It is becoming more evident that paternal age plays a role in genetic problems of offspring, similar to the widely acknowledged “biological clock” in women.
The latest science regarding the consequences of advanced paternal age will be reviewed during a critical discussion on Tuesday, titled Advanced Testing for Male Infertility: Age-specific Guidelines? The 20-minute discussion will begin at 8:20 a.m. during the Plenary I program in Hall A in the San Diego Convention Center. Dolores J. Lamb, PhD, HCLD, professor and Director of the Laboratory for Male Reproductive Research and Testing at the Baylor College of Medicine, will serve as critical discussant during the presentation.
The common perception among many urologists, Dr. Lamb said, is that a man’s age is largely irrelevant as long as he is making sperm. And even if age related risk is discussed, urologists are most likely to say the mid-40s is a reasonable cutoff to avoid problems, she added.
“Men have always thought they don’t have a biologic clock,” Dr. Lamb said. “It is becoming increasingly apparent that not only is the genetic integrity of their sperm declining as they age, but also their hormones, semen volume and things like that. Men do age, but in a different way than women do.”
However, there is still no consensus among researchers about what constitutes advanced paternal age. One of the most startling papers on the topic was published in Nature in 2012. It looked at mother-father-child trios among families in Iceland, where there has been a large amount of genetic sequencing in the population.
Starting with fathers who were just under the age of 30, there were about two mutations per year in the offspring as the age of the father increased. The study focused on autism and schizophrenia, but other studies have linked advanced paternal age with other genetic conditions.
Dr. Lamb said one of the first indications researchers discovered about advanced paternal age affecting offspring was the incidence of the Pfeiffer syndrome, a genetic disorder characterized by premature fusion of certain skull bones that prevents the skull from growing normally and affects the shape of the head and face. The syndrome also affects bones in the hands and feet.
The danger of a genetic defect from sperm is understandable, Dr. Lamb said, given that spermatogonia have the highest rate of proliferation of any cell type in the body. Each successive cell division represents an opportunity for a mutation to occur in the DNA sequence.
Advanced paternal age is an increasingly relevant consideration as couples are waiting longer to have children, Dr. Lamb noted. And as male fertility issues are increasingly discussed in the media, general practice urologists will likely be fielding more questions about the topic.
“Men are asking, ‘Should I be sperm banking? I am going to wait until I am 40,’” she said. “That is certainly not standard of care. There are places in the country where this is being widely done. It is a topic that comes up all the time now.”
Dr. Lamb said studies are focusing on more than just mutations. Researchers are also looking at meiotic and epigenetic effects.
“From a risk assessment point of view, yes, people are at higher risk,” Dr. Lamb said. “But if you are at higher risk for something rare, it is still rare. At least now people can make an intelligent, informed decision.”
Plenary I Preview
Advanced Testing for Male Infertility: Age-specific Guidelines?
Presenter: Dolores J. Lamb, PhD, HCLD
8:20 – 8:40 a.m. Tuesday
Hall A, San Diego Convention Center