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Journal of Clinical and Diagnostic... Sep 2015Otocephaly is a rare malformation characterized by the association of agnathia (agenesis of mandible) or mandibular hypoplasia, melotia (anteromedial malposition of...
Otocephaly is a rare malformation characterized by the association of agnathia (agenesis of mandible) or mandibular hypoplasia, melotia (anteromedial malposition of ears), microstomia (small mouth), aglossia or microglossia (absent or rudimentary tongue). This rare anomaly of the ventral portion of first brachial arch is a consequence of failure of migration of neural crest cells from hind brain. It leads to the development of maxillary and mandibular prominences and starts to develop at the fourth and fifth week of gestation. We hereby present the autopsy findings of a fetus of 28 weeks gestation abortus having otocephaly without holoprosencephaly.
PubMed: 26500912
DOI: 10.7860/JCDR/2015/13636.6444 -
Canadian Journal of Comparative... May 1964An inherited low-grade otocephaly in a strain of Beagles was studied. All cases were "mild" with partial agnathia a constant feature in the adult animal. One case of...
An inherited low-grade otocephaly in a strain of Beagles was studied. All cases were "mild" with partial agnathia a constant feature in the adult animal. One case of high-grade otocephaly with aprosopus was recorded in an outcrossed animal. Neonatal mortalities in the low-grade type were associated with gross patency of the parietal fontanelle and hydrocephaly. Enlarged lateral ventricles were found in adult dogs, associated with incomplete union of the cranial sutures and occasional membranous-like paietal bone replacement over the patent fontanelle. Partial agnathia was not obvious in the neonate, but became apparent during postnatal skeletal development. The major anatomical differences in the skulls of these dogs were compared with normal Beagles. Malocclusion of the lower mandible and teeth against the upper jaw during development may have resulted in changes in length and width of the upper jaw and certain cranial structures. It was thought that the maloccluding lower jaw acted as a wedge against the upper jaw during mastication and these abnormal pressures, transmitted in an upward, forward, and outward direction, caused lengthening and widening of the palatine and temporal bones, and lengthening of the premaxilla and nasal bones. The nasopharyngeal meatus and palatine fissures were narrower and elongated. The pterygoid processes were pulled into a more horizontal position. It was suggested that a primary inherited abnormality may cause secondary changes in contiguous structures during development, and differentiation between primary (genetic) and secondary (acquired) anatomical abnormalities should be considered.
PubMed: 17649505
DOI: No ID Found -
Ultrasound in Obstetrics & Gynecology :... Apr 2007
Topics: Abnormalities, Multiple; Abortion, Eugenic; Craniofacial Abnormalities; Female; Humans; Magnetic Resonance Imaging; Pregnancy; Pregnancy Trimester, Second; Ultrasonography, Prenatal
PubMed: 17330829
DOI: 10.1002/uog.3956 -
The Cornell Veterinarian Apr 1964
Topics: Abnormalities, Severe Teratoid; Animals; Congenital Abnormalities; Craniofacial Abnormalities; Dog Diseases; Dogs; Ear Deformities, Acquired; Ear, External; Epilepsy; Genetics; Mandible; Skull
PubMed: 14140877
DOI: No ID Found -
PloS One 2014Disruption of the Hedgehog signaling pathway has been implicated as an important molecular mechanism in the pathogenesis of fetal alcohol syndrome. In severe cases, the...
Disruption of the Hedgehog signaling pathway has been implicated as an important molecular mechanism in the pathogenesis of fetal alcohol syndrome. In severe cases, the abnormalities of the face and brain that result from prenatal ethanol exposure fall within the spectrum of holoprosencephaly. Single allele mutations in the Hh pathway genes Sonic Hedgehog (SHH) and GLI2 cause holoprosencephaly with extremely variable phenotypic penetrance in humans. Here, we tested whether mutations in these genes alter the frequency or severity of ethanol-induced dysmorphology in a mouse model. Timed pregnancies were established by mating Shh(+/-) or Gli2(+/-) male mice backcrossed to C57BL/6J strain, with wildtype females. On gestational day 7, dams were treated with two i.p. doses of 2.9 g/kg ethanol (or vehicle alone), administered four hrs apart. Fetuses were then genotyped and imaged, and the severity of facial dysmorphology was assessed. Following ethanol exposure, mean dysmorphology scores were increased by 3.2- and 6.6-fold in Shh(+/-) and Gli2(+/-) groups, respectively, relative to their wildtype littermates. Importantly, a cohort of heterozygous fetuses exhibited phenotypes not typically produced in this model but associated with severe holoprosencephaly, including exencephaly, median cleft lip, otocephaly, and proboscis. As expected, a correlation between the severity of facial dysmorphology and medial forebrain deficiency was observed in affected animals. While Shh(+/-) and Gli2(+/-) mice have been described as phenotypically normal, these results illustrate a functional haploinsufficiency of both genes in combination with ethanol exposure. By demonstrating an interaction between specific genetic and environmental risk factors, this study provides important insights into the multifactorial etiology and complex pathogenesis of fetal alcohol syndrome and holoprosencephaly.
