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Genetic and Rare Diseases Information Center (GARD)

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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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Your Question

What is bilateral frontoparietal polymicrogyria? What are its symptoms? How is it different from bilateral perisylvian polymicrogyria in how it presents and what symptoms we see?

Our Answer

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What is bilateral frontoparietal polymicrogyria?

Bilateral frontoparietal polymicrogyria (BFPP) is an abnormality of the developing brain in which the brain develops too many folds (which are also unusually small). BFPP specifically affects the frontal and parietal lobes and occurs in both sides of the brain (bilateral). Signs and symptoms of BFPP typically include moderate to severe intellectual disability, motor developmental delay, seizures, cerebellar ataxia, strabismus, dysconjugate gaze (eyes that are not aligned) and other findings. Some cases of BFPP are caused by mutations in the GPR56 gene, and it is inherited in an autosomal recessive manner.[1]
Last updated: 8/24/2011

What are the signs and symptoms of bilateral frontoparietal polymicrogyria?

The most commonly reported signs and symptoms in individuals with bilateral frontoparietal polymicrogyria (BFPP) include moderate to severe intellectual disability; motor and cognitive developmental delay; seizures; cerebellar dysfunction; and dysconjugate gaze (eyes that are not aligned). Other findings that have been reported include increased muscle tone; mild truncal ataxia (decreased ability to perform smoothly coordinated voluntary movements); finger dysmetria (difficulty controlling speed, distance and/or power of movements); and strabismus.

In addition to polymicrogyria, brain MRI studies may show enlarged ventricles, reduced white matter volume (showing areas containing nerve fibers), patchy white matter signal changes, and underdevelopment of the cerebellum and brainstem.[1]
Last updated: 8/24/2011

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