Rhombencephalosynapsis: a Viennese Malformation?

Schachenmayr, W; Friede, Reinhard L.

doi:10.1111/j.1469-8749.1982.tb08797.x

Cited by 24 publications

(8 citation statements)

References 2 publications

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“…Other lesions have been reported, such as hypoplasia of the temporal lobes [26,48], and gray matter heterotopias with calciWcations of the frontal lobes [26]. Absence of olfactory bulbs and tracts has been reported by Shachenmayr and Friede [42], but were never observed in our series. Eye or visual pathways anomalies have also been reported, consisting of microphthalmia [26], optic nerve atrophy or hypoplasia [21,58], septo-optic dysplasia [27] and absence of optic chiasm [47], which were not identiWed in any of our cases.…”

Section: Neuropathological Descriptionscontrasting

confidence: 48%

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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 Descriptionscontrasting

confidence: 48%

“…Neuropathological descriptions concern mainly pediatric, 11 cases, from birth to the age of 16 [14,20,21,23,42,48] and four adult cases [20,21,30,58]. Fetal neuropathology has seldom been reported, and to our knowledge, only eight autopsy cases with neuropathological analysis have been described [26,27,[47][48][49].…”

Section: Neuropathological Descriptionsmentioning

confidence: 98%

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

et al. 2008

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“…However, a large majority of patients with RES, and especially GLH, are sporadic, suggesting de novo autosomal dominant mutations as the most common cause (Romanengo et al, 1997;Toelle et al, 2002;Sandalcioglu et al, 2006;Chemli et al, 2007). RES has been associated with other brain abnormalities (Kepes et al, 1969;Michaud et al, 1982;Schachenmayr and Friede, 1982;Isaac and Best, 1987;Savolaine et al, 1991;Truwit et al, 1991;Simmons et al, 1993;Boltenstern et al, 1995;Demaerel et al, 1995;Shaw, 1995;Sergi et al, 1997;Utsunomiya et al, 1998;Sener, 2000;Jellinger, 2002Jellinger, , 2009Toelle et al, 2002;Yachnis, 2002;Boltshauser, 2004;Pavone et al, 2005;Siebert et al, 2005;Chemli et al, 2007;Pasquier et al, 2009), but no large post-natal series exists to determine the spectrum and prevalence of associated imaging features and neurodevelopmental outcomes.…”

Section: Introductionmentioning

confidence: 99%

Rhombencephalosynapsis: a hindbrain malformation associated with incomplete separation of midbrain and forebrain, hydrocephalus and a broad spectrum of severity

Ishak

Dempsey

Shaw

et al. 2012

Brain

139

144

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Rhombencephalosynapsis is a midline brain malformation characterized by missing cerebellar vermis with apparent fusion of the cerebellar hemispheres. Rhombencephalosynapsis can be seen in isolation or together with other central nervous system and extra-central nervous system malformations. Gómez-López-Hernández syndrome combines rhombencephalosynapsis with parietal/temporal alopecia and sometimes trigeminal anaesthesia, towering skull shape and dysmorphic features. Rhombencephalosynapsis can also be seen in patients with features of vertebral anomalies, anal atresia, cardiovascular anomalies, trachea-oesophageal fistula, renal anomalies, limb defects (VACTERL) association. Based on a comprehensive evaluation of neuroimaging findings in 42 patients with rhombencephalosynapsis, we propose a spectrum of severity, ranging from mild (the partial absence of nodulus, anterior and posterior vermis), to moderate (the absence of posterior vermis with some anterior vermis and nodulus present), to severe (the absence of posterior and anterior vermis with some nodulus present), to complete (the absence of the entire vermis including nodulus). We demonstrate that the severity of rhombencephalosynapsis correlates with fusion of the tonsils, as well as midbrain abnormalities including aqueductal stenosis and midline fusion of the tectum. Rhombencephalosynapsis is also associated with multiple forebrain abnormalities including absent olfactory bulbs, dysgenesis of the corpus callosum, absent septum pellucidum and, in rare patients, atypical forms of holoprosencephaly. The frequent association between rhombencephalosynapsis and aqueductal stenosis prompted us to evaluate brain magnetic resonance images in other patients with aqueductal stenosis at our institution, and remarkably, we identified rhombencephalosynapsis in 9%. Strikingly, subjects with more severe rhombencephalosynapsis have more severely abnormal neurodevelopmental outcome, as do subjects with holoprosencephaly and patients with VACTERL features. In summary, our data provide improved diagnostic and prognostic information, and support disruption of dorsal-ventral patterning as a mechanism underlying rhombencephalosynapsis.

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“…Associated anomalies of the cerebral hemispheres have been observed (Boltenstern, Konrad, Jost, Uder, & Kujat, 1995;Demaerel et al, 1995;Montull, Mercader, Peri, Martinez Ferri, & Bonaventura, 2000;Scroop, Sage, & Voyvodic, 2000), as have facial and non-cranial abnormalities (Aydingoz, Cila, & Aktan, 1997;Michaud, Mizrahi, & Urich, 1982;Sener, 2000;Truwit, Barkovich, Shanahan, & Maroldo, 1991). Some patients die early in life due to co-existing anomalies or illnesses (Savolaine et al, 1991;Schachenmyr & Friede, 1982;Yachnis, 2002).…”

mentioning

confidence: 99%

“…Between Obersteiner's original WWI era description of RS (Verri, Uggetti, Vallero, Ceroni, & Federico, 2000) and the advent of MRI, only about one dozen cases were reported (Michaud et al, 1982;Truwit et al, 1991). Only approximately 35 cases diagnosed by means of MRI have been described (Auber & Barkovich, 1995;Aydingoz et al, 1997;Boltenstern et al, 1995;Demaerel et al, 1995;Guyot et al, 2000;Romanengo, Tortori-Donati, & Di Rocco, 1997;Savolaine et al, 1991;Schachenmyr & Friede, 1982;Scroop et al, 2000;Simmons, Damiano, & Truwit, 1993;Toelle et al, 2002;Truwit et al, 1991;Utsunomiya et al, 1998;Verri et al, 2000).…”

mentioning

confidence: 99%

Rhombencephalosynapsis

2020

Definitions

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Rhombencephalosynapsis (RS) is a rare congenital disorder characterized principally by agenesis/hypogenesis of the cerebellar vermis and fusion of the dentate nuclei and cerebellar hemispheres. Fusion of the peduncles and colliculi is common, and associated anomalies of the cerebral hemispheres also can be present. Only about 50 cases with RS have been described and the majority of these have been children. While the literature suggests that RS often is associated with behavioral and/or intellectual impairment, no previous report has described overall neuropsychological functioning. This report describes an employed male who was diagnosed with RS by MRI at age 55. The neurological examination revealed only subtle sensory-motor abnormalities and the results of the neuropsychological evaluation were generally within normal limits, with the exception of poor immediate visual memory and motor dexterity. These findings suggest RS is not inevitably associated with substantial cognitive impairment.

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Rhombencephalosynapsis: a Viennese Malformation?

Cited by 24 publications

References 2 publications

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

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

Rhombencephalosynapsis: a hindbrain malformation associated with incomplete separation of midbrain and forebrain, hydrocephalus and a broad spectrum of severity

Rhombencephalosynapsis

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