Neural Tube Defects

What are neural tube defects?

Neural tube defects are birth defects which affect the brain and spinal cord. The neural tube is the structure in which the foetus starts to develop during the very early stages of pregnancy; as the foetus develops, the neural tube becomes a more complex structure, which eventually makes up the bones, connective tissue and nerves that form the spinal column and the nervous system. The fusion of the neural tube is usually complete within the first four weeks of pregnancy; however, in babies with neural tube defects, a problem may occur which causes the development to be delayed or abnormal.

Neural tube defects occur when there is an opening in the spinal column or an irregularity which affects the protection of the brain or spinal cord. The brain and spinal cord are usually protected by a fluid known as cerebrospinal fluid and tissue known as meninges; a neural tube defect affects these protective layers and can have serious implications for development and future health.

Neural tube defects affect around 2-3 in every 1,000 live births.

What causes neural tube defects?

In the vast majority of cases, the cause of neural tube defects remains unknown. Research has suggested that there may be possible environmental and genetic factors, which can contribute to neural tube defects and some studies have suggested other possible risk factors. Possible risk factors include:

• Medication: certain types of medication, including valproic acid and carbamezapine, have been associated with an increased risk of have a baby with a neural tube defect.
• Folic acid: a lack of folic acid has been associated with neural tube defects.
• Family history: some studies have indicated a link between family history and increased risk of neural tube defects; however, in around 95 percent of cases, the parents do not have a family history of neural tube defects.
• Health conditions: Chronic health conditions, including diabetes, which affect the mother, may increase the risk of having a baby with a neural tube defect.

Neural tube defects

Types of neural tube defect are usually categorised by being open or closed; this refers to whether or not the defect is covered by skin. Examples of closed neural tube defects include spina bifida occulta. Open neural tube defects include spina bifida meningocele and myelomeningocele.

The most common neural tube defects are spina bifida and anencephaly.

• Spina bifida

There are many different types of spina bifida; the three main forms include spina bifida occulta, spina bifida meningocele and myelomeningocele. Spina bifida occulta is the most common form of the condition and the least serious; it occurs as a result of a small opening in the spinal column. Spina bifida meningocele is the rarest form of spina bifida; it is characterised by the protective membranes being pushed out of the spinal column. Myelomeningocele is the most serious condition and occurs as a result of the membrane and spinal cord being pushed out between the vertebrae; this forms a sac on the back of the baby. The symptoms of spina bifida usually depend on the nature of the condition and the location of the opening on the spinal column. More severe forms of the condition may cause serious health problems and learning difficulties.

• Anencephaly

Anencephaly affects the development of the brain and skull and often results in missing bones and minimal development of the cerebrum (this is the portion of the brain that is responsible for thinking, moving and the senses). Anencephaly is caused by an opening at the base of the skull.

Symptoms of anencephaly include:

• Folded ears
• Missing bones around the front and back of the skull
• Cleft palate
• Congenital heart defects
• Lack of reflexes

In many cases, anencephaly can be diagnosed during pregnancy; antenatal tests including ultrasound scans, blood tests and amniocentesis can detect a range of birth defects, including neural tube defects. In most cases, the baby will be stillborn because the brain is so underdeveloped; those who survive birth sadly die within the first few days.

Less common neural tube defects include:

• Encephaloceles
• Hydranencephaly
• Tethered spinal cord syndrome

What are the effects of neural tube defects?

The effects of neural tube defects depend heavily on the location of the opening and the extent of the damage to the protective tissues and structures surrounding the brain and spinal cord. In many cases of spina bifida, early treatment is very successful and children can grow to live an independent and fulfilling life. In more serious cases, such as anencephaly, very few babies survive past a few days, as the brain is so underdeveloped.

Most children with neural tube defects experience problems relating to learning difficulties and problems with movement and development. Neural tube defects can contribute to the following problems and complications:

• Lack of concentration
• Lack of coordination
• Difficulties with reading
• Difficulty solving problems
• Misshapen bones
• Stiff joints
• Muscle weakness
• Incontinence
• Paralysis (often in the lower limbs)
• Allergies

Treating neural tube defects

Neural tube defects can cause a range of different symptoms so the approach to treatment is multi-faceted. Each child with a neural tube defect is given a multidisciplinary team of professionals, who are able to take care of all aspects of their care. As well as medical specialists, the team usually consists of a physiotherapist, a dietician, an occupational therapist, a speech and language therapist and social workers. Treatment is focused on managing symptoms and encouraging growth and development.

Support for people with neural tube defects

There are numerous charities that specialise in caring for those with neural tube defects, as well as their carers and relatives. These charities are there to offer advice, offer help and support and raise money and awareness to help make life easier for those with these conditions. If you want to talk to somebody about a neural tube defect, you can either go to a member of the care team your GP or contact The Brain and Spine Foundation, ASBAH (Association for Spina Bifida Hydrocephalus) or Contact a Family.

The care team will continue to offer medical care and support for the child but they may require additional help at school and at home; if you are struggling to care for a relative with a neural tube defect, you should ask your social worker about organising additional help or you can contact Carers UK. If you have concerns about your child at school, you should discuss this with their teacher; most schools have a key worker system which enables your child to benefit from the academic, practical and emotional support of a key worker.