Iniencephaly

What it is

A rare neural tube defect characterized by an abnormally short neck, with extreme retroflexion of the head and upward turned face resulting from involvement of the occiput and the inion, which are variably combined with rachischisis of the upper cervical and thoracic spine, leading to the incomplete closure of the vertebral arches and/or even their absence. Patients frequently present with malformations of the central nervous system (spina bifida and/or anencephaly), marked lordosis, and appear to have no neck as the skin of the head is continuous with the chest and the back.

Key facts

Prevalence

1-5 / 10 000 (at birth, Europe)

Age of onset

Infancy, Neonatal

Inheritance

Multigenic/multifactorial, Not applicable

Classified as

Morphological anomaly

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references