the nervous system include neural tube defects such as spina bifida, encephalocele, and anencephaly. Other congenital anomalies of the nervous system include the Arnold–Chiari malformation, the Dandy–Walker malformation, hydrocephalus, microencephaly, megalencephaly, lissencephaly, polymicrogyria, holoprosencephaly, and agenesis of the corpus callosum. Congenital anomalies of the gastrointestinal system include numerous forms of stenosis and atresia, and perforation, such as gastroschisis. Congenital anomalies of the kidney and urinary tract include renal parenchyma, kidneys, and urinary collecting system.Defects can be bilateral or unilateral, and different defects often coexist in an individual child. Primarily metabolic
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. Other
Other well-defined genetic conditions may affect the production of hormones, receptors, structural proteins, and ion channels. Causes
Alcohol exposure
The mothers consumption of alcohol during pregnancy can cause a continuum of various permanent birth defects: craniofacial abnormalities, brain damage, intellectual disability, heart disease, kidney abnormality, skeletal anomalies, ocular abnormalities.The prevalence of children affected is estimated at least 1% in U.S. as well in Canada. Very few studies have investigated the links between paternal alcohol use and offspring health.However, recent animal research has shown a correlation between paternal alcohol exposure and decreased offspring birth weight.
An example of a birth defect is cleft palate, which occurs during the fourth through seventh weeks of gestation. Body tissue and special cells from each side of the head grow toward the center of the face. They join to make the face. A cleft means a split or separation; the "roof" of the mouth is called the palate. A congenital malformation is a physical anomaly that is deleterious, i.e. a structural defect perceived as a problem. A typical combination of malformations affecting more than one body part is referred to as a malformation syndrome. Some conditions are due to abnormal tissue development:
A malformation is associated with a disorder of tissue development. Malformations often occur in the first trimester. A dysplasia is a disorder at the organ level that is due to problems with tissue development. Conditions also can arise after tissue is formed:
A deformation is a condition arising from mechanical stress to normal tissue. Deformations often occur in the second or third trimester, and can be due to oligohydramnios. A disruption involves breakdown of normal tissues. When multiple effects occur in a specified order, they are known as a sequence. When the order is not known, it is a syndrome. Examples of primarily structural congenital disorders
A limb anomaly is called a dysmelia. These include all forms of limbs anomalies, such as amelia, ectrodactyly, phocomelia, polymelia, polydactyly, syndactyly, polysyndactyly, oligodactyly, brachydactyly, achondroplasia, congenital aplasia or hypoplasia, amniotic band syndrome, and cleidocranial dysostosis.