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What is iniencephaly?

Iniencephaly is a rare birth defect caused by improper closure of the neural tube (the part of a human embryo that becomes the brain and spinal cord) during fetal development. The defect results in extreme retroflexion (backward bending) of the head combined with severe distortion of the spine.

Diagnosis is made immediately after birth because an infant's head is so severely bent backward that the face looks upward. In most infants, the neck is absent and the skin of the face is connected directly to the skin of the chest, while the scalp is directly connected to the skin of the back. Most infants with iniencephaly have additional birth defects, such as:

  • anencephaly (in which major sections of the brain fail to form)
  • cephalocele (in which part of the cranial contents protrudes from the skull)
  • cyclopia (in which the two cavities of the eyes fuse into one)

Additional birth defects include the lack of a lower jawbone or a cleft lip and palate. Other parts of the body may be affected, and infants can have cardiovascular disorders, diaphragmatic hernias, and gastrointestinal malformations.

For reasons that are still unknown, the disorder is more common among females. No single gene has been identified as the cause for iniencephaly, or any of the neural tube defects. Scientists think these defects have complex causes, mostly likely a mix of genetic and environmental factors.

The outlook for infants with iniencephaly is extremely poor. Newborns seldom survive much past childbirth. The distortions of the baby's body also pose a danger to the mother's life during delivery. 

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with iniencephaly?

Iniencephaly is considered a rare disease, which often means there is not much information known about it. This is usually the case because doctors and researchers do not see many people with iniencephaly, which makes it hard to learn from them through observations or large studies.

Consider participating in a clinical trial so clinicians and scientists can learn more about iniencephaly and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with iniencephaly at

Where can I find more information about iniencephaly?

The following resources may provide more information:

March of Dimes
Phone: 888-663-4637

National Organization for Rare Disorders (NORD)
Phone: 203-744-0100 or 800-999-6673


Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.