GTR Home > Conditions/Phenotypes > Holoprosencephaly 2

Disease characteristics

Excerpted from the GeneReview: Holoprosencephaly Overview
Holoprosencephaly (HPE) is a structural anomaly of the brain in which there is failed or incomplete separation of the forebrain early in gestation. Classic HPE encompasses a continuum of brain malformations including (in order of decreasing severity): alobar, semilobar, lobar, and middle interhemispheric variant (MIHV) type HPE; a septopreoptic type has also been described. Other CNS abnormalities not specific to HPE may also occur. HPE is accompanied by a spectrum of characteristic craniofacial anomalies in approximately 80% of individuals with HPE. Developmental delay is present in virtually all individuals with the HPE spectrum of CNS anomalies. Seizures and pituitary dysfunction are common. Most affected fetuses do not survive; severely affected children typically do not survive beyond early infancy, while a significant proportion of more mildly affected children survive past 12 months. Mildly manifesting individuals without appreciable brain anomalies on conventional neuroimaging may be described as having “microform” HPE.

Available tests

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Associated genes

Clinical features

  • Agenesis of corpus callosum
  • Intellectual disability
  • Microcephaly
  • Midface retrusion
  • Malar flattening
  • Seizure
  • Constipation
  • Median cleft lip and palate
  • Submucous cleft hard palate
  • Bifid uvula
  • Microphthalmos
  • Hypotelorism
  • Adrenal hypoplasia
  • Diabetes insipidus
  • Muscular hypotonia
  • Global developmental delay
  • Cerebellar hypoplasia
  • Holoprosencephaly
  • Scoliosis
  • Absent nasal septal cartilage
  • Single median maxillary incisor
  • Cyclopia
  • Aplasia of the nose
  • Anterior pituitary agenesis
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