There is evidence for a significant overlap between genetic factors associated with risk of schizophrenia and genetic factors associated with age at first birth, according to new research by University of New England academic Dr S Hong Lee.
Dr Lee, from the UNE School of Environmental and Rural Science, and co-authors investigated the genetic relationship between schizophrenia and age at first birth in women using multiple independent genome-wide association study data sets.
According to Dr Lee this is the first study of its kind to explore a genetic relationship between schizophrenia and maternal age at first birth using a novel design consisting of independent unrelated samples based on genomic data involving almost 20,000 cases and 23,000 controls, and 12,000 community samples.
“We found that women with high genetic predisposition to schizophrenia tend have their first child at an early age or a later age compared with women in the general population,” Dr Lee said.
Parental age, a well-known risk factor for a range of mental health issue in children, is commonly believed to contribute to the risk of schizophrenia in children associated with early or delayed maternal age.
“We observed a U-shaped relationship between schizophrenia risk and age at first birth, consistent with the previously reported relationship between schizophrenia risk in offspring and maternal age when not adjusted for age of the father.” Dr Lee said.
“The findings are relevant as previously the risk of schizophrenia in children associated with older mothers was generally thought to be caused by the age of the father and possible mutations in germ cells (sperm). This explanation may now need to be revisited.”
The findings are published in a paper titled ‘Evidence for Genetic Overlap between Schizophrenia and Age at First Birth in Women’ in JAMA Psychiatry and can be accessed here: http://archpsyc.jamanetwork.com/article.aspx?doi=10.1001/jamapsychiatry.2016.0129