It’s surprisingly common for men to start losing entire chromosomes from blood cells as they age.
In the 1960s, doctors counting the number of chromosomes in human white blood cells noticed a strange phenomenon. Frequently—and more frequently with age—the cells would be missing the Y chromosome. Over time, it became clear this came with consequences. Studies have linked loss of the Y chromosome in blood to cancer, heart disease, and other disorders.
Now a new study—the largest yet of this phenomenon—estimates that 20 percent of 205,011 men in a large genetic database called the UK Biobank have lost Y chromosomes from some detectable proportion of their blood. By age 70, 43.6 percent of men had the same issue. It’s unclear exactly why, but the authors think these losses might be the most glaring sign of something else going wrong inside the bodies of these men: They are allowing mutations of all kinds to accumulate, and these other mutations could be the underlying links to cancer and heart disease.