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Probably, the most well-known teratogenic drug is thalidomide. It was developed near the end of the 1950s by Chemie Grűnenthal as a sleep inducing aid and antiemetic. Because of its ability to prevent nausea it was prescribed for pregnant women in almost 50 countries worldwide between 1956–1962. Until William McBride published the study leading to its withdrawal from the market at 1961, about 8- 10 000 severely malformed children were born. The most typical disorder induced by thalidomide were reductional deformities of the long bones of the extremities. Phocomelia otherwise a rare deformity, which therefore helped to recognise the teratogenic effect of the new drug. Among other malformations caused by thalidomide were those of ears, eyes, brain, kidney, heart, digestive and respiratory tract. 40% of the prenatally affected children died soon after birth. As thalidomide is used today as a treatment for multiple myeloma and leprosy, several births of affected children were described in spite of the strictly required use of contraception among female patients treated by it.
Vitamin A, or retinol, is the sole vitamin which is embryotoxic even in a therapeutic dose, for example in multivitamins, because its metabolite, the retinoic acid, plays an important role as a signal molecule in the development of several tisues and organs. Its natural precursor, the β-carotene, is considered safe, whereas the consumption of animal liver can lead to malformation, as the liver stores lipophile vitamins, including retinol. Isotretinoin (13-cis-retinoic-acid; brand name Roaccutane), vitamine A analog, which is often used to treat severe acne, is such a strong teratogen that just a single dose taken by a pregnant woman (even transdermally) may result in serious birth defects. Because of this effect, most countries have systems in place to ensure that it is not given to pregnant women, and that the patient is aware of how important it is to prevent pregnancy during and at least one month after treatment. Medical guidelines also suggest that pregnant women should limit vitamin A intake to about 700 μg/day, as it has teratogenic potential when consumed in excess. Vitamine A and similar substances can induce spontaneous abortions, premature births, defects of eyes (microphthalmia), ears, thymus, face deformities, neurological (hydrocephalus, microcephalia) and cardiovascular defects, as well as mental retardation.
Tetracycline, an antibiotic, should never be prescribed to women in the reproductive age or children, because of its negative impact on bone mineralization and teeth mineralization. The "tetracycline teeth" have brown or grey colour as a result of a defective development of both the dentine and the enamel of teeth.
Several anticonvulsants are known to be highly teratogenic. Phenytoin, also known as diphenylhydantoin, along with carbamazepine is responsible for the fetal hydantoin syndrome, which may typically include broad nose base, cleft lip and/or palate, microcephalia, nails and fingers hypoplasia, intrauterine growth restriction and mental retardation. Trimethadione taken during pregnancy is responsible for the fetal trimethadione syndrome, characterized by craniofacial, cardiovascular, renal and spine malformations, along with a delay in mental and physical development. Valproate has anti-folate effects, leading to neural tube closure-related defects such as spina bifida. Lower IQ and autism have recently also been reported as a result of intrauterine valproate exposure.
Hormonal contraception is considered as harmless for the embryo. Peterka and Novotná do however state that syntethic progestines used to prevent miscarriage in the past frequently caused masculinization of the outer reproductive organs of female newborns due to their androgenic activity. Diethylstilbestrol is a synthetic estrogen used from the 1940s to 1971 when the prenatal exposition has been linked to the clear-cell adenocarcinoma of the vagina. Following studies showed elevated risks for other tumors and congenital malformations of the sex organs for both sexes.
All cytostatics are strong teratogens, abortion is usually recommended when pregnancy is found during or before chemotherapy. Aminopterin, a cytostatic drug with anti-folate effect, was used during the 1950s and 1960s to induce therapeutic abortions. In some cases the abortion didn´t happen, but the newborns suffered a fetal aminopterin syndrome consisting of growth retardation, craniosynostosis, hydrocephalus, facial dismorphities, mental retardation and/or leg defomities
PHACE syndrome needs to be managed by a multidisciplinary team of experts. Additional specialties such as cardiology, ophthalmology, neurology, and neurosurgery may need to be involved. The team of experts pay close attention to how these children develop throughout the school age period.
PHACE Syndrome Handbook - Dr. Beth Drolet
In 2013, the PHACE Syndrome Community was formed. The non-profit entity was developed to raise awareness about the condition, support patients and families of those with the condition and raise money for research into causes and treatment.