Topics: Animals; Crosses, Genetic; Ethanol; Female; Fetal Alcohol Spectrum Disorders; Genotype; Hedgehog Proteins; Holoprosencephaly; Kruppel-Like Transcription Factors; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mutation; Pregnancy; Prosencephalon; Signal Transduction; Zinc Finger Protein Gli2
PubMed: 24586787
DOI: 10.1371/journal.pone.0089448 -
Genes & Development Nov 1995The anterior part of the vertebrate head expresses a group of homeo box genes in segmentally restricted patterns during embryogenesis. Among these, Otx2 expression...
The anterior part of the vertebrate head expresses a group of homeo box genes in segmentally restricted patterns during embryogenesis. Among these, Otx2 expression covers the entire fore- and midbrains and takes place earliest. To examine its role in development of the rostral head, a mutation was introduced into this locus. The homozygous mutants did not develop structures anterior to rhombomere 3, indicating an essential role of Otx2 in the formation of the rostral head. In contrast, heterozygous mutants displayed craniofacial malformations designated as otocephaly; affected structures appeared to correspond to the most posterior and most anterior domains of Otx expression where Otx1 is not expressed. The homo- and heterozygous mutant phenotypes suggest Otx2 functions as a gap-like gene in the rostral head where Hox code is not present. The evolutionary significance of Otx2 mutant phenotypes was discussed for the innovation of the neurocranium and the jaw.
Topics: Abnormalities, Multiple; Animals; Base Sequence; Ear; Embryo, Mammalian; Epithelium; Eye Abnormalities; Gene Expression Regulation, Developmental; Gestational Age; Haploidy; Head; Heterozygote; Homeodomain Proteins; Homozygote; Jaw Abnormalities; Mice; Mice, Transgenic; Molecular Sequence Data; Mutation; Nerve Tissue Proteins; Nervous System Malformations; Nose; Otx Transcription Factors; Phenotype; Trans-Activators
PubMed: 7590242
DOI: 10.1101/gad.9.21.2646 -
Ultrasound in Obstetrics & Gynecology :... Jun 2011
Topics: Abortion, Induced; Female; Holoprosencephaly; Humans; Imaging, Three-Dimensional; Infant, Newborn; Male; Pregnancy; Prenatal Diagnosis; Ultrasonography, Prenatal
PubMed: 21465602
DOI: 10.1002/uog.9009 -
Molecular Syndromology Dec 2014The 22q11.2 deletion syndrome (22q11DS) is thought to be a contiguous gene syndrome caused by haploinsufficiency for a variable number of genes with overlapping function...
The 22q11.2 deletion syndrome (22q11DS) is thought to be a contiguous gene syndrome caused by haploinsufficiency for a variable number of genes with overlapping function during the development of the craniofacial, pharyngeal and cardiac structures. The complexity of genetic and developmental anomalies resulting in 22q11DS has made attributing causation to specific genes difficult. The CRKL gene resides within the common 3-Mb region, most frequently affected in 22q11DS, and has been shown to play an essential role in the development of tissues affected in 22q11DS. Here, we report the characterisation of a mouse strain we named 'snoopy', harbouring a novel Crkl splice-site mutation that results in a loss of Crkl expression. The snoopy strain exhibits a variable phenotype that includes micrognathia, pharyngeal occlusion, aglossia and holoprosencephaly, and altered retinoic acid and endothelin signalling. Together, these features are reminiscent of malformations occurring in auriculocondylar syndrome and agnathia-otocephaly complex, 2 conditions not previously associated with the CRKL function. Comparison of the features of a cohort of patients harbouring small 22q11.2 deletions centred over the CRKL gene, but sparing TBX1, highlights the role of CRKL in contributing to the craniofacial features of 22q11DS. These analyses demonstrate the central role of Crkl in regulating signalling events in the developing oropharyngeal complex and its potential to contribute to dysmorphology.
