Scientists from Seattle Children's Research Institute and the University of Washington, in collaboration with the Genomic Disorders Group Nijmegen in the Netherlands, have identified two new genes that cause Baraitser-Winter syndrome, a rare brain malformation that is characterized by droopy eyelids and intellectual disabilities.
"This new discovery brings the total number of genes identified with this type of brain defect to eight," said William Dobyns, MD, a geneticist at Seattle Children's Research Institute. Identification of the additional genes associated with the syndrome make it possible for researchers to learn more about brain development. The study, "De novo mutations in the actin genes ACTB and ACTG1 cause Baraitser-Winter syndrome," was published online February 26 in Nature Genetics.
The brain defect found in Baraitser-Winter syndrome is a smooth brain malformation or "lissencephaly," as whole or parts of the surface of the brain appear smooth in scans of patients with the disorder. Previous studies by Dr. Dobyns and other scientists identified six genes that cause the smooth brain malformation, accounting for approximately 80% of affected children. Physicians and researchers worldwide have identified to date approximately 20 individuals with Baraitser-Winter syndrome.