holoprosencephaly


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holoprosencephaly

 [hol″o-pros″en-sef´ah-le]
a 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

/holo·pros·en·ceph·a·ly/ (-pros″en-sef´ah-le) developmental failure of cleavage of the prosencephalon with a deficit in midline facial development and with cyclopia in the severe form; sometimes due to trisomy 13.

holoprosencephaly

[hol′ōpros′ensef′əlē]
Etymology: Gk, holos + pro, before, enkephalos, brain
a congenital defect caused by the failure of the prosencephalon to divide into hemispheres during embryonic development. It is characterized by multiple midline facial defects, including cyclopia in severe cases. It can also be caused by an extra chromosome in the 13-15 or D group, manifested as one of many developmental defects. See also trisomy 13. holoprosencephalic, holoprosencephalous, adj.
enlarge picture
Holoprosencephaly: view of dorsal surface

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]

holoprosencephaly (hō´lōpros´ən-sef´əlē),

n a congenital defect caused by the failure of the prosencephalon to divide into hemispheres during embryonic development. It is characterized by multiple midline facial defects, including cyclopia in severe cases.

holoprosencephaly

developmental failure of cleavage of the prosencephalon with a deficit in midline facial development and with cyclopia in the severe form.
References in periodicals archive ?
Noggin null allele mice exhibit a microform of holoprosencephaly.
Holoprosencephaly was defined as a single midline ventricular cavity with failure in the development of midline sagittal structures.
Holoprosencephaly (HPE) is perhaps one of the more complex and captivating congenital brain malformations, with its striking imaging phenotype abnormalities and complex neurological impairment.
Holoprosencephaly (HPE) occurs as a result of a failure of cleavage, septation, or differentiation of the prosencephalon, which is the portion of the embryonic brain that later differentiates into the cerebrum, basal ganglia, and thalamic structure.
1%) with encephalocele, arachnoid cysts, hydrenencephaly and 01 each with exencephaly and holoprosencephaly.
Cerebral malformations were present in 3 children, two patients had Dandy-Walker syndrome and one holoprosencephaly.
Alobar holoprosencephaly and otocephaly in a female infant with a normal karyotype and placental villitis.
Holoprosencephaly (HPE) is the most common structural anomaly of the development of human's forebrain, resulting from incomplete midline cleavage of the prosencephalon, associated with neurologic impairment and dysmorphism of the brain and face, due to disturbance of the delicate balance of signals required for proper separation of the cerebral hemispheres.
Holoprosencephaly (HPE) is a structural anomaly of the brain in which there is failed or incomplete separation of the forebrain early in gestation.
23) In chicken5, 29 and fish, (30) Shh alterations produce deficient middle craniofacial structures--phenotypes that are compatible to the holoprosencephaly syndrome, (31,32) along with labial-palatal fissures.
Alobar holoprosencephaly (arhinencephaly) with median cleft lip and palate: clinical, eletroencephalographic and nosologic considerations.
Alobar holoprosencephaly is the most severe form and usually leads to stillbirth or death shortly after birth.