Teratology is the study of abnormalities of physiological development. It is often thought of as the study of human congenital abnormalities, but it is broader than that, taking into account other non-birth developmental stages, including puberty; and other organisms, including plants. The related term developmental toxicity includes all manifestations of abnormal development that are caused by environmental insult. These may include growth retardation, delayed mental development or other congenital disorders without any structural malformations.
A birth defect, also known as a congenital disorder, is a condition present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth defects are divided into two main types: structural disorders in which problems are seen with the shape of a body part and functional disorders in which problems exist with how a body part works. Functional disorders include metabolic and degenerative disorders. Some birth defects include both structural and functional disorders.
Patau syndrome is a syndrome caused by a chromosomal abnormality, in which some or all of the cells of the body contain extra genetic material from chromosome 13. The extra genetic material disrupts normal development, causing multiple and complex organ defects.
Edwards syndrome, also known as trisomy 18, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18. Many parts of the body are affected. Babies are often born small and have heart defects. Other features include a small head, small jaw, clenched fists with overlapping fingers, and severe intellectual disability.
Prenatal testing consists of prenatal screening and prenatal diagnosis, which are aspects of prenatal care that focus on detecting problems with the pregnancy as early as possible. These may be anatomic and physiologic problems with the health of the zygote, embryo, or fetus, either before gestation even starts or as early in gestation as practicable. Screening can detect problems such as neural tube defects, chromosome abnormalities, and gene mutations that would lead to genetic disorders and birth defects, such as spina bifida, cleft palate, Downs Syndrome, Tay–Sachs disease, sickle cell anemia, thalassemia, cystic fibrosis, muscular dystrophy, and fragile X syndrome. Some tests are designed to discover problems which primarily affect the health of the mother, such as PAPP-A to detect pre-eclampsia or glucose tolerance tests to diagnose gestational diabetes. Screening can also detect anatomical defects such as hydrocephalus, anencephaly, heart defects, and amniotic band syndrome.
Arthrogryposis, describes congenital joint contracture in two or more areas of the body. It derives its name from Greek, literally meaning "curving of joints".
Fetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person whose mother drank alcohol during pregnancy. Symptoms can include an abnormal appearance, short height, low body weight, small head size, poor coordination, low intelligence, behavior problems, learning difficulties and problems with hearing or sight. Those affected are more likely to have trouble in school, legal problems, participate in high-risk activities and have problems with alcohol or other drugs. The most severe form of the condition is known as fetal alcohol syndrome (FAS). Other types include partial fetal alcohol syndrome (pFAS), alcohol-related neurodevelopmental disorder (ARND) and alcohol-related birth defects (ARBD). Some accept only FAS as a diagnosis, seeing the evidence as inconclusive with respect to other types.
Primrose syndrome is a rare, slowly progressive genetic disorder that can vary symptomatically between individual cases, but is generally characterised by ossification of the external ears, learning difficulties, and facial abnormalities. It was first described in 1982 in Scotland's Royal National Larbert Institution by Dr D.A.A. Primrose.
Prenatal development includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal development until birth.
Complications of pregnancy are health problems that are related to pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. Severe complications of pregnancy, childbirth, and the puerperium are present in 1.6% of mothers in the US, and in 1.5% of mothers in Canada. In the immediate postpartum period (puerperium), 87% to 94% of women report at least one health problem. Long-term health problems are reported by 31% of women.
Trimethadione is an oxazolidinedione anticonvulsant. It is most commonly used to treat epileptic conditions that are resistant to other treatments.
Fetal warfarin syndrome is a disorder of the embryo which occurs in a child whose mother took the medication warfarin during pregnancy. Resulting abnormalities include low birth weight, slower growth, mental retardation, deafness, small head size, and malformed bones, cartilage, and joints.
Robinow syndrome is an extremely rare genetic disorder characterized by short-limbed dwarfism, abnormalities in the head, face, and external genitalia, as well as vertebral segmentation. The disorder was first described in 1969 by human geneticist Meinhard Robinow, along with physicians Frederic N. Silverman and Hugo D. Smith, in the American Journal of Diseases of Children. By 2002, over 100 cases had been documented and introduced into medical literature.
Aarskog–Scott syndrome is a rare disease inherited as X-linked and characterized by short stature, facial abnormalities, skeletal and genital anomalies. This condition mainly affects males, although females may have mild features of the syndrome.
The genetics and abortion issue is an extension of the abortion debate and the disability rights movement. Since the advent of forms of prenatal diagnosis, such as amniocentesis and ultrasound, it has become possible to detect the presence of congenital disorders in the fetus before birth. Specifically, disability-selective abortion is the abortion of fetuses that are found to have non-fatal mental or physical defects detected through prenatal testing. Many prenatal tests are now considered routine, such as testing for Down syndrome. Women who are discovered to be carrying fetuses with disabilities are often faced with the decision of whether to abort or to prepare to parent a child with disabilities.
Dubowitz syndrome is a rare genetic disorder characterized by microcephaly, stunted growth, and a receding chin. Symptoms vary among patients, but other characteristics include a soft, high-pitched voice, partial webbing of the fingers and toes, palate deformations, genital abnormalities, language difficulties, and an aversion to crowds. The pathogenesis of the disease is yet to be identified, and no medical tests can definitively diagnose the disease. The primary method of diagnosis is to identify facial phenotypes. Since it was first described in 1965 by English physician Victor Dubowitz, over 140 cases have been reported worldwide. Although the majority of cases have been reported from the United States, Germany, and Russia, the disorder appears to affect both genders and all ethnicities equally.
Acrocallosal syndrome is a rare autosomal recessive syndrome characterized by corpus callosum agenesis, polydactyly, multiple dysmorphic features, motor and intellectual disabilities, and other symptoms. The syndrome was first described by Albert Schinzel in 1979.
Hydrolethalus syndrome (HLS) is a rare genetic disorder that causes improper fetal development, resulting in birth defects and, most commonly, stillbirth.
Developmental toxicity is any structural or functional alteration, reversible or irreversible, which interferes with homeostasis, normal growth, differentiation, development or behavior, and which is caused by environmental insult. It is the study of adverse effects on the development of the organism resulting from exposure to toxic agents before conception, during prenatal development, or post-natally until puberty. The substance that causes developmental toxicity from embryonic stage to birth is called teratogens. The effect of the developmental toxicants depends on the type of substance, dose and duration and time of exposure.
Alcohol use in pregnancy includes use of alcohol during gestation, including the time before the woman is aware of the pregnancy. No amount of alcohol is considered safe to drink while pregnant and there is no safe time point or trimester in pregnancy to drink alcohol. Fetal alcohol spectrum disorders (FASDs) are a group of conditions that can occur in a person whose mother drank alcohol during pregnancy. The most severe form of the condition is known as fetal alcohol syndrome (FAS). Problems may include an abnormal appearance, short height, low body weight, small head size, poor coordination, low intelligence, behavioral problems, hearing loss, and vision problems. Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and have trouble with alcohol and recreational drug use. Alcohol use during pregnancy also can cause spontaneous abortion, stillbirth, low birthweight, and prematurity. Not all infants exposed to alcohol in utero will have defects related to the alcohol consumption. The use of alcohol during pregnancy is associated with domestic violence and potential harm to the infant.
