Researchers at Mayo Clinic in Florida and the University of Florida have shed new light on the genetic and molecular underpinnings of amyotrophic lateral sclerosis (ALS), which may lead to improved diagnosis and treatment of the disease. The findings were presented Jan. 17 at a symposium co-hosted by the ALS Association and Mayo Clinic.
ALS, or Lou Gehrigâ€™s disease, is a devastating neurodegenerative disorder that affects motor neurons responsible for controlling the bodyâ€™s voluntary muscle activity. When the motor neurons are lost, the muscles involved in speaking, walking, breathing and swallowing become paralyzed. ALS is usually fatal within two to five years of diagnosis.
â€śI am very confident that in the near future we will have much better therapies and opportunities for patients living with the disease,â€ť says Lucie Bruijn, Ph.D., chief scientist for the ALS Association.
Her confidence stems from new investigations into the role genetic mutations and toxic proteins play in the disease as well as efforts to identify a biomarker that would allow clinicians to definitely diagnose ALS. While patients can currently undergo a simple blood test to learn whether they have high cholesterol or diabetes, no such test currently exists for ALS. As a result, the disease is underdiagnosed, says Dennis Dickson, M.D., who oversees all postmortem neuropathology studies as director of Mayo Clinicâ€™s Brain Bank.
Thanks to a groundbreaking study in 2011, scientists now know an abnormality in the gene C9ORF72 is the most common cause of familial and sporadic ALS and frontotemporal dementia (FTD). Rosa Rademakers, Ph.D., a neuroscientist at Mayo Clinic in Florida, led the study that helped explain why patients with ALS often develop symptoms associated with FTD and vice versa.
â€śWeâ€™re now trying to learn why some patients develop ALS while others develop FTD and why some patients are affected at a younger age than others,â€ť Dr. Rademakers says.
One key to unlocking the mystery may be to identify a link between abnormalities in the C9ORF72 gene and the major components of inclusions, or abnormal protein clumps, which are observed in the spinal cord and brain of ALS patients. Researchers at Mayo Clinic and the University of Florida are investigating how the aggregation of TAR DNA-binding protein-43 (TDP-43), copper zinc superoxide dismutase 1 (SOD1), and tau protein contribute to disease. Such understanding is an important step to identify where potential therapies should be targeted, says Tania Gendron, Ph.D., a neuroscientist at Mayo Clinic in Florida.
written by Caroline Stetler, Department of Neuroscience at Mayo Clinic in Florida