What is (are) Koolen de Vries syndrome ?
Koolen de Vries syndrome, formerly known as 17q21.31 microdeletion syndrome, is a condition caused by a small deletion of genetic material from chromosome 17. The deletion occurs at a location designated as q21.31. People with 17q21.31 microdeletion syndrome may have developmental delay, intellectual disability, seizures, hypotonia. distinctive facial features, and vision problems. Some affected individuals have heart defects, kidney problems, and skeletal anomalies such as foot deformities. Typically their disposition is described as cheerful, sociable, and cooperative. The exact size of the deletion varies among affected individuals, but it contains at least six genes. This deletion affects one of the two copies of chromosome 17 in each cell. The signs and symptoms of 17q21.31 microdeletion syndrome are probably related to the loss of one or more genes in this region.