title: Holoprosencephaly and agnathia spectrum: Presentation of two new patients and review of the literature.
abstract: Holoprosencephaly (HPE), the most common developmental disorder of the human forebrain, is occasionally associated with the spectrum of agnathia, or virtual absence of the mandible. This condition results in a constellation of structural cerebral and craniofacial abnormalities. Here we present two new patients and review 30 patients from the literature with HPE and variants of agnathia. The majority of these patients are female and have the most severe forms of HPE, with cyclopia present more frequently than is usually observed in cohorts of patients with HPE. Also, many patients have additional clinical findings not typical in patients with classic HPE, particularly situs abnormalities. Recent animal studies suggest that the association of HPE and agnathia may relate to alterations in signaling from forebrain and foregut endoderm organizing centers and subsequent first pharyngeal arch development, although present models are inadequate to explain all of the clinical findings of this enigmatic human syndrome. Further research is required to better elucidate the causal and pathogenic basis of this association.
authors.affiliation: Medical Genetics Branch of the National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-3717, USA.
authors.forename: Emily F
authors.initials: EF
authors.lastname: Kauvar
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Solomon
authors.forename: Cynthia J R
authors.initials: CJ
authors.lastname: Curry
authors.forename: Anthonie J
authors.initials: AJ
authors.lastname: van Essen
authors.forename: Nicole
authors.initials: N
authors.lastname: Janssen
authors.forename: Amalia
authors.initials: A
authors.lastname: Dutra
authors.forename: Erich
authors.initials: E
authors.lastname: Roessler
authors.forename: Maximilian
authors.initials: M
authors.lastname: Muenke
mesh_terms: D037881:Aborted Fetus / Q000002:abnormalities; D000293:Adolescent; D019465:Craniofacial Abnormalities / Q000145:classification / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005313:Fetal Death; D016142:Holoprosencephaly / Q000145:classification* / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000175:diagnosis / Q000209:etiology; D008954:Models, Biological; D010641:Phenotype; D011247:Pregnancy