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Start free with EleplanAgnathia-holoprosencephaly-situs inversus syndrome
ORPHA:990Malformation syndrome
What it is
An extremely rare and fatal association syndrome, characterized by absence of the mandible, cerebral malformations with facial anomalies related to a defect in cleavage in the embryonic brain (e.g. synophthalmia, malformed and low-set ears fused in midline (otocephaly), agenesis of the olfactory bulbs, microstomia, hypoglossia/aglossia) and situs inversus partialis or totalis.
Key facts
- Prevalence
- <1 / 1 000 000 (Europe)
- Age of onset
- Antenatal, Neonatal
- Inheritance
- Autosomal dominant, Autosomal recessive, Not applicable
- Classified as
- Malformation syndrome
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
Very common80–99%
19- Abnormal cranial nerve morphology
- Abnormality of the eye
- Absent nares
- Agenesis of corpus callosum
- Aplasia/Hypoplasia involving the nose
- Aplasia/Hypoplasia of the cerebellum
- Aplasia/Hypoplasia of the eyebrow
- Cyclopia
- Holoprosencephaly
- Hypoplasia of penis
- Mandibular aplasia
- Microglossia
- Narrow internal auditory canal
- Narrow mouth
- Polyhydramnios
- Posteriorly rotated ears
- Respiratory distress
- Situs inversus totalis
- Synotia
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.
Genes
1 modifying gene — variants that can change how the disease behaves, not cause it
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
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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