A deficiency of folate itself does not cause neural tube defects. The association seen between reduced neural tube defects and folic acid supplementation is due to a gene-environment interaction such as vulnerability caused by the C677T Methylenetetrahydrofolate reductase (MTHFR) variant. Supplementing folic acid during pregnancy reduces the prevalence of NTDs by not exposing this otherwise sub-clinical mutation to aggravating conditions. Other potential causes can include folate antimetabolites (such as methotrexate), mycotoxins in contaminated corn meal, arsenic, hyperthermia in early development, and radiation. Maternal obesity has also been found to be a risk factor for NTDs. Studies have shown that both maternal cigarette smoking and maternal exposure to secondhand smoke increased the risk for neural tube defects in offspring. A mechanism by which maternal exposure to cigarette smoke could increase NTD risk in offspring is suggested by several studies that show an association between cigarette smoking and elevations of homocysteine levels. Cigarette smoke during pregnancy, including secondhand exposure, can increase the risk of neural tube defects. All of the above may act by interference with some aspect of normal folic acid metabolism and folate linked methylation related cellular processes as there are multiple genes of this type associated with neural tube defects.

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.

Folate fortification of enriched grain products has been mandatory in the United States since 1998. The U.S. Food and Drug Administration, Public Health Agency of Canada and UK 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.

Folic acid supplementation reduces the prevalence of neural tube defects by approximately 70% of neural tube defects indicating that 30% are not folate-dependent and are due to some cause other than alterations of methylation patterns. Multiple other genes related to neural tube defects exist which are candidates for folate insensitive neural tube defects. There are also several syndromes such as Meckel syndrome, and Triploid Syndrome which are frequently accompanied by neural tube defects that are assumed to be unrelated to folate metabolism

Spina bifida is sometimes caused by the failure of the neural tube to close during the first month of embryonic development (often before the mother knows she is pregnant). Some forms are known to occur with primary conditions that cause raised central nervous system pressure, raising the possibility of a dual pathogenesis.

In normal circumstances, the closure of the neural tube occurs around the 23rd (rostral closure) and 27th (caudal closure) day after fertilization. However, if something interferes and the tube fails to close properly, a neural tube defect will occur. Medications such as some anticonvulsants, diabetes, obesity, and having a relative with spina bifida can all affect the probability of neural tube malformation.

Extensive evidence from mouse strains with spina bifida indicates that there is sometimes a genetic basis for the condition. Human spina bifida, like other human diseases, such as cancer, hypertension and atherosclerosis (coronary artery disease), likely results from the interaction of multiple genes and environmental factors.

Research has shown the lack of folic acid (folate) is a contributing factor in the pathogenesis of neural tube defects, including spina bifida. Supplementation of the mother's diet with folate can reduce the incidence of neural tube defects by about 70%, and can also decrease the severity of these defects when they occur. It is unknown how or why folic acid has this effect.

Spina bifida does not follow direct patterns of heredity as do muscular dystrophy or haemophilia. Studies show a woman having had one child with a neural tube defect such as spina bifida has about a 3% risk of having another affected child. This risk can be reduced with folic acid supplementation before pregnancy. For the general population, low-dose folic acid supplements are advised (0.4 mg/day).

Substances whose toxicity can cause congenital disorders are called "teratogens", and include certain pharmaceutical and recreational drugs in pregnancy as well as many environmental toxins in pregnancy.

A review published in 2010 identified 6 main teratogenic mechanisms associated with medication use: folate antagonism, neural crest cell disruption, endocrine disruption, oxidative stress, vascular disruption and specific receptor- or enzyme-mediated teratogenesis.

It is estimated that 10% of all birth defects are caused by prenatal exposure to a teratogenic agent. These exposures include, but are not limited to, medication or drug exposures, maternal infections and diseases, and environmental and occupational exposures. Paternal smoking use has also been linked to an increased risk of birth defects and childhood cancer for the offspring, where the paternal germline undergoes oxidative damage due to cigarette use. Teratogen-caused birth defects are potentially preventable. Studies have shown that nearly 50% of pregnant women have been exposed to at least one medication during gestation. During pregnancy, a female can also be exposed to teratogens from the contaminated clothing or toxins within the seminal fluid of a partner. An additional study found that of 200 individuals referred for genetic counseling for a teratogenic exposure, 52% were exposed to more than one potential teratogen.

