Rhombencephalosynapsis

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Rhombencephalosynapsis is a rare genetic brain abnormality of malformation of the cerebellum. The cerebellar vermis is either absent or only partially formed, and fusion is seen in varying degree between the cerebellar hemispheres, fusion of the middle cerebellar peduncles, and fusion of the dentate nuclei. [1] Findings range from mild truncal ataxia, to severe cerebral palsy. [2]

Contents

Rhombencephalosynapsis is a constantly found feature of Gomez-Lopez-Hernandez syndrome. [3] One case of which has shown a co-occurrence with autism-spectrum disorder. [4]

Presentation

Clinical indications range from mild truncal ataxia with unaffected cognitive abilities, to severe cerebral palsy and intellectual disability.

Genetics

An association with mutations in the MN1 gene has been reported in cases of atypical rhomboencephalosynapsis. [5]

Pathology

Rhombencephalosynapsis is a rare brain disorder of malformation of the cerebellum that may be detected on ultrasound of the fetus. The vermis is either absent or partially formed. There is dorsal fusion of the cerebellar hemispheres, fusion of the dentate nuclei, and fusion of the middle cerebellar peduncles. [1] The degree of severity of this disorder is associated with the degree of maldevelopment of the cerebellar vermis. [1]

Aqueductal stenosis commonly exists with the disorder, as does its often resulting hydrocephalus. [1] [6] In some cases additional abnormalities may be present, such as ventriculomegaly (enlarged ventricles), and supratentorial abnormalities. [2]

Diagnosis

Rhombencephalosynapsis can be detected on imaging of the fetus. It is one of the triad of features characteristic of Gomez-Lopez-Hernandez syndrome (GLHS). When detected, signs of GLHS ought to be looked for on post-natal review. Signs include partial alopecia and some facial peculiarities. [7] It is thought that due to the co-occurrence of these two disorders they may have a common etiology. [7]

As a feature of GLHS one case study has shown GLHS to co-occur with autism spectrum disorder. [4]

Epidemiology

As of 2018 only 36 cases of GLHS have been reported. [4]

History

The first case was reported by Heinrich Obersteiner in 1914. [8]

Related Research Articles

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<span class="mw-page-title-main">Joubert syndrome</span> Medical condition

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<span class="mw-page-title-main">Cerebellar vermis</span> Structure connecting the two cerebellar hemispheres

The cerebellar vermis is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways.

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<span class="mw-page-title-main">Hindbrain</span> Part of the embryonic brain

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<span class="mw-page-title-main">Dandy–Walker malformation</span> Congenital malformation of the cerebellar vermis

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<span class="mw-page-title-main">22q13 deletion syndrome</span> Rare genetic syndrome

22q13 deletion syndrome, also known as Phelan–McDermid syndrome (PMS), is a genetic disorder caused by deletions or rearrangements on the q terminal end of chromosome 22. Any abnormal genetic variation in the q13 region that presents with significant manifestations (phenotype) typical of a terminal deletion may be diagnosed as 22q13 deletion syndrome. There is disagreement among researchers as to the exact definition of 22q13 deletion syndrome. The Developmental Synaptopathies Consortium defines PMS as being caused by SHANK3 mutations, a definition that appears to exclude terminal deletions. The requirement to include SHANK3 in the definition is supported by many but not by those who first described 22q13 deletion syndrome.

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<span class="mw-page-title-main">Macrocephaly-capillary malformation</span> Medical condition

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<span class="mw-page-title-main">Pontocerebellar hypoplasia</span> Group of neurodegenerative disorders

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Autosomal recessive cerebellar ataxia type 1 (ARCA1) is a condition characterized by progressive problems with movement. Signs and symptoms of the disorder first appear in early to mid-adulthood. People with this condition initially experience impaired speech (dysarthria), problems with coordination and balance (ataxia), or both. They may also have difficulty with movements that involve judging distance or scale (dysmetria). Other features of ARCA1 include abnormal eye movements (nystagmus) and problems following the movements of objects with their eyes. The movement problems are slowly progressive, often resulting in the need for a cane, walker, or wheelchair.

<span class="mw-page-title-main">Autosomal dominant cerebellar ataxia</span> Medical condition

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<span class="mw-page-title-main">Gómez–López-Hernández syndrome</span> Medical condition

Gómez–López-Hernández syndrome (GLH) or cerebellotrigeminal-dermal dysplasia is a rare neurocutaneous (Phakomatosis) disorder affecting the trigeminal nerve and causing several other neural and physical abnormalities. Gómez–López-Hernández syndrome has been diagnosed in only 34 people. Cases of Gómez–López-Hernández syndrome may be under-reported as other diseases share the characteristics of cerebellar malformation shown in Gómez–López-Hernández syndrome. Gómez–López-Hernández syndrome was first characterized in 1979.

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<span class="mw-page-title-main">Chudley–Mccullough syndrome</span> Medical condition

Chudley–Mccullough syndrome is a rare genetic disorder which is characterized by bilateral congenital hearing loss associated with brain malformations. It is a type of syndromic deafness.

References

  1. 1 2 3 4 Cotes, C; et al. (June 2015). "Congenital basis of posterior fossa anomalies". The Neuroradiology Journal. 28 (3): 238–53. doi:10.1177/1971400915576665. PMC   4757284 . PMID   26246090.
  2. 1 2 Toelle SP, Yalcinkaya C, Kocer N, Deonna T, Overweg-Plandsoen WC, Bast T, et al. (August 2002). "Rhombencephalosynapsis: clinical findings and neuroimaging in 9 children". Neuropediatrics. 33 (4): 209–14. doi:10.1055/s-2002-34498. PMID   12368992.
  3. ↑ Fernández-Jaén A, Fernández-Mayoralas DM, Calleja-Pérez B, Muñoz-Jareño N, Moreno N (January 2009). "Gomez-Lopez-Hernandez syndrome: two new cases and review of the literature". Pediatric Neurology. 40 (1): 58–62. doi:10.1016/j.pediatrneurol.2008.10.001. PMID   19068257.
  4. 1 2 3 Kotetishvili B, Makashvili M, Okujava M, Kotetishvili A, Kopadze T (August 2018). "Co-occurrence of Gomez-Lopez-Hernandez syndrome and Autism Spectrum Disorder: Case report with review of literature". Intractable & Rare Diseases Research. 7 (3): 191–195. doi:10.5582/irdr.2018.01062. PMC   6119670 . PMID   30181940.
  5. ↑ Mak, CCY; et al. (13 December 2019). "MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis". Brain: A Journal of Neurology. 143 (1): 55–68. doi:10.1093/brain/awz379. PMC   7962909 . PMID   31834374.
  6. ↑ Aldinger, KA; et al. (December 2018). "Rhombencephalosynapsis: Fused cerebellum, confused geneticists". American Journal of Medical Genetics. Part C, Seminars in Medical Genetics. 178 (4): 432–439. doi:10.1002/ajmg.c.31666. PMC   6540982 . PMID   30580482.
  7. 1 2 Tan TY, McGillivray G, Goergen SK, White SM (November 2005). "Prenatal magnetic resonance imaging in Gomez-Lopez-Hernandez syndrome and review of the literature". American Journal of Medical Genetics. Part A. 138 (4): 369–73. doi:10.1002/ajmg.a.30967. PMID   16158443. S2CID   11532423.
  8. ↑ Truwit, CL; et al. (1991). "MR imaging of rhombencephalosynapsis: report of three cases and review of the literature". AJNR. American Journal of Neuroradiology. 12 (5): 957–65. PMC   8333516 . PMID   1950929.
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