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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
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.

Your Question

If a child is the only one affected with perisylvian syndrome in his family, can the inheritance of the syndrome be determined? Would perisylvian syndrome in a male child come from the mother or the father, or both? Is genetic testing for this syndrome available?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What causes bilateral perisylvian polymicrogyria?

The exact underlying cause of bilateral perisylvian polymicrogyria (BPP) is unknown. The signs and symptoms associated with the condition are thought 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 people affected by BPP, the cerebral cortex has an abnormally increased number of gyri that are unusually small. Scientists believe that these abnormalities occur when newly developed brain cells fail to migrate to their destined locations in the outer portion of the brain.[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.[1][2]
Last updated: 6/7/2015

Is bilateral perisylvian polymicrogyria inherited?

In most cases, bilateral perisylvian polymicrogyria (BPP) occurs sporadically in people with no family history of the condition.[1][2]

Rarely, more than one family member may be affected by BPP.[1][2] These cases may follow an autosomal dominant, autosomal recessive, or X-linked pattern of inheritance.[3]
Last updated: 6/7/2015

If a child is the only one affected with bilateral perisylvian polymicrogyria in his family, can the inheritance pattern of the syndrome be determined? Would this condition in a male child come from the mother or the father, or both?

It can be a challenge to determine if a particular case of bilateral perisylvian polymicrogyria is sporadic (e.g., due to a exposure or problem during pregnancy) versus genetic, especially if nothing in the family history or pregnancy history is indicative of a specific cause. In this case, knowing the gender of the child is not enough information to determine the probable cause of the condition.

If you or a family member has been diagnosed with this condition, you may find it helpful to speak with a genetics professional. To find a genetics clinic, we recommend that you contact your primary healthcare provider for a referral. The following online resources can also help you find a genetics professional in your community:
Last updated: 6/7/2015

Is genetic testing available for bilateral perisylvian polymicrogyria?

Genetic testing is not available for bilateral perisylvian polymicrogyria because the underlying genetic cause is unknown.
Last updated: 6/7/2015

References
Other Names for this Disease
  • CBPS
  • Congenital bilateral perisylvian syndrome
  • Perisylvian syndrome
  • Perisylvian syndrome, congenital bilateral
  • PMGX
Related Diseases
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.