Researchers studying the genetic sequencing of schizophrenia have determined that identical twins are not genetically identical. The researchers sought to study the roots of the mental disorder, which is incapacitating for many individuals in the Portland area and throughout the country.
Portland residents who are unable to work because of a mental health condition such as schizophrenia may qualify for Social Security disability or Supplemental Security Income benefits. Schizophrenia and schizo-affective disorder are among the list of covered mental health disorders which also includes bipolar disorder and learning disabilities such as dyslexia.
One of the researchers who participated in the schizophrenia study is a molecular geneticist who looked at about 1 million markers of identical twins and their parents in twin sets where only a single twin had schizophrenia.
“We started with the belief that monozygotic (identical) twins are genetically identical, so if one member of identical twins has schizophrenia, then the risk for the other twin should be 100 percent, if it’s all due to genes,” the researcher said. “However, studies over the years have shown that the risk of the disease in both twins is only 50 percent.”
The researcher stressed that genes are not static and that cells divide and change as people develop. Cells may acquire or lose DNA, which is why about 12 percent of the DNA can vary across twins.
“So if schizophrenia is in the genes, then the difference in the genetic makeup of monozygotic twins, with only one disease twin, must have something to do with the disease,” he said.
Source: United Press International, “Genetics of schizophrenia studied,” 3/28/11