A low socioeconomic status in a deprived neighborhood may include exposure to “environmental stressors and risk factors.” Socioeconomic inequalities are commonly measured by the Cartairs-Morris score, Index of Multiple Deprivation, Townsend deprivation index, and the Jarman score. The Jarman score, for example, considers “unemployment, overcrowding, single parents, under-fives, elderly living alone, ethnicity, low social class and residential mobility.” In Vos’ meta-analysis these indices are used to view the effect of low SES neighborhoods on maternal health. In the meta-analysis, data from individual studies were collected from 1985 up until 2008. Vos concludes that a correlation exists between prenatal adversities and deprived neighborhoods. Other studies have shown that low SES is closely associated with the development of the fetus in utero and growth retardation. Studies also suggest that children born in low SES families are “likely to be born prematurely, at low birth weight, or with asphyxia, a birth defect, a disability, fetal alcohol syndrome, or AIDS.” Bradley and Corwyn also suggest that congenital disorders arise from the mother’s lack of nutrition, a poor lifestyle, maternal substance abuse and “living in a neighborhood that contains hazards affecting fetal development (toxic waste dumps).” In a meta-analysis that viewed how inequalities influenced maternal health, it was suggested that deprived neighborhoods often promoted behaviors such as smoking, drug and alcohol use. After controlling for socioeconomic factors and ethnicity, several individual studies demonstrated an association with outcomes such as perinatal mortality and preterm birth.

Tethered spinal cord can be caused by various conditions but the main cause is when tissue attachments limit the movement of the spinal cord in the spinal column which causes abnormal stretching of the cord. The tethered spinal cord syndrome is correlated with having the causes:

- Spina bifida

- Occulta

- Mylomeningocele

- Meningocele

- History of spinal trauma

- History of spinal surgery

- Tumor(s) in the spinal column

- Thickened and/or tight filum terminale

- Lipoma(s) in the spinal column

- Dermal Sinus Tract (congenital deformity)

- Diastematomyelia (split spinal cord)

Tethered spinal cord is a disorder and not a mechanism so it does not spread to other people and there are no measures that can be done to prevent it beforehand. The only preventative measure that is successful is to surgically untether the spinal cord though there might already be irreversible damage.

In tethered spinal cord cases Spina bifida can be accompanied by tethering of the spinal cord but in rare cases with Spina bifida Occulta. Tethering of the spinal cord tends to occur in the cases of Spina bifida with mylomeningocele. In a normal person the spine grows faster than the spinal cord during development which causes the end of the spinal cord to appear to rise relative to the bony spine next to it. By the time of birth the spinal cord is located between L1 and L2. In a baby with Spina bifida the spinal cord is still attached to the skin around it preventing it from rising properly. This occurs because the spinal cord in a child with Spina bifida is low lying and tethered at the bottom. At the time of birth the mylomeningocele is separated from the skin but the spinal cord is still stuck in the same place. As the child begins to grow the spinal cord remains in the same place becoming stretched out causing the tight cord and the tethering at the end. With this type of tethering there is an interference with the blood supply to the nerves and body which can then cause the deterioration of the body causing orthopedic, neurological, and urological problems. With milder forms of Spina bifida such as Occulta, may be related to the degree of strain on the cord which can become worse with physical activity, injury, pregnancy, bone spurs, or spinal stenosis. The tethered cord in this case might not be diagnosed until adulthood when it worsens and can still cause neurological, orthopedic, and urological dysfunctions.

Although the exact cause is unknown, encephaloceles are caused by failure of the neural tube to close completely during fetal development. Research has indicated that teratogens (substances known to cause birth defects), trypan blue (a stain used to color dead tissues or cells blue), and arsenic may damage the developing fetus and cause encephaloceles.

Proper levels of folic acid have been shown to help prevent such defects when taken before pregnancy, and early in pregnancy.

