Researchers have discovered a novel genetic disease associated with vitamin B12 deficiency. Researchers have identified a gene that is vital to the transport of vitamin into the cells of the body.
This new discovery is expected to help doctors better diagnose this rare genetic disorder and open the door to new treatments.
Vitamin B12 is essential to human health but some people have inherited conditions that leave them unable to process vitamin B12. As a result they are prone to serious health problems, including developmental delay, psychosis, stroke and dementia.
"We found that a second transport protein was involved in the uptake of the vitamin into the cells, thus providing evidence of another cause of hereditary vitamin B12 deficiency," Dr. David Rosenblatt, one of the study's co-authors from McGill University, said.
"It is also the first description of a new genetic disease associated with how vitamin B12 is handled by the body," he said,
These results build on previous research by the same team from the RI MUHC and McGill University, with their colleagues in Switzerland, Germany and the United States.
In previous work, the researchers discovered that vitamin B12 enters our cells with help from of a specific transport protein. In this study, they were working independently with two patients showing symptoms of the cblF gene defect of vitamin B12 metabolism but without an actual defect in this gene.
Their work led to the discovery of a new gene, ABCD4, associated with the transport of B12 and responsible for a new disease called cblJ combined homocystinuria and methylmalonic aciduria (cblJ-Hcy-MMA).
Using next generation sequencing of the patients' genetic information, the scientists identified two mutations in the same ABCD4 gene, in both patients.
"We were also able to compensate for the genetic mutation by adding an intact ABCD4 protein to the patients' cells, thus allowing the vitamin to be properly integrated into the cells," Dr. Matthias Baumgartner, senior author of the study, said.
"This discovery will lead to the early diagnosis of this serious genetic disorder and has given us new paths to explore treatment options. It also helps explain how vitamin B12 functions in the body, even for those without the disorder," Dr. Rosenblatt added.
The study has been published in the journal Nature Genetics.