The gene responsible for a brain disorder that leads to early deaths may be much more common than previously thought, according to a new study.

A team which includes researchers from Mayo Clinic in Florida has identified 14 different mutations in the gene CSF1R that lead to development of hereditary diffuse leukoencephalopathy with spheroids HDLS, a disorder of the brain’s white matter that leads to death between ages 40 and 60.

People who inherit the abnormal gene always develop HDLS, the authors said.

While a definite diagnosis of HDLS has required examination of brain tissue with a biopsy or autopsy, a genetic diagnosis will now be possible without that.

According to the study’s senior investigator, neurologist Zbigniew K. Wszolek, M.D., a significant number of people who tested positive for the abnormal gene in this study had been diagnosed with a wide range of other conditions.

Symptoms of HDLS vary widely, Wszolek said. Patients have been misdiagnosed has have schizophrenia, epilepsy, frontotemporal dementia, Parkinson’s disease, multiple sclerosis, and stroke, he said. That led to patients being treated with drugs offering toxic side effects, he said.

“Given this finding, we may soon have a blood test that can help doctors diagnose HDLS, and I predict we will find it is much more common than anyone could have imagined,” he says.

Lead author Rosa Rademakers, Ph.D., studied DNA samples from 14 families in which at least one member was diagnosed with HDLS and compared these with samples from more than 2,000 disease-free participants.

The authors explained that the “gene was ultimately found using a combination of traditional genetic linkage studies and recently developed state-of-the art sequencing methods.”

Most family members who were found to have HDLS gene mutations were not diagnosed with the disease, but with something else, thus emphasizing the notion that HDLS is an underdiagnosed disorder, said the authors.

“With no other disease have we found so many affected families so quickly,” Wszolek said. “That tells me this disease is not rare, but quite common.”