Encephaloceles occur rarely, at a rate of one per 5,000 live births worldwide. Encephaloceles of the back of the head are more common in Europe and North America, while encephaloceles on the front of the head more frequently occur in Southeast Asia, Africa, Malaysia, and Russia. Ethnic, genetic, and environmental factors, as well as parental age, can all affect the likelihood of encephaloceles. The condition can occur in families with a family history of spina bifida.

Because the shunt systems are too expensive for most people in developing countries, such people often die without getting a shunt. Worse, the rate of revision in shunt systems adds to the cost of shunting many times. Looking at this point, a study compares shunt systems and highlights the role of low-cost shunt systems in most of the developing countries. It compares the Chhabra shunt system to shunt systems from developed countries.

Meningohydroencephalocoele (AmE: meningohydroencephalocele) is a form of meningocele (AmE) - a developmental abnormality of the central nervous system.

Like meningocoele, meningohydroencephalocoele is caused by defects in bone ossification; in particular, the intramembranous ossification related to the closure of infantile fontanelles. It refers to the protrusion of the meninges between the un-fused bones, to lie subcutaneously.

- Meningocoele - refers to herniation of meninges.

- Meningoencephalocoele refers to the condition if brain tissue is included with the meninges in the herniation.

- Meningohydroencephalocoele refers to the condition including meninges, brain tissue and part of the ventricular system in the herniation.

Encephalocoele defects occur in approximately 1 in 2000 live births.

Non-communicating hydrocephalus, or obstructive hydrocephalus, is caused by a CSF-flow obstruction.

- Foramen of Monro obstruction may lead to dilation of one or, if large enough (e.g., in colloid cyst), both lateral ventricles.

- The aqueduct of Sylvius, normally narrow to begin with, may be obstructed by a number of genetically or acquired lesions (e.g., atresia, ependymitis, hemorrhage, tumor) and lead to dilation of both lateral ventricles as well as the third ventricle.

- Fourth ventricle obstruction will lead to dilatation of the aqueduct as well as the lateral and third ventricles (e.g., Chiari malformation).

- The foramina of Luschka and foramen of Magendie may be obstructed due to congenital malformation (e.g., Dandy-Walker malformation).

A pseudomeningocele is an abnormal collection of cerebrospinal fluid (CSF) that communicates with the CSF space around the brain or spinal cord. In contrast to a meningocele, in which the fluid is surrounded and confined by dura mater, in a pseudomeningocele, the fluid has no surrounding membrane, but is contained in a cavity within the soft tissues.

Pseudomeningocele may result after brain surgery, spine surgery, or brachial plexus avulsion injury.

Treatment for pseudomeningocele is conservative or may involve neurosurgical repair.

SCTs are very rare in adults, and as a rule these tumors are benign and have extremely low potential for malignancy. This estimation of potential is based on the idea that because the tumor existed for decades prior to diagnosis, without becoming malignant, it has little or no potential to ever become malignant. For this reason, and because coccygectomy in adults has greater risks than in babies, some surgeons prefer not to remove the coccyx of adult survivors of SCT. There are case reports of good outcomes.

Maternal complications of pregnancy may include mirror syndrome. Maternal complications of delivery may include a Cesarean section or, alternatively, a vaginal delivery with mechanical dystocia.

Complications of the mass effect of a teratoma in general are addressed on the teratoma page. Complications of the mass effect of a large SCT may include hip dysplasia, bowel obstruction, urinary obstruction, hydronephrosis and hydrops fetalis. Even a small SCT can produce complications of mass effect, if it is presacral (Altman Type IV). In the fetus, severe hydronephrosis may contribute to inadequate lung development. Also in the fetus and newborn, the anus may be imperforate.

Later complications of the mass effect and/or surgery may include neurogenic bladder, other forms of urinary incontinence, fecal incontinence, and other chronic problems resulting from accidental damage to or sacrifice of nerves and muscles within the pelvis. Removal of the coccyx may include additional complications. In one review of 25 patients, however, the most frequent complication was an unsatisfactory appearance of the surgical scar.

The Currarino syndrome (also Currarino triad) is an inherited congenital disorder where either the sacrum (the fused vertebrae forming the back of the pelvis) is not formed properly, or there is a mass in the presacral space in front of the sacrum, and (3) there are malformations of the anus or rectum. It can also cause an anterior meningocele or a presacral teratoma.

