the loss of Y as a marker for their risk of various diseases.
Walsh also points to that possibility. Testing for the chromosome loss is already simple and inexpensive, he notes.
But screening is only useful if something can be done with that information. In the future, Walsh says, screening might identify men who could benefit from further testing for signs of fibrosis, or tissue scarring.
He notes that there are already some anti-fibrotic medications, used for scarring of the lungs. One question is whether men with Y loss would respond particularly well to those drugs.
What causes Y chromosome loss?
One of the remaining mysteries is what causes Y loss.
“There’s a lot of variability,” Walsh notes. “At the age of 60, some men show a lot of Y loss, and some show only a little.”
Studies have implicated smoking as one exposure that spurs greater Y loss, but not much else is known. “Some of it,” Walsh says, “may be the genes that you’re born with.”
And while women lack a Y chromosome, they can lose one of the X chromosomes in their blood cells as they age. It’s not as common as Y loss is in men, Walsh says, and so far, it has not been clearly linked to any disease risks.
Loss of Y could be one reason that women generally outlive men, according to Walsh. While part of that gap is explained by younger men dying of causes like accidents, it’s not the whole story, Walsh notes.
“It’s as if men biologically age faster,” he concludes.
For more information on the Y chromosome, click here.