Genetic Study of Lewy Body Dementia Supports Ties to Alzheimer’s, Parkinson’s
In an NIH-led study, scientists found that five genes may play a critical role in determining whether a person will develop Lewy body dementia (LBD), a devastating disorder that riddles the brain with clumps of abnormal protein deposits called Lewy bodies. These deposits are also a hallmark of Parkinson’s disease. The results, published in Nature Genetics, not only supported the disease’s ties to Parkinson’s but also suggested that people with LBD may share similar genetic profiles to those who have Alzheimer’s disease.
Lewy body dementia usually affects people over 65 years old. Early signs include hallucinations, mood swings and problems with thinking, movements and sleep. As the disease worsens, patients become severely disabled and may die within 8 years of diagnosis. There currently are no effective treatments.
“Patients [with LBD] often appear to suffer the worst of both Alzheimer’s and Parkinson’s diseases,” said NINDS investigator Dr. Sonja Scholz, senior author of the study. “Our results support the idea that this may be because Lewy body dementia is caused by a spectrum of problems that can be seen in both disorders.”
In the study, led by Scholz and NIA senior investigator Dr. Bryan Traynor, investigators compared the chromosomal DNA sequences of 2,981 LBD patients with those of 4,931 healthy, age-matched control participants. Samples were collected from participants of European ancestry at 44 sites across Europe and North America.
Initially, they found the sequences of five genes from LBD patients differed from those of the controls. It was the first time two of the genes, called BIN1 and TMEM175, had been implicated in the disease. These genes may also have ties to Alzheimer’s and Parkinson’s diseases. The other three genes, SNCA, APOE and GBA, had been implicated in previous studies, and thus, strengthened the importance of the genes in LBD.
Researchers replicated their initial results, finding differences in the same five genes in another study. They also found the genetic profiles of the patients in this study had higher chances of suffering from either Alzheimer’s or Parkinson’s disease than the control subjects.
“We hope these results will act as a blueprint,” said Scholz, “for understanding the disease and developing new treatments.”