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|Classification and external resources|
Cerebellar hypoplasia is a heterogeneous group of disorder of cerebellar maldevelopment presenting as early onset non progressive ataxia, hypotonia, and motor learning disability. Various causes has been incriminated like hereditary, metabolic, toxic and viral agents. First reported by Crouzon in 1929. In 1940 an unclaimed body came for dissection in London Hospital and was discovered to have no cerebellum. This unique case was appropriately named "human brain without a cerebellum" and was used every year in the Department of Anatomy at Cambridge University in a neuroscience course for medical students.
Following clinical report by Crouzon in 1929 Sarrouy reported 2 pairs of sibs with congenital cerebellar hypoplasia in 1958. However pons, pyramidal tract and corpus callosum were also involved in these cases. Wichman et al. in 1985 reported three sibling pairs with congenital cerebellar hypoplasia. "All six children presented in the first years of life with delays in motor and language development. All patients showed cerebellar and/or vermal dysfunction and, on formal psychometric testing, cognitive abilities ranged from normal to moderately retarded. Abnormalities on CT scan ranged from prominent valleculla to an enlarged cisterna magna with hypoplasia of the cerebellar hemispheres and vermis. The pedigrees are consistent with autosomal recessive inheritance." Mathews KD, in 1989 also reported two cases of cerebellar hypoplasia in a family with unaffected parents suggestive of autosomal recessive inheritance. The frequency and importance of the evaluation of the posterior fossa have increased significantly over the past 20 years owing to advances in neuroimaging with frequent reporting of posterior fossa malformation.
Classification systems for malformations of the cerebellum are varied and are constantly being revised as greater understanding of the underlying genetics and embryology of the disorders is uncovered. A classification proposed by Patel S in 2002 divides cerebellar malformations in two broad groups; those with cerebellar hypoplasia and; those with cerebellar dysplasia.
- I. Cerebellar hypoplasia
- A. Focal hypoplasia
- 1. Isolated vermis
- 2. One hemisphere hypoplasia
- B. Generalized hypoplasia
- 1. With enlarged fourth ventricle (“cyst,”), Dandy-Walker continuum
- 2. Normal fourth ventricle (no “cyst”)
- a. With normal pons
- b. With small pons i. Normal foliation
- a) Pontocerebellar hypoplasias of Barth, types I and II
- b) Cerebellar hypoplasias, not otherwise specified
- A. Focal hypoplasia
Signs and Symptoms
Three dimensional (3D) T1W, Axial, coronal, sagittal imaging is excellent for differentiation between gray matter and white matter acquisition of high-resolution anatomic information.T2W, Axial and coronal imaging for acquisition of high-resolution anatomic information; delineation of cortex, white matter, and gray matter nuclei. Diffusion tensor, axial imaging is used for evaluation of white matter microstructural integrity, identification of white matter tracts. CISS, axial + MPR imaging for evaluation of cerebellar folia, cranial nerves, ventricles, and foramina. Susceptibility weighted axial scan for Identification and characterization of hemorrhage, blood products, calcification, and iron accumulation.
There is no standard course of treatment for cerebellar hypoplasia. Treatment depends upon the underlying disorder and the severity of symptoms. Generally, treatment is symptomatic and supportive. Balance rehabilitation techniques may benefit those experiencing difficulty with balance. Treatment is based on the underlying disorder and the symptom severity. Therapies include physical, occuptational, speech/language, visual, psych/ behavioral meds, special education.
The prognosis of this developmental disorder is highly based on the underlying disorder. Cerebellar hypoplasia may be progressive or static in nature. Some cerebellar hypoplasia resulting from congenital brain abnormalities/malformations are not progressive. Progressive cerebellar hypoplasia is known for having poor prognosis, but in cases where this disorder is static, prognosis is better.
- Crouzon, O (1929). "Atrophie cerebelleuse idiotique, in Etudes sur les Maladies Familiales Nerveuses et Dystrophiques.". Paris: Masson Pp. 90-111.
- Lemon, R. N., & Edgley, S. A. (2010). Life without a cerebellum. Oxford journals, 133(3), 652-654. Retrieved from http://brain.oxfordjournals.org/content/133/3/652.full
- Sarrouy, C.; Raffi, A.; Boineau, N. (1957-01-01). "[2 Cases of cerebellar hypoplasia in the same family]". Archives Françaises De Pédiatrie 14 (5): 449–460. ISSN 0003-9764. PMID 13445326.
- Wichman, A (1985). "Autosomal recessive congenital cerebellar hypoplasia.". Clin Genet. 1985 Apr;27(4):373-82. PMID 3995786.
- Mathews, KD (1989). "Autosomal recessive cerebellar hypoplasia". J Child Neurol. 1989 Jul;4(3):189-94. PMID 2768782.
- Bosemani, Thangamadhan; Orman, Gunes; Boltshauser, Eugen; Tekes, Aylin; Huisman, Thierry A. G. M.; Poretti, Andrea (2015-02-01). "Congenital abnormalities of the posterior fossa". Radiographics: A Review Publication of the Radiological Society of North America, Inc 35 (1): 200–220. doi:10.1148/rg.351140038. ISSN 1527-1323. PMID 25590398.
- Patel, Sandeep; Barkovich, A. James (2002-08-01). "Analysis and classification of cerebellar malformations". AJNR. American journal of neuroradiology 23 (7): 1074–1087. ISSN 0195-6108. PMID 12169461.
- "Cerebellar Hypoplasia Information Page: National Institute of Neurological Disorders and Stroke (NINDS)". www.ninds.nih.gov. Retrieved 2016-01-22.
- Sensory Learning (2009) Cerebellar Hypoplasia Sensory Learning.com
- Australian Capital Territory Cerebellar Hypoplasia Support Network Incorporated
- cerebellar_hypoplasia/cerebellar_hypoplasia.htm at NINDS
- Cerebellar hypoplasia at NIH's Office of Rare Diseases
- Cerebellar hypoplasia at Right Diagnosis
- Cerebellar Hypoplasia at Omim
- Living with Cerebellar Hypoplasia video