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Start free with EleplanSemilobar holoprosencephaly
ORPHA:220386Clinical subtype
What it is
A form of holoprosencephaly characterized by fusion of the left and right frontal and parietal lobes with only a posterior interhemispheric fissure. Craniofacial features variably include ocular hypotelorism, midline cleft lip (complete or partial) and a flat nose.
Key facts
- Prevalence
- 1-9 / 100 000 (Europe)
- Age of onset
- Infancy, Neonatal
- Inheritance
- Multigenic/multifactorial, Not applicable
- Classified as
- Clinical subtype
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%
7Common30–79%
41- Abnormal brainstem morphology
- Abnormal hypothalamus physiology
- Abnormality of central motor function
- Abnormality of the autonomic nervous system
- Abnormal morphology of the olfactory bulb
- Abnormal pattern of respiration
- Absent speech
- Anxiety
- Apathy
- Aplasia of the falx cerebri
- Aspiration pneumonia
- Attention deficit hyperactivity disorder
- Atypical behavior
- Bifid uvula
- Central apnea
- Cerebral visual impairment
- Chronic lung disease
- Cleft palate
- Constipation
- Depressed nasal ridge
- Depression
- Dysphagia
- Floppy infant
- Gastroesophageal reflux
- High palate
- Inability to walk
- Intellectual disability
- Irritability
- Lethargy
- Limb dystonia
- Median cleft lip
- Microcephaly
- Neural tube defect
- Oromotor apraxia
- Seizure
- Sensorineural hearing impairment
- Sleep-wake cycle disturbance
- Spasticity
- Specific learning disability
- Temperature instability
- Vomiting
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
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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