Management of AOS is largely symptomatic and aimed at treating the various congenital anomalies present in the individual. When the scalp and/or cranial bone defects are severe, early surgical intervention with grafting is indicated.
While Larsen syndrome can be lethal if untreated, the prognosis is relatively good if individuals are treated with orthopedic surgery, physical therapy, and other procedures used to treat the symptoms linked with Larsen syndrome.
For the survivors of the atomic bombing of Hiroshima and Nagasaki, who are known as the "Hibakusha", no statistically demonstrable increase of birth defects/congenital malformations was found among their later conceived children, or found in the later conceived children of cancer survivors who had previously received radiotherapy.
The surviving women of Hiroshima and Nagasaki who were able to conceive, though exposed to substantial amounts of radiation, later had children with no higher incidence of abnormalities/birth defects than in the Japanese population as a whole.
Relatively few studies have researched the effects of paternal radiation exposure on offspring. Following the Chernobyl disaster, it was assumed in the 1990s that the germ line of irradiated fathers suffered minisatellite mutations in the DNA, which was inherited by descendants. more recently however, the World Health Organization states, "children conceived before or after their father's exposure showed no statistically significant differences in mutation frequencies". This statistically insignificant increase was also seen by independent researchers analyzing the children of the liquidators. Animal studies have shown that incomparably "massive" doses of X-ray irradiation of male mice resulted in birth defects of the offspring.
In the 1980s, a relatively high prevalence of pediatric leukemia cases in children living near a nuclear processing plant in West Cumbria, UK, led researchers to investigate whether the cancer was a result of paternal radiation exposure. A significant association between paternal irradiation and offspring cancer was found, but further research areas close to other nuclear processing plants did not produce the same results. Later this was determined to be the Seascale cluster in which the leading hypothesis is the influx of foreign workers, who have a different rate of leukemia within their race than the British average, resulted in the observed cluster of 6 children more than expected around Cumbria.
Usually the hemangioma requires medical therapy. The child may need other therapies, depending on what other organs or structures are involved.
No cure or treatment option for individuals with Hydrolethalus syndrome currently exist.
Treatment for Larsen syndrome varies according to the symptoms of the individual. Orthopedic surgery can be performed to correct the serious joint defects associated with Larsen syndrome. Reconstructive surgery can be used to treat the facial abnormalities. Cervical kyphosis can be very dangerous to an individual because it can cause the vertebrae to disturb the spinal cord. Posterior cervical arthrodesis has been performed on patients with cervical kyphosis, and the results have been successful Propranolol has been used to treat some of the cardiac defects associated with Marfan's syndrome, so the drug also has been suggested to treat cardiac defects associated with Larsen syndrome.
Patients with abnormal cardiac and kidney function may be more at risk for hemolytic uremic syndrome
The overall prognosis is excellent in most cases. Most children with Adams–Oliver syndrome can likely expect to have a normal life span. However, individuals with more severe scalp and cranial defects may experience complications such as hemorrhage and meningitis, leading to long-term disability.
No treatment is available for most of these disorders. Mannose supplementation relieves the symptoms in PMI-CDG (CDG-Ib) for the most part, even though the hepatic fibrosis may persist. Fucose supplementation has had a partial effect on some SLC35C1-CDG (CDG-IIc or LAD-II) patients.
The incidence of VACTERL association is estimated to be approximately 1 in 10,000 to 1 in 40,000 live-born infants. It is seen more frequently in infants born to diabetic mothers. While most cases are sporadic, there are clearly families who present with multiple involved members.
Treatment with isotretinoin may induce substantial resolution of skin lesions, but the risk of secondary infection remains.
The outcome of this disease is dependent on the severity of the cardiac defects. Approximately 1 in 3 children with this diagnosis require shunting for the hydrocephaly that is often a consequence. Some children require extra assistance or therapy for delayed psychomotor and speech development, including hypotonia.
3C syndrome is very rare, occurring in less than 1 birth per million. Because of consanguinity due to a founder effect, it is much more common in a remote First Nations village in Manitoba, where 1 in 9 people carries the recessive gene.
Zunich–Kaye syndrome, also known as Zunich neuroectodermal syndrome, is a rare congenital ichthyosis first described in 1983. It is also referred to as CHIME syndrome, after its main symptoms (colobomas, heart defects, ichthyosiform dermatosis, intellectual disability, and either ear defects or epilepsy). It is a congenital syndrome with only a few cases studied and published.
