My wife, a doctor, once asked me, “What was the name of that baseball player who died of Lou Gehrig’s disease?” I stared at her to try to determine if she was serious, then I finally said, “You mean Lou Gehrig?”

Needless to say, despite the man’s incredible achievements on the field, the ballplayer known as The Iron Horse—a career .340 batting average, 493 home runs, 1995 RBIs—is remembered for the disease that has come bear his name. Now, to add insult to brain injury, new research suggests Lou Gehrig may not have even had Lou Gehrig’s disease.

Researchers at the Boston University School of Medicine and the Department of Veterans Affairs report that they have the first pathological evidence that repetitive head trauma caused by collision in sports–such as bashing heads on a football field–is associated with motor neuron disease. Amyotrophic lateral sclerosis or ALS, also known as Lou Gehrig’s disease, is the most common form of motor neuron disease. It is a progressive neurodegenerative disease that attacks motor nerve cells in the brain and spinal cord, resulting in muscle weakness and atrophy. It almost always results in death.

The findings, which will be published in the September issue of the Journal of Neuropathology and Experimental Neurology, come from an examination 12 athletes’ brains and spinal cords donated to the Center for the Study of Traumatic Encephalopathy Brain Bank at Boston University School of Medicine. Three of the 12 athletes as well as an unidentified former military veteran and professional boxer, developed motor neuron disease late in their lives. The former football players were diagnosed clinically with ALS.

The researchers found that all 12 athletes showed neuropathological evidence of chronic traumatic encephalopathy, a progressive degenerative brain disease characterized by deposits of an abnormal form of a tau protein and believed to be caused by repetitive head trauma. Tau protein is abundant in neurons. In the three athletes with motor neuron disease, abnormal tau protein deposits were not only found throughout the brain, but also in the spinal cord.

The researchers also discovered that 10 of 12 chronic traumatic encephalopathy victims had a second abnormal protein, TDP-43, in their brains. Of those 10, only three had TDP-43 in the brain and the spinal cord, and those were the three athletes diagnosed with motor neuron disease, the researchers found. TDP-43 is also found in individuals with sporadic ALS although in the athletes with repetitive brain trauma, the TDP-43 pathology was more severe than found in sporadic ALS and was accompanied by extensive tau pathology. The brains and spinal cords of normal individuals show no TDP-43 or tau deposition, the researchers said.

The findings suggest that the motor neuron disease that affected the three athletes is similar to, but distinct from sporadic ALS and represents a disease never described previously in the medical literature. This new disease, referred to as chronic traumatic encephalomyopathy is likely caused by the repetitive head trauma experienced by athletes in contact sports, the researchers said.

The medical literature, it turns out, notes an association between head trauma and ALS. Athletes who participate in contact sports and veterans have been reported to have a higher incidence of the disease. One study of professional soccer players in Italy found that the rate of ALS was 6.5 times higher than in the general population. An increased incidence of ALS has also been reported in football players in the United States, including three players from the 1964 San Francisco 49ers who died from the disease. Based on the number of retired NFL players with ALS, the risk of the disease among this population is estimated to be at least 8 times higher than in the adult male population.

Veterans, too, face an elevated risk. The risk of ALS was 2.3 times higher than normal among veterans with a history of head injuries. Gulf War Veterans have a two-fold increased risk. In fact, since 2008, the U.S. Department of Veterans Affairs has considered ALS as a presumptively compensable illness for all veterans.

The researchers say the discovery of this new ALS-like disease suggests that one explanation for the greater risk of clinically diagnosed ALS in certain types of athletes and veterans may be the exposure to repetitive head trauma, including concussions, subconcussive blows and blast injuries. In fact, they say, the findings raise the question of whether head injuries may have contributed to Lou Gehrig’s motor neuron disease, and whether he also suffered from chronic traumatic encephalomyopathy.

Baseball is not exactly a contact sport, but it turns out before Gehrig donned his Yankee pinstripes, he played football at Columbia University. It turns out he suffered at least five documented concussions and was reported to have been knocked unconscious for five minutes after taking a pitch to the head while not wearing a helmet. Gehrig, who set a record that stood for 60 years by playing the most consecutive games, played the next day.

Gehrig’s association with ALS has no doubt raised the profile of an uncommon disease and attracted funding to research cures. Major League Baseball in 2009 teamed up with four leading ALS organizations to raise money and awareness to fight ALS. That’s nice, but maybe we can do a better job of paying homage to Lou Gehrig than naming a degenerative neurological disease after him, particularly one he may not have had. Will chronic traumatic encephalomyopathy come to be known as Lou Gehrig’s disease?

Gehrig told the fans of Yankee Stadium in a farewell speech that he considered himself the luckiest man on the face of the Earth. That’s hard for a man with ALS to say, but he may have been luckier than he realized.