Paternal Age Explains between 1/4 and 1/3 of all Schizophrenia

Dr. Dolores Malaspina interviewed by Dr. Norman Sussman


"The most irrefutable finding is our demonstration that a father’s age is a major risk factor for schizophrenia. We were the first group to show that schizophrenia is linearly related to paternal age and that the risk is tripled for the offspring of the oldest groups of fathers.7 This finding has been born out in every single cohort study that has looked at paternal age and the risk for schizophrenia. The only other finding that has been as consistently replicated in schizophrenia research is that there is an increased risk associated with a family history of schizophrenia. Since only 10% to 15% of schizophrenia cases have a family history, family history does not explain much of the population risk for schizophrenia. However, we think that approximately one third or one quarter of all schizophrenia cases may be attributable to paternal age. Paternal age is the major source of de novo genetic diseases in the human population, which was first described by Penrose8 in the 1950s. He hypothesized that this was due to copy errors that arose in the male germ line over the many cycles of sperm cell replications. These mutations accumulate as paternal age advances. After the Penrose report, medical researchers identified scores of sporadic diseases in the offspring of older fathers, suggesting that these could occur from gene mutations. Particular attention was paid to conditions in last-born children. In the 1960s, an excess of schizophrenia in last-born children was also reported."

http://www.schizophreniaforum.org/for/curr/Malaspina/default.asp




Paternal age at conception is a robust risk factor for schizophrenia. Possible mechanisms include de novo point mutations or defective epigenetic regulation of paternal genes. The predisposing genetic events appear to occur probabilistically (stochastically) in proportion to advancing paternal age, but might also be induced by toxic exposures, nutritional deficiencies, suboptimal DNA repair enzymes, or other factors that influence the

fidelity of genetic information in the constantly replicating male germ line. We propose that de novo genetic alterations in the paternal germ line cause an independent and common variant of schizophrenia.
genetic events appear to occur probabilistically (stochastically) in proportion to advancing paternal age, but might also be induced by toxic exposures, nutritional deficiencies, suboptimal DNA repair enzymes, or other factors that influence the

fidelity of genetic information in the constantly replicating male germ line. We propose that de novo genetic alterations in the paternal germ line cause an independent and common variant of schizophrenia.