Hydrolethalus syndrome (less commonly referred to as Salonen-Herva-Norio syndrome) is a rare genetic disorder that causes improper fetal development, resulting in birth defects and often stillbirth.
It is associated with HYLS1 mutations.
Oculofaciocardiodental syndrome is a rare X linked genetic disorder.
In 1996, the United States Food and Drug Administration published regulations requiring the addition of folic acid to enriched breads, cereals, flour and other grain products. It is important to note that during the first four weeks of pregnancy (when most women do not even realize that they are pregnant), adequate folate intake is essential for proper operation of the neurulation process. Therefore, women who could become pregnant are advised to eat foods fortified with folic acid or take supplements in addition to eating folate-rich foods to reduce the risks of serious birth defects.
In Canada, mandatory fortification of selected foods with folic acid has been shown to reduce the incidence of neural tube defects by 46%.
Women who may become pregnant are advised to get 400 micrograms of folic acid daily. Women who have previously given birth to a child with a neural tube defect may benefit from a supplement containing 4.0 mg/5.0 mg in the UK mg daily, following advice provided by their doctor.
Fetal hydantoin syndrome, also called fetal dilantin syndrome is a group of defects caused to the developing fetus by exposure to teratogenic effects of phenytoin or carbamazepine. Dilantin is the brand name of the drug phenytoin sodium in the United States, commonly used in the treatment of epilepsy.
It may also be called congenital hydantoin syndrome, Fetal Hydantoin Syndrome, Dilantin Embryopathy, or Phenytoin Embryopathy.
Association with EPHX1 has been suggested.
A congenital disorder of glycosylation (previously called carbohydrate-deficient glycoprotein syndrome) is one of several rare inborn errors of metabolism in which glycosylation of a variety of tissue proteins and/or lipids is deficient or defective. Congenital disorders of glycosylation are sometimes known as CDG syndromes. They often cause serious, sometimes fatal, malfunction of several different organ systems (especially the nervous system, muscles, and intestines) in affected infants. The most common subtype is CDG-Ia (also referred to as PMM2-CDG) where the genetic defect leads to the loss of phosphomannomutase 2, the enzyme responsible for the conversion of mannose-6-phosphate into mannose-1-phosphate.
About one third of children whose mothers are taking this drug during pregnancy typically have intrauterine growth restriction with a small head and develop minor dysmorphic craniofacial features and limb defects including hypoplastic nails and distal phalanges (birth defects). A smaller population will have growth problems and developmental delay, or intellectual disability. Methemoglobinemia is a rarely seen side effect.
Heart defects and cleft lip may also be featured.
This condition is caused by lesions in the BCOR gene located on the short arm of the X chromosome (Xp11.4). This protein encodes the BCL6 corepressor but little is currently known about its function. The inheritance is X-linked dominant.
A genetically related disorder is Lenz microphthalmia syndrome.
Known environmental factors include certain infections during pregnancy such as Rubella, drugs (alcohol, hydantoin, lithium and thalidomide) and maternal illness (diabetes mellitus, phenylketonuria, and systemic lupus erythematosus).
Being overweight or obese increases the risk of congenital heart disease. Additionally, as maternal obesity increases, the risk of heart defects also increases. A distinct physiological mechanism has not been identified to explain the link between maternal obesity and CHD, but both prepregnancy folate deficiency and diabetes have been implicated in some studies.
Treatments of NTDs depends on the severity of the complication. No treatment is available for anencephaly and infants usually do not survive more than a few hours. Aggressive surgical management has improved survival and the functions of infants with spina bifida, meningoceles and mild myelomeningoceles. The success of surgery often depends on the amount of brain tissue involved in the encephalocele. The goal of treatment for NTDs is to allow the individual to achieve the highest level of function and independence. Fetal surgery in utero before 26 weeks gestation has been performed with some hope that there is benefit to the final outcome including a reduction in Arnold–Chiari malformation and thereby decreases the need for a ventriculoperitoneal shunt but the procedure is very high risk for both mother and baby and is considered extremely invasive with questions that the positive outcomes may be due to ascertainment bias and not true benefit. Further, this surgery is not a cure for all problems associated with a neural tube defect. Other areas of research include tissue engineering and stem cell therapy but this research has not been used in humans.