Rhombencephalosynapsis and a Chiari II Malformation

Şener, R. N.; Dzelzīte, Sarmīte

doi:10.1097/00004728-200303000-00026

Cited by 23 publications

(12 citation statements)

References 12 publications

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“…At last, we identiWed associated neural tube defects in three cases. Neural tube defects have never been previously reported in fetuses, and only in one adult and two pediatric cases, consisting of RS and cervicothoracic or lumbosacral myelomeningocele [40,46], but not of encephalocele as in our three fetuses.…”

Section: Neuropathological Descriptionsmentioning

confidence: 43%

“…Other features have also been described, such as malrotated hippocampi, hypoplastic chiasm, fused cerebral peduncles and thalami [2,9,32,34,54], parietal and temporo-parietal cortical dysplasia [32,33], and schizencephalic cleft [33]. Using MRI, associated Dandy-Walker malformation has been observed in four fetuses [36,45] and Chiari I or II malformations have also been reported in two children [46,54], but these malformations were not identiWed using prenatal US or MRI in our cases.…”

Section: Clinical and Mri Diagnosismentioning

confidence: 59%

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Rhombencephalosynapsis and related anomalies: a neuropathological study of 40 fetal cases

et al. 2008

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Rhombencephalosynapsis is an uncommon cerebellar malformation deWned by vermian agenesis with fusion of the hemispheres and of the dentate nuclei. Embryologic and genetic mechanisms are still unknown, and to date, no animal models are available. Ultrasound diagnosis is generally suspected after 22 weeks of gestation, and usually the abnormality is suggested by ventriculomegaly. Morphological analysis of 40 fetuses after medical termination of pregnancy allowed us to conWrm that rhombencephalosynapsis was always associated with other brain abnormalities or malformations: Purkinje cell heterotopias, fusion of colliculi, forking and/or atresia of the aqueduct and of the third ventricle resulting in a fusion of the thalami, agenesis of the corpus callosum, lobar holoprosencephaly and neural tube defects. Pons and medulla were very infrequently abnormal. Furthermore, complete autopsy made it possible to separate either pure neurologic phenotypes, or associated with extraneural anomalies from syndromic forms: Gomez-Lopez-Hernandez syndrome (1 case) and VACTERL-H syndrome (6 cases). The number of our fetal cases strongly suggests that VACTERL-H association related with rhombencephalosynapsis emerges as a non-random association. Furthermore, recurrence and consanguinity were noted in two diVerent families, which argue for a sporadic or inherited cause. From our results, it could be suggested that rhombencephalosynapsis may be due to defective genes regulating formation of the roof plate and the development of midline cerebellar primordium at the junction of the mesencephalon and of the Wrst rhombomere.

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Section: Neuropathological Descriptionsmentioning

confidence: 43%

Section: Clinical and Mri Diagnosismentioning

confidence: 59%

Rhombencephalosynapsis and related anomalies: a neuropathological study of 40 fetal cases

et al. 2008

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“…RES has been reported previously in association with Chiari II malformations [Sener and Dzelzite 2003; Wan et al, 2005]; however, it also has been suggested that a small posterior fossa and compression of the cerebellar hemispheres can mimic the appearance of RES [Guntur Ramkumar et al, 2010]. Therefore, we cannot dismiss the possibility that the RES diagnosed in two individuals with Chiari II malformations in this study is not a real observation.…”

Section: Discussionmentioning

confidence: 55%

Recurrent partial rhombencephalosynapsis and holoprosencephaly in siblings with a mutation of ZIC2

Ramocki

Scaglia

Stankiewicz

et al. 2011

American J of Med Genetics Pt A

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Rhombencephalosynapsis (RES) is a rare congenital brain malformation typically identified by magnetic resonance imaging and characterized by fusion of the cerebellar hemispheres and dentate nuclei and vermian agenesis or hypogenesis. Although RES is frequently found in conjunction with other brain malformations and/or congenital anomalies, no specific molecular etiology has been discovered to date and no animal models exist. We identified two half sisters with alobar or semi-lobar holoprosencephaly (HPE) and partial RES, suggesting that genes linked to HPE may also contribute to RES. A deletion of seven base pairs in exon one of the ZIC2 gene (c.392_98del7) was identified in each of the two half sisters with HPE and partial RES. To identify genetic causes of RES and to assess whether genes identified in HPE have a role in RES, we tested 11 additional individuals with RES by high resolution chromosome analysis, chromosomal microarray analysis, and sequencing of four HPE genes. No mutations in ZIC2 or in other genes that cause HPE were identified, suggesting that mutation of ZIC2 is a rare cause of, or contributor to, rhombencephalosynapsis associated with HPE. In addition, an individual with a complex rearrangement of chromosome 22q13.3 and RES was identified, suggesting the presence of a dosage-sensitive gene that may contribute to RES in this region.

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“…We wonder if the cerebellar herniation in previously reported similar cases [4, 10] was vermian rather than tonsillar. We also wonder if the cases like these represent another description of abnormality as happens in Chiari type II malformation, rather than a new abnormality of hindbrain and spine as has been suggested [10]. This raises an important question of whether PRECS can be diagnosed with Chiari type II malformation in presence of cerebellar vermian herniation (Figs.…”

Section: Discussionmentioning

confidence: 93%

“…The association of Chiari type II malformation and RECS has been suggested before [10] and their coexistence has been thought of as a "new" abnormality of hindbrain and spine [10]. It is not clear if there is any significant common ground for these abnormalities with apparently different embryogenesis.…”

Section: Discussionmentioning

confidence: 99%