Genetic risk factor associated with erectile dysfunction
For the first time, researchers have identified a genetic variant that increases the risk of erectile dysfunction (ED); the genetic variant is near a gene called SIM1 and may affect this gene’s activity. ED is a condition in which one is unable to get or keep an erection firm enough for satisfactory sexual intercourse. Symptoms of ED include being able to get an erection sometimes, but not every time; being able to get an erection but not having it last long enough for sexual intercourse; and being unable to get an erection at any time. Several different diseases and conditions can lead to ED including type 2 diabetes, heart and blood vessel disease, and chronic kidney disease, among others. Although men are more likely to develop ED as they age, aging does not cause ED. A twin study of middle-aged males reported that about one-third of ED risk is heritable—meaning that there is a genetic component(s), but specific genetic variants had not been identified.
Investigators recently undertook a genome-wide association (GWA) study of erectile dysfunction in a racially diverse cohort of 36,649 men. GWA studies can be used to search for rare or common susceptibility genes in large groups of individuals. Of the people studied, 14,215 men had reported ED symptoms, and these individuals were more likely to be older, have a slightly higher body mass index (a measure of weight relative to height), have diabetes, be smokers or former smokers, have a clinical diagnosis of ED, and have filled a prescription to treat ED, compared to the control population of 22,434 men. The researchers found that DNA sequence variations at a position in the genome (i.e., genetic locus) near the SIM1 gene are significantly associated with an approximate 26 percent increased risk of ED. The increased risk is independent of known risk factors such as higher body mass index. The DNA sequence variations were verified in a second cohort of 222,358 men. The researchers further showed a biological role for the implicated genetic locus. The locus resides within an “enhancer” element; enhancers are short DNA sequences that control the extent to which a gene is turned on or off. The researchers found that the variants they identified within the enhancer alter its ability to control the activity of the SIM1 gene.
This study reveals a previously unknown mechanism associated with ED, and lays the foundation for efforts to develop approaches targeting SIM1 to restore erection function and, thus, help men achieve a healthy sex life.
Jorgenson E, Matharu N2, Palmer MR,…Van Den Eeden SK. Genetic variation in the SIM1 locus is associated with erectile dysfunction. Proc Natl Acad Sci USA 115: 11018-11023, 2018.