Holoprosencephaly

(Also see details anomalies of the fetal head)

Briefly, holoprosencephaly is a complex spectrum secondary to absent or incomplete median cleavage of the forebrain and ventricular system, resulting in a monoventricular cavity and abnormal midline structures. In addition to the major abnormalities in the brain, facial deformities are also very common.

Fig1, Fig2, Fig3, Fig4, Fig5, Fig6, Fig7

These deformities are as follows:

  • Orbits:
    • hypotelorism; abnormally close spacing of the orbits
    • cyclopia; single midline orbit
  • Nose:
    • proboscis with absent nose
    • ethmocephaly; hypotelorism; absent nose; proboscis may be single or double or absent
    • cebocephaly; hypotelorism, single nostril nose
  • Upper lip:
    • midline cleft; flat nose; premaxillary agenesis
    • lateral cleft (rare).

Fig 1: Schematic drawing: Facial abnormality related to holoprosencephaly: Ethmocephaly

Fig 2: Schematic drawing: Facial abnormality related to holoprosencephaly: Cyclopia with proboscis

Fig 3: Schematic drawing: Facial abnormality related to holoprosencephaly: Normal face

Fig 4: Schematic drawing: Facial abnormality related to holoprosencephaly: Bilateral clefts

Fig 5: Schematic drawing: Facial abnormality related to holoprosencephaly: Midline cleft

Fig 6: Schematic drawing: Facial abnormality related to holoprosencephaly: Cebocephaly

Fig 5:Holoprosencephaly and proboscis  Transverse scan of the skull showing common ventricle (*) and oblique coronal scan the proboscis (solid circle = thalamus, arrow = orbits, arrowhead = proboscis)

Video clips of proboscis

Proboscis:  Coronal scan of the face showing a proboscis above the cyclopia

Proboscis:  Mid-sagittal scan of the face showing a proboscis above the eye with absent nose

Proboscis (holoprosencephaly): Midline solid mass at the forehead (proboscis) and fused ventricle

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