Bilateral perisylvian polymicrogyria
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.
Age of Onset
Autosomal dominant ?A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease
Autosomal recessive ?Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype
X-linked dominant ?X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.
X-linked recessive ?Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder
Mitochondrial or multigenic ?Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.
Multigenic or multifactor ?Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.
Other Names (AKA)
Perisylvian syndrome; Polymicrogyria, bilateral perisylvian; Congenital bilateral perisylvian syndrome;
Congenital and Genetic Diseases; Nervous System Diseases
Bilateral perisylvian polymicrogyria (BPP) is a rare neurological disorder that affects the cerebral cortex (the outer surface of the brain). BPP is a subtype of a broader condition known as polymicrogyria. The cerebral cortex of the brain normally consists of several deep folds and grooves. In BPP, the grooves that develop during embryonic growth form improperly on both sides of the brain near the Sylvian fissure, resulting in an increased number of folds that are unusually small. Signs and symptoms typically become apparent at birth, infancy, or later during childhood, and may include partial paralysis of the face, tongue, jaw, and throat; problems with speech and swallowing; excessive drooling; and
- Partial paralysis of muscles on both sides of the face, tongue, jaw, and throat
- Sudden, involuntary spasms of facial muscles
- Excessive drooling
- Difficulty with sucking, chewing, and/or swallowing (
- Difficulty with speech (
spasticityof the limbs (spastic tetraplegia) Developmental delayor learning impairments
- Mild to severe
intellectual disability Contracturespresent from birth ( congenital)
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
|Bilateral perisylvian polymicrogyria||0032407|
|30%-79% of people have these symptoms|
|Delayed speech and language development||
Deficiency of speech development
Delayed language development
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
[ more ]
|EEG with parietal focal spikes||0012017|
|EEG with polyspike wave complexes||0002392|
|Global developmental delay||0001263|
Decreased muscle tone in infant
Mental retardation, nonspecific
[ more ]
|Perisylvian predominant thick cortex pachygyria||0020190|
|Specific learning disability||0001328|
|5%-29% of people have these symptoms|
|Abnormality of masticatory muscle||0410011|
|Cerebellar vermis hypoplasia||0001320|
Blockage of the rear opening of the nasal cavity
Obstruction of the rear opening of the nasal cavity
[ more ]
Lack of coordination of movement
|Ectopic posterior pituitary||0011755|
|EEG with frontal focal spikes||0012015|
[ more ]
|Focal sensory seizure||0011157|
Acid reflux disease
[ more ]
[ more ]
|Intrauterine growth retardation||
Prenatal growth deficiency
Prenatal growth retardation
[ more ]
Increased muscle tone of arm or leg
|Lower limb spasticity||0002061|
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference
[ more ]
Little lower jaw
Small lower jaw
[ more ]
Involuntary, rapid, rhythmic eye movements
Partial paralysis of legs
Tongue sticking out of mouth
[ more ]
|Percent of people who have these symptoms is not available through HPO|
|Atypical absence seizure||0007270|
|Bilateral tonic-clonic seizure||
Grand mal seizures
Abnormality of cognition
[ more ]
More grooves in brain
Single gene disorders that have been associated with BPP include:
- MPPH syndrome caused by a mutation in the AKT3, CCND2, or PIK3R2 genes
- Smith-Kingsmore syndrome caused by a mutation in the MTOR gene
- MCAP syndrome caused by mutations in the PIK3CA gene
- Lissencephaly caused by a mutation in the TUBA1A gene
- Weaver syndrome caused by a mutation in the EZH2 gene
- Magnetic resonance imaging (MRI) a diagnosis of polymicrogyria is usually made by
MRIbecause MRI typically can detect the small folds in the brain more effectively than other imagingtechniques.
- Electroencephalography (EEG) a test that measures electrical activity in the brain
- Computed tomography (CT) scanning
Genetic testingdifferent types of genetic tests may be performed to determine if there is a genetic cause for the BPP.
- The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
- Genetics Home Reference (GHR) contains information on Bilateral perisylvian polymicrogyria. This website is maintained by the National Library of Medicine.
- The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
- GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
- The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
- Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine.
- Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
- PubMed is a searchable database of medical literature and lists journal articles that discuss Bilateral perisylvian polymicrogyria. Click on the link to view a sample search on this topic.
- Congenital Bilateral Perisylvian Syndrome. NORD. 2015; https://rarediseases.org/rare-diseases/congenital-bilateral-perisylvian-syndrome/.
- Kilinc O, Ekinci G, Demirkol E & Agan K. Bilateral agenesis of arcuate fasciculus demonstrated by fiber tractography in congenital bilateral perisylvian syndrome. Brain Dev. March 2015; 37(3):352-355. https://www.ncbi.nlm.nih.gov/pubmed/24852949.
- Stutterd CA, Leventer RJ. Polymicrogyria: a common and heterogeneous malformation of cortical development. Am J Med Genet C Semin Med Genet. June, 2014; 166C(2):227-239. https://onlinelibrary.wiley.com/doi/full/10.1002/ajmg.c.31399.
- Stutterd CA, Dobyns WB, Jansen A, Mirzaa G, Leventer RJ. Polymicrogyria Overview. GeneReviews. August 16, 2018; https://www.ncbi.nlm.nih.gov/books/NBK1329/.
- Guerrini R, Marini C. Genetic malformations of cortical development. Exp Brain Res. August, 2006; 173(2):322-333. https://www.ncbi.nlm.nih.gov/pubmed/16724181.
- Clark M, Neville BG. Familial and genetic associations in Worster-Drought syndrome and perisylvian disorders. Am J Med Genet A. January 1, 2008; 146A(1):35-42. https://www.ncbi.nlm.nih.gov/pubmed/17994559.
- Guerrini R, Filippi T. Topical Review: Neuronal Migration Disorders, Genetics, and Epileptogenesis. J Child Neurol. April, 2005; 20(4):287-299. https://journals.sagepub.com/doi/abs/10.1177/08830738050200040401.
- Polymicrogyria, Bilateral Perisylvian, Autosomal Recessive; BPPR. Online Mendelian Inheritance in Man (OMIM). April 22, 2014; https://www.omim.org/entry/615752.