Presacral teratoma usually is considered to be a variant of sacrococcygeal teratoma. However, the presacral teratoma that is characteristic of the Currarino syndrome may be a distinct kind.

In dogs, perineal hernia usually is found on the right side. Most cases are in older intact (not neutered) male dogs (93 percent in one study). Breeds that may be at risk include Welsh Corgis, Boxers, Australian Kelpies, Boston Terriers, Collies, Dachshunds, Old English Sheepdogs, and Pekingese. Perineal hernias are rare in female dogs and uncommon in cats.

Dogs with benign prostatic hyperplasia have been found to have increased relaxin levels and suspected subsequent weakening of the pelvic diaphragm. In cats, perineal hernias are seen most commonly following perineal urethrostomy surgery or secondary to megacolon. Medical treatment consists of treatment of the underlying disease, enemas, and stool softeners. Because only about 20 percent of cases treated medically are free of symptoms, surgery is often necessary. Recurrence is common with or without surgery.

Several surgeries have been described for perineal hernias in dogs. The current standard involves transposition of the internal obturator muscle. This technique has a lower recurrence and complication rate than traditional hernia repair. A new technique uses porcine small intestinal submucosa as a biomaterial to help repair the defect. This is can also be done in combination with internal obturator muscle transposition, especially when that muscle is weak.

The disorder is an autosomal dominant genetic trait caused by a mutation in the HLXB9 homeobox gene. In 2000 the first large series of Currarino cases was genetically screened for HLXB9 mutations, and it was shown that the gene is specifically causative for the syndrome, but not for other forms of sacral agenesis. The study was published on the American Journal of Human Genetics.

In humans, a major cause of perineal hernia is perineal surgery without adequate reconstruction. In some cases, particularly surgeries to remove the coccyx and distal sacrum, adequate reconstruction is very difficult to achieve. The posterior perineum is a preferred point of access for surgery in the pelvic cavity, particularly in the presacral space. Surgeries here include repair of rectal prolapse and anterior meningocele, radical perineal prostatectomy, removal of tumors including sacrococcygeal teratoma, and coccygectomy. Perineal hernia is a common complication of coccygectomy in adults, but not in infants and children (see coccygectomy).

The standard surgical technique for repair of perineal hernia uses a prosthetic mesh, but this technique has a high rate of failure due to insufficient anchoring. Promising new techniques to reduce the rate of failure include an orthopedic anchoring system, a gluteus maximus muscle flap, an acellular human dermis graft, and an acellular pig collagen graft.

Triploidy affects approximately 1-2% of pregnancies, but most miscarry early in development. At birth, males with triploidy are 1.5 times more common than females.

Most fetuses with triploidy do not survive to birth, and those that do usually pass within days. As there is no treatment for Triploidy, palliative care is given if a baby survives to birth. If Triploidy is diagnosed during the pregnancy, termination is often offered as an option due to the additional health risks for the mother (preeclampsia, a life-threatening condition, or choriocarcinoma, a type of cancer). Should a mother decide to carry until term or until a spontaneous miscarriage occurs, doctors will monitor her closely in case either condition develops.

Mosaic triploidy has an improved prognosis, but affected individuals have moderate to severe cognitive disabilities.

Empty sella syndrome (abbreviated ESS) is where the pituitary gland shrinks or becomes flattened, filling the sella turcica with cerebrospinal fluid on imaging instead of the normal pituitary. ESS can be found in the diagnostic workup of pituitary disorders, or as an incidental finding when imaging the brain.

If there are symptoms, people with empty sella syndrome can have headaches, as symptoms, which subsides when lying down. Additional symptoms are as follows:

- Abnormality (middle ear ossicles)

- Cryptorchidism

- Dolichocephaly

- Arnold-Chiari type I malformation

- Meningocele

- Patent ductus arteriosus

- Muscular hypotonia

- Platybasia

The lateral meningocele syndrome is a very rare skeletal disorder with facial anomalies, hypotonia and meningocele-related neurologic dysfunction.