Congenital Abnormality
holoprosencephaly
Subclass of:
Congenital chromosomal disease;
Multiple congenital anomalies;
Agenesis of corpus callosum;
Craniofacial Abnormalities
Definitions related to holoprosencephaly:
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A rare disorder characterized by the failure of the forebrain to divide into distinct hemispheres. It is associated with craniofacial abnormalities, developmental abnormalities, and seizures.NCI ThesaurusU.S. National Cancer Institute, 2021
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Anterior midline brain, cranial, and facial malformations resulting from the failure of the embryonic prosencephalon to undergo segmentation and cleavage. Alobar prosencephaly is the most severe form and features anophthalmia; cyclopia; severe INTELLECTUAL DISABILITY; CLEFT LIP; CLEFT PALATE; SEIZURES; and microcephaly. Semilobar holoprosencepaly is characterized by hypotelorism, microphthalmia, coloboma, nasal malformations, and variable degrees of INTELLECTUAL DISABILITY. Lobar holoprosencephaly is associated with mild (or absent) facial malformations and intellectual abilities that range from mild INTELLECTUAL DISABILITY to normal. Holoprosencephaly is associated with CHROMOSOME ABNORMALITIES.NLM Medical Subject HeadingsU.S. National Library of Medicine, 2021
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Holoprosencephaly is a structural anomaly of the brain in which the developing forebrain fails to divide into two separate hemispheres and ventricles.Human Phenotype Ontology (HPO)The Human Phenotype Ontology Project, 2021
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Incomplete development of the forebrain that may be associated with midfacial anomalies and pituitary hormone deficiencies.NICHD Pediatric TerminologyU.S. National Cancer Institute, 2021
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Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family. Nonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms. People with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in...MedlinePlus GeneticsU.S. National Library of Medicine, 2021
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Holoprosencephaly is a structural malformation of the brain that results from complete or incomplete nonseparation of the prosencephalon (forebrain). Classification Holoprosencephaly is categorized into 4 subtypes: alobar holoprosencephaly, semilobar holoprosencephaly, lobar holoprosencephaly, and a middle interhemispheric fusion variant...WebMD, 2019
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Holoprosencephaly is an abnormality of brain development in which the brain doesn't properly divide into the right and left hemispheres. The condition can also affect development of the head and face. There are 4 types of holoprosencephaly, distinguished by severity. From most to least severe, the 4 types are alobar, semi-lobar, lobar,...National Center for Advancing Translational Sciences
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