PubMed: 25565927
DOI: 10.1159/000368865 -
Ultrasound in Obstetrics & Gynecology :... Jan 2002To investigate the prenatal appearance of the holoprosencephaly spectrum.
OBJECTIVE
To investigate the prenatal appearance of the holoprosencephaly spectrum.
METHODS
A database of 1750 fetuses with congenital anomalies identified by ultrasound was prospectively collected from 1987 to 2000. Among them, 30 cases (1.7%) with holoprosencephaly were prenatally identified and described.
RESULTS
The prevalence of holoprosencephaly in the Health Region of the National Center for Fetal Medicine in Norway was 1.26 : 10 000; the sex distribution (male : female) was 1.4 : 1. Holoprosencephaly was found in one dichorionic twin pregnancy and one pair of conjoined twins. Among the 30 cases of holoprosencephaly, 18 were alobar, five were semilobar, two were lobar, two were lobar variants, and three were anencephalic. The facial features varied considerably. Sixty-seven per cent (20/30) had associated structural anomalies that were not related to the cerebral and facial holoprosencephaly condition. Thirty-seven per cent (11/30) had detectable chromosome aberrations and 23% (7/30) had nonchromosomal syndromal origin. The size or shape of the head was abnormal in 83% (25/30) of holoprosencephaly cases.
CONCLUSION
This study indicates that holoprosencephaly represents a heterogeneous entity with different etiologies and clinical appearances. The fact that holoprosencephaly features are found associated with particular conditions such as fronto-nasal dysplasia (2/30; 6.7%), agnathia-otocephaly (3/30; 10%), and anencephaly (3/30; 10%), suggests that these may be underreported conditions in other large holoprosencephaly series.
Topics: Abnormalities, Multiple; Adolescent; Adult; Female; Holoprosencephaly; Humans; Hypertelorism; Karyotyping; Male; Norway; Pregnancy; Ultrasonography, Prenatal
PubMed: 11851965
DOI: 10.1046/j.0960-7692.2001.00154.x -
Genes To Cells : Devoted To Molecular &... Nov 1996We previously reported that the homozygous mutation of Otx2 gene, a mouse cognate of the Drosophila head gap gene orthodenticle, causes failure in the development of the...
BACKGROUND
We previously reported that the homozygous mutation of Otx2 gene, a mouse cognate of the Drosophila head gap gene orthodenticle, causes failure in the development of the rostral head anterior to rhombomere 3, which may correspond to earlier Otx2 expression in cells destined for the anterior mesoendoderm. At the same time, the Otx2 heterozygous mutation displayed a phenotype characterized as otocephaly, probably related to expression in the anterior neuroectoderm at the subsequent pharyngula stage. Defects were characteristic in the most anterior and posterior regions of Otx2 expression where Otx1, another mouse cognate of orthodenticle, is not or weakly expressed. They were not found in the region where Otx1 is expressed.
RESULTS
In the present work, Otx1 null mutant mice were generated by gene targeting in embryonic stem cells. No defects were apparent in the regionalization of the early embryonic rostral brain. The newborn brain defects were subtle and most likely related to later Otx1-unique expression. Otx1 and Otx2 double heterozygous mutant brains, however, exhibited marked defects throughout the fore- and midbrains, where defects were not apparent with a single mutation alone.
CONCLUSIONS
Otx1 and Otx2 play synergistic roles in the development of the forebrain and midbrain where both genes are expressed.
Topics: Animals; Base Sequence; Body Patterning; Head; Homeodomain Proteins; Mice; Mutation; Nerve Tissue Proteins; Otx Transcription Factors; Phenotype; Prosencephalon; Trans-Activators; Transcription Factors
PubMed: 9077465
DOI: 10.1046/j.1365-2443.1996.900288.x