holoprosencephaly

holoprosencephaly

 [hol″o-pros″en-sef´ah-le] a anomaly" >developmental anomaly consisting of failure of cleavage of the prechordal mesoderm with a deficit in the forebrain and midline facial development; in the severe form there may be cyclopia. It is sometimes associated with trisomy 13 syndrome.The facial features in holoprosencephaly. The eyes are close together and there is a midline cleft lip. From Mueller and Young, 2001.

hol·o·pros·en·ceph·a·ly

(hol'ō-pros-en-sef'ă-lē), Impaired midline cleavage of the embryonic forebrain resulting in a wide spectrum of facial features from cyclopia with proboscis above the single eye at the most severe form to ocular hypertelorism and single central upper incisor at the mildest form. This spectrum of disorders is associated with chromosomal aberrations involving chromosomes 2, 3, 7, 13, 18 and 21. [holo- + G. prosō, forward, + enkephalos, brain]

holoprosencephaly

A disorder in which the developing forebrain fails to correctly separate into right and left hemispheres, which is accompanied by facial deformities.
Molecular pathology
Holoprosencephaly is attributed to mutations of the SHH gene.

hol·o·pros·en·ceph·a·ly

(hol'ō-pros-en-sef'ă-lē) Failure of the forebrain or prosencephalon to divide into hemispheres or lobes; cyclopia occurs in the severest form. It is often accompanied by a deficit in midline facial development. [holo- + G. prosō, forward, + enkephalos, brain]

hol·o·pros·en·ceph·a·ly

(hol'ō-pros-en-sef'ă-lē) Failure of the forebrain or prosencephalon to divide into hemispheres or lobes; cyclopia occurs in the severest form. [holo- + G. prosō, forward, + enkephalos, brain]