A recently published paper called ‘Biallelic loss of human CTNNA2, encoding αN-catenin, leads to ARP2/3 complex overactivity and disordered cortical neuronal migration’ outlines new research into the genetic basis of pachygyria, a debilitating condition that affects children. You can click here to read a news release from Case Western Reserve University School of Medicine, which was a source used for this article, or find the original study here.
According to the NIH, pachygyria, also known as macrogyria, is a developmental condition that affects neurones (nerve cells) in the brain and nervous system. The condition can cause a range of symptoms, including seizures, developmental delay, weakened muscles, poor muscle control, and small head size, amongst others. The underlying process behind pachygyria is believed to be linked to abnormal migration of neurones. In typical brain growth, cells that will become neurones move to the surface of the brain and form layers. However, people who have abnormal migration may not develop enough cell layers, and gyri (ridges in brain wrinkles) may not develop properly, or at all.
Pachygyria can be caused by a range of genetic and environmental factors, such as infections during pregnancy, reduced oxygen flow to the brain during development, and alterations in several genes, says the NIH.
About the Study
An international team of genetics experts researched the genetic and developmental processes that cause pachygyria. The researchers found a link between pachygyria and an alteration in the CTNNA2 gene, which is involved in cell adhesion processes.
Three families affected by pachygyria took part in the research and underwent genetic sequencing. Based on the results of this, researchers found that the children with pachygyria showed alterations in both their copy of the CTNNA2 gene inherited from the mother and the copy inherited from the father. This meant that the children did not have a functional copy of CTNNA2.
CTNNA2 usually is involved in a process that prevents actin (a protein involved in neurone movement and cell shape) from binding to ARP2/3, a second protein. When CTNNA2 doesn’t function normally, these two proteins may be more likely to bind together, and this can disrupt neuronal processes such as migration, growth, and stability.
Future Research Possibilities
These findings could be used as the basis for further research. Some members of the team are planning to carry out more research that explores the effects of single-copy alterations of the CTNNA2 gene in people who have epilepsy, autism, and schizophrenia to better understand the effects of the gene.