What is Congenital bilateral perisylvian syndrome

Congenital bilateral perisylvian syndrome (CBPS) is a rare neurological disorder characterized by the malformation of the perisylvian regions of the brain, which leads to significant impairments in speech, swallowing, and motor control. The condition typically presents in early childhood with symptoms such as pseudobulbar palsy, epilepsy, and severe language deficits.

What are the primary symptoms and affected body systems?

Congenital bilateral perisylvian syndrome primarily affects the central nervous system, specifically the opercular regions of the cerebral cortex—the areas surrounding the sylvian fissure. Because this region controls the muscles used for facial expression, chewing, and speaking, individuals with Congenital bilateral perisylvian syndrome often face a constellation of specific challenges. Common clinical features include:

• Pseudobulbar palsy: Difficulty swallowing (dysphagia), excessive drooling, and impaired tongue movement.


• Speech impairments: Severe dysarthria or anarthria, making verbal communication difficult.


• Epilepsy: A significant portion of patients experience seizures, which may be focal or generalized.


• Cognitive and motor challenges: Variable degrees of intellectual disability and difficulties with fine motor coordination.

How is Congenital bilateral perisylvian syndrome diagnosed and classified?

Diagnosis of Congenital bilateral perisylvian syndrome is usually confirmed through neuroimaging, most commonly magnetic resonance imaging (MRI). The hallmark diagnostic feature is "polymicrogyria," a condition where the brain surface has an excessive number of small, abnormally formed folds in the perisylvian areas. Clinicians classify the condition based on the severity of these cortical malformations and the presence or absence of associated genetic syndromes. Currently, 45 individuals within the DiseaseMaps community have shared their experiences, providing a valuable pool of lived-experience data that helps families understand the wide spectrum of how Congenital bilateral perisylvian syndrome can manifest.

What causes this condition and who is affected?

The exact prevalence of Congenital bilateral perisylvian syndrome remains unknown, as it is an extremely rare disorder. It affects both males and females, and symptoms are typically noted at birth or in early infancy. The pathophysiology involves an interruption in the development of the cerebral cortex during the second trimester of pregnancy. While the exact cause is often idiopathic, research suggests that Congenital bilateral perisylvian syndrome can be linked to genetic mutations (such as in the SRPX2 or TUBB2A genes), viral infections during pregnancy, or localized vascular issues in the developing fetus. It is critical to differentiate this syndrome from other forms of cerebral palsy or primary speech-language disorders by the specific pattern of cortical malformation visible on brain imaging.

What differentiates this from other neurological conditions?

Unlike generalized cerebral palsy, which may involve broad motor deficits, Congenital bilateral perisylvian syndrome is defined by its anatomical specificity. The "bilateral" aspect is key; symptoms are symmetrical because the structural brain changes occur on both sides of the sylvian fissure. This creates a very specific profile of oromotor dysfunction that is distinct from conditions where brain injury is diffuse or affects different lobes of the brain.

Next steps

• Consult with a pediatric neurologist or a specialist in neurogenetics to discuss advanced imaging and genetic testing.


• Engage a multidisciplinary team including a speech-language pathologist (SLP) for augmentative and alternative communication (AAC) strategies and a feeding specialist.


• Connect with the 45 members of the DiseaseMaps community to share insights and support regarding daily management.


• Monitor for seizure activity closely and maintain regular follow-ups with an epileptologist if necessary.

Medical disclaimer: This information is for educational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Congenital bilateral perisylvian syndrome overview.


• Orphanet: Portal for rare diseases and orphan drugs (ORPHA:99933).


• OMIM (Online Mendelian Inheritance in Man): Perisylvian polymicrogyria, bilateral.


• PubMed/NCBI: Clinical literature on the genetic and structural basis of perisylvian cortical malformations.