Bilateral Perisylvian Polymicrogyria (BPP)

In bilateral perisylvian polymicrogyria (BPP) the polimycrogyric malformation is limited to the cortical area surrounding the sylvian fissure. Typically, this will result in mild to moderate mental retardation, epilepsy, often of the symptomatic generalized type and difficulties with speech and oromotor function. Most cases are sporadic; however numerous families have been described, exhibiting heterogeneous inheritance patterns, including X-linked, autosomal recessive and autosomal dominant. Recently, a missense mutation in the Xq22 gene SRPX2 was found in an Australian 15-year-old male with rolandic seizures and BPP. The same mutation was also found in his unaffected mother and aunt, as well as in two maternal aunts with mild mental retardation but normal brain MRI. A second mutation in the SRPX2 gene was also identified in a 3-generation French family presenting with rolandic seizures, oral and speech dyspraxia and a variable degree of mental retardation. In cultured cells, both mutations were associated with altered patterns of intracellular processing, suggesting protein misfolding. SRPX2 is a secreted sushi-repeat containing protein, which carries a signal peptide and three consensus sushi-repeat motifs. Expression of SRPX2 was detected in most human tissues including the fetal and adult brain, in particular in neuron perikarya of the rolandic area.

We perform SRPX2 mutation analysis in patients with BPP in order established phenotype-genotype correlation. We also collect families in which BPP affects more than an individual.

If you have a child who you think may have this condition and you would like us to review the diagnosis or provide genetic testing please contact us at neuroscience@meyer.it.