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Bilateral perisylvian polymicrogyria


Other Names for this Disease
  • CBPS
  • Congenital bilateral perisylvian syndrome
  • Perisylvian syndrome
  • Perisylvian syndrome, congenital bilateral
  • PMGX
More Names
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Overview



What is bilateral perisylvian polymicrogyria?

What are the signs and symptoms of bilateral perisylvian polymicrogyria?

What causes bilateral perisylvian polymicrogyria?

Is genetic testing available for bilateral perisylvian polymicrogyria?


What is bilateral perisylvian polymicrogyria?

Bilateral perisylvian polymicrogyria (BPP) is a rare neurological disorder that may be apparent at birth, infancy, or later during childhood. It is characterized mainly by partial paralysis of muscles on both sides of the face, tongue, jaws, and throat; difficulties in speaking, chewing, and swallowing (dysphagia); and/or seizures (epilepsy). In most cases, mild to severe intellectual disability is also present. While the exact cause of BPP is not fully understood, this condition is thought to be due to improper development of the outer surface of the brain (cerebral cortex) during embryonic growth. In most cases, BPP appears to occur sporadically (non-inherited) for unknown reasons in a person with no family history of the disorder. However, there are reports of a few families in which more than one member has BPP. Environmental causes of the disorder can include exposure to cytomegalovirus (CMV) during pregnancy. Treatment usually focuses on the specific symptoms that are present in each individual and may include anticonvulsant drugs to help prevent, reduce, or control epilepsy associated with the condition.[1]
Last updated: 1/15/2014

What are the signs and symptoms of bilateral perisylvian polymicrogyria?

Bilateral perisylvian polymicrogyria (BPP) may be apparent at birth, in infancy, or later during childhood.The main features associated with BPP are partial paralysis of the muscles on both sides of the face (facial diplegia), seizures, and mild to severe intellectual disability. In addition to partial paralysis of the facial muscles, the jaws, tongue and throat may also be affected; this may cause difficulty chewing, swallowing or pronouncing certain words and sounds. Some individuals also have sudden, involuntary muscle spasms in the face. In addition to intellectual disability, children with BPP may have delays in motor development.

CT and MRI studies of the brain may confirm the typical malformations in affected individuals, such as perisylvian malformations and abnormalities of the brain's deep folds and grooves. An analysis of speech may also reveal characteristic patterns among individuals with the condition, such as problems pronouncing certain vowels or noises.[2]
Last updated: 8/25/2011

What causes bilateral perisylvian polymicrogyria?

The exact cause of bilateral perisylvian polymicrigyria (BPP) is not completely understood. The symptoms and findings associated with the condition are believed to be due to improper development of the outer surface of the brain (cerebral cortex) during embryonic growth. The cerebral cortex, which is responsible for conscious movement and thought, normally consists of several deep folds (gyri) and grooves (sulci). However, in cases of BPP, newly developed embryonic cells (neuroblasts) fail to migrate to their destined locations in the outer portion of the brain (neuronal dysmigration). As a result, the cerebral cortex does not develop the normal number of cellular layers, and the deep grooves that normally develop on the sides of both cerebral hemispheres may form improperly, resulting in an abnormally increased number of folds that are unusually small (hence the name, bilateral perisylvian polymicrogyria).[1]

The condition appears to occur randomly for unknown reasons (sporadically) in the absence of a family history, in most cases. However, a few families have been reported in which more than one member has been affected.[1]

Specific non-genetic causes of polymicrogyria have been recognized, including exposure to cytomegalovirus infection (CMV) during pregnancy. Polymicrogyria has also been associated with certain complications in twin pregnancies.[3]
Last updated: 5/6/2011

Is genetic testing available for bilateral perisylvian polymicrogyria?

The specific genetic cause of bilateral perisylvian polymicrogyria is unknown. However, GeneTests lists the names of laboratories that currently perform clinical genetic testing for polymicrogyria in general. To see a list fo these laboratories, click here.

GeneTests also lists the names of laboratories that are offering research testing for this condition. Research genetic tests may be used to find disease-causing genes, learn how genes work, or aid in the understanding of a genetic disorder. To see a list of the laboratories doing research testing on this condition, click here.
Last updated: 5/6/2011

References
  1. Perisylvian Syndrome, Congenital Bilateral. NORD. December 31, 2010; http://www.rarediseases.org/search/rdbdetail_abstract.html?disname=Perisylvian%20Syndrome%2C%20Congenital%20Bilateral. Accessed 5/6/2011.
  2. Perisylvian Syndrome, Congenital Bilateral. NORD. March 28, 2008; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/1067/viewAbstract. Accessed 8/25/2011.
  3. Cassandra L. Kniffin et al. POLYMICROGYRIA, BILATERAL PERISYLVIAN; BPP. OMIM. February 6, 2009; http://www.ncbi.nlm.nih.gov/omim/300388. Accessed 5/6/2011.