bilateral frontoparietal polymicrogyria

Bilateral frontoparietal polymicrogyria (BFPP) is a congenital brain malformation that primarily affects the cerebral cortex and cerebellum, leading to a range of neurological and developmental challenges. The condition is caused by pathogenic variants in the ADGRG1 gene, which is important for normal neuronal migration during brain development. Signs typically become apparent in infancy or early childhood through low muscle tone, delayed milestones, and early seizure activity. Precise prevalence figures have not been established, but reports in the medical literature suggest it is very rare worldwide.

The defining feature of BFPP is an abnormal folding pattern of the cerebral cortex called polymicrogyria, most evident in the frontal and parietal lobes on magnetic resonance imaging. Early in life, many infants present with hypotonia that can make head control and sitting difficult. Developmental delay is common, and most children later show moderate to severe intellectual disability and language impairment, reflecting the condition’s strong cognitive and neurological impact. As children grow, additional neurological features often emerge. Non-progressive cerebellar ataxia leads to gait imbalance, truncal ataxia, and dysmetria, while pyramidal signs such as hypertonia may appear in the limbs. Epileptic seizures occur in the majority of affected individuals and can include generalized tonic-clonic, atonic, or absence seizures. Visual manifestations such as strabismus or deconjugate gaze are also reported. Less consistently, brain imaging can reveal ventriculomegaly, cortical dysplasia in regions beyond the frontoparietal areas, and hypoplasia of the pons or cerebellar vermis. Not all individuals experience all features, and severity varies considerably from one person to another.

BFPP results from inheriting two non-working copies of the ADGRG1 gene, which encodes a receptor that helps guide neurons to their proper positions during brain formation. Because the condition follows an autosomal recessive inheritance pattern, both parents of an affected child are usually healthy carriers of one altered copy each. When both parents carry the variant, each pregnancy has a 25 percent chance of resulting in an affected child, a 50 percent chance of producing a carrier, and a 25 percent chance of producing a child with no copies of the variant. BFPP may be more common when parents share a common ancestor because related parents are more likely to carry the same rare genetic change. Families are encouraged to seek genetic counseling to discuss carrier testing, family planning options, and implications for other relatives.

Currently, management focuses on supportive care and symptom management tailored to each individual. Antiseizure medications are selected based on seizure type, and physical, occupational, and speech therapies address motor coordination, language, and daily living skills. Because coordination difficulties and ocular misalignment can affect safety and learning, assistive devices and vision support services are often beneficial. Long-term care is best delivered through a multidisciplinary team that may include neurologists, physiatrists, physical therapists, speech-language pathologists, and educational specialists. Regular surveillance, including neurologic follow-up to adjust seizure control and monitoring of motor skills, helps identify emerging issues early. Families should discuss individualized rehabilitation goals and community resources with their care team, and genetic counseling is recommended for carrier testing and future family planning.

BFPP is a lifelong condition, but the course is not typically degenerative. Many children gain new motor and communication skills with therapy, although most continue to need support for coordination, cognition, and daily activities. Seizure control varies; some individuals achieve good control with medication, while others may have persistent episodes that affect quality of life. Outcomes described in medical literature continue to evolve as standards of care improve. Severity and long-term independence differ widely between individuals and depend on factors such as seizure burden, level of intellectual disability, and access to specialized rehabilitation services. Families often find it helpful to connect with neurologists familiar with polymicrogyria syndromes, participate in therapy programs, and engage with support networks that share practical strategies and emotional encouragement.