User:CarmenBraud/Spina bifida

Lead
Spina bifida is believed to be due to a combination of genetic and environmental factors. After having one child with the condition, or if one of the parents has the condition, there is a 4% chance that the next child will also be affected. Not having enough folate (vitamin B9) in the diet before and during pregnancy also plays a significant role. Other risk factors include certain antiseizure medications, obesity and poorly controlled diabetes. Diagnosis may occur either before or after a child is born. Before birth, if a blood test or amniocentesis finds a high level of alpha-fetoprotein (AFP), there is a higher risk of spina bifida. Ultrasound examination may also detect the problem. Medical imaging can confirm the diagnosis after birth. Spina bifida is a type of neural tube defect related to but distinct from other types such as anencephaly and encephalocele.

Cause
Spina bifida is believed to be caused by a combination of genetic and environmental factors. The genetic component is estimated at 60–70%, but few causative genes have been identified, despite much information gathered from mouse models. After having one child with the condition, or if a parent has the condition, there is a 4% chance the next child will also be affected. A folic acid deficiency during pregnancy also plays a significant role. Other risk factors include certain antiseizure medications, obesity, and poorly managed diabetes. Alcohol misuse can trigger macrocytosis which discards folate. After stopping the drinking of alcohol, a time period of months is needed to rejuvenate bone marrow and recover from the macrocytosis.

Those who are white or Hispanic have a higher risk. Girls are more prone to being born with spina bifida.

Prevention
There is neither a single cause of spina bifida nor any known way to prevent it entirely. However, dietary supplementation with folic acid has been shown to be helpful in reducing the incidence of spina bifida. Sources of folic acid include whole grains, fortified breakfast cereals, dried beans, leaf vegetables and fruits. However it is difficult for women to get the recommended 400 micrograms of folic acid a day from unfortified foods. Globally, fortified wheat flour is credited with preventing 50 thousand neural tube birth defects like spina bifida a year, but 230 thousand could be prevented every year through this strategy.

In the year 2020, expert analysis showing that 61,680 spina bifida aperta cases were prevented via mandatory folic acid fortification of cereal grains in 58 countries, which translates to 22% prevention of total possible spina bifida aperta cases globally. However, despite the research and results, many countries in Africa, Asia, and Europe have yet to implement fortification.

Folate fortification of enriched grain products has been mandatory in the United States since 1998. This prevents an estimated 600 to 700 incidents of spina bifida a year in the U.S. and saves $400 - $600 million in healthcare expenses. The U.S. Food and Drug Administration, Public Health Agency of Canada and the UK Department of Health and Social Care (DHSC) recommended amount of folic acid for women of childbearing age and women planning to become pregnant is at least 0.4 mg/day of folic acid from at least three months before conception, and continued for the first 12 weeks of pregnancy. Women who have already had a baby with spina bifida or other type of neural tube defect, or are taking anticonvulsant medication, should take a higher dose of 4–5 mg/day.

Certain mutations in the gene VANGL1 have been linked with spina bifida in some families with a history of the condition.

Screening
It is important to keep in mind that tests are not 100% perfect, so even though screening results present negative, there is still a slight chance that spina bifida is present.

Open spina bifida can usually be detected during pregnancy by fetal ultrasound. Increased levels of maternal serum alpha-fetoprotein (MSAFP) should be followed up by two tests – an ultrasound of the fetal spine and amniocentesis of the mother's amniotic fluid (to test for alpha-fetoprotein and acetylcholinesterase). AFP tests are now mandated by some state laws (including California) and failure to provide them can have legal ramifications. In one case, a man born with spina bifida was awarded a $2-million settlement after court found his mother's OBGYN negligent for not performing these tests.

It is important to note that this is not without risk, which occurs approximately every 1 in 900 tests, and include leaking amniotic fluid, though this generally has no effect on pregnancy. However, second-trimester amniocentesis carries a slight risk of miscarriage of 0.1% to 0.3% when done by a skilled person using ultrasound, though research suggests that the risk of miscarriage is higher for amniocentesis done before 15 weeks of pregnancy. Infection transmission may occur from mother to child if the mother has infections such as hepatitis C, toxoplasmosis, or HIV/AIDS, or Rh sensitization, which ultimately damages the baby's red blood cells. Needle injury to the baby may occur, though serious injury is very rare, along with triggering a uterine infection, which is also very rare

Spina bifida may be associated with other malformations as in dysmorphic syndromes, often resulting in spontaneous miscarriage. In the majority of cases, though, spina bifida is an isolated malformation.

Genetic counseling and further genetic testing, such as amniocentesis, may be offered during the pregnancy, as some neural tube defects are associated with genetic disorders such as trisomy 18. Ultrasound screening for spina bifida is partly responsible for the decline in new cases, because many pregnancies are terminated out of fear that a newborn might have a poor future quality of life. With modern medical care, the quality of life of patients has greatly improved.

Treatment
There is no known cure for the nerve damage caused by spina bifida. Standard treatment is surgery after delivery. This surgery aims to prevent further damage of the nervous tissue and to prevent infection; pediatric neurosurgeons operate to close the opening on the back. The spinal cord and its nerve roots are put back inside the spine and covered with meninges. In addition, a shunt may be surgically installed to provide a continuous drain for the excess cerebrospinal fluid produced in the brain, as happens with hydrocephalus. Shunts most commonly drain into the abdomen or chest wall.[citation needed]

Epidemiology
Rates of other types of spina bifida vary significantly by country from 0.1 to 5 per 1000 births. On average in developed countries it occurs in about 0.4 per 1000 births. In the United States it affected about 0.7 per 1000 births, and in India about 1.9 per 1000 births. Part of this difference is believed to be due to race, with Caucasians at higher risk, and part due to environmental factors. It is most common in the Celtic people (12.5 per 10,000 live births), and it is rare in Asians and people of African descent.

In the United States, rates are higher on the East Coast than on the West Coast, and higher in white people (one case per 1000 live births) than in black people (0.1–0.4 case per 1000 live births). Immigrants from Ireland have a higher incidence of spina bifida than do natives. Highest rates of the defect in the USA can be found in Hispanic youth.

The highest incidence rates worldwide were found in Ireland and Wales, where three to four cases of myelomeningocele per 1000 population have been reported during the 1970s, along with more than six cases of anencephaly (both live births and stillbirths) per 1000 population. The reported overall incidence of myelomeningocele in the British Isles was 2.0–3.5 cases per 1000 births. Since then, the rate has fallen dramatically with 0.15 per 1000 live births reported in 1998, though this decline is partially accounted for because some fetuses are aborted when tests show signs of spina bifida (see Pregnancy screening above).