15. January 2009
Cologne Scientists discover the Cause of rare Hereditary Disease
Transport Protein for Vitamin B12 has been identified
Professor Dr. Peter Nürnberg of the Cologne Center for Genomics (CCG) at the University Cologne and a team of international researchers have been successful in identifying the cause of the rare genetic disease CblF. The cause of this disease is a vitamin B12 deficiency (cobalamin-deficiency) caused by a genetic disorder. Vitamin B12 is important for cell division and haematopoiesis as well as for a functional nervous system. The body is not able to produce this vitamin itself and therefore takes it from meat and dairy products. What scientist have always known is that the vitamin is absorbed by small organelles called lysosomes on its way into the cell where it is then used. However, the manner in which these organelles entered the cells has now been discovered.
Working with Dr. Frank Rutsch from the paediatric clinic of the University Hospital of Münster, Prof. Dr. Peter Nürnberg established an international research team comprising paediatricians, geneticists and biologists from Germany France Canada and Switzerland. These scientists examined 12 patients suffering from the rare genetic disorder CblF and were able to identify an infinitesimal segment in the genetic information which was identical in almost all of the patients and which featured a defect in a certain gene. From this the team concluded that these patients, although from different countries, were in fact distantly related and shared a common ancestor going back eight or max. nine generations, who passed down the defective genetic information to them. People with one defective chromosome are completely healthy: it is only when two carriers of this defective chromosome have children that the disease occurs in the children of the carriers. In the case of those patients who do not have the same ancestors, other defects are found in the same gene.
The affected gene encoded the little known protein LMBD1 which scientists were able to identify in the lysosomes in human skin cells. Scientists were able to reactivate vitamin B12 transport and thus correct the gene defect by adding intact LMBD1 protein to the cells. The scientists then deduced from this that LMBD1 protein is responsible the transport of vitamin B12 from lysosomes into cells.
Following this success, the scientists will be concentrating on identifying exactly how vitamin B12 is transported through the lysosomes. The results of this research will be published on January 11, in the online edition of the journal Nature Genetics.
For Queries contact:
Prof. Dr. Peter Nürnberg
Cologne Center for Genomics (CCG)
of the University of Cologne
E-Mail: nuernberg(at)uni-koeln.de
Tel.: +49 (0)221 470-7821
Internet:
www.nature.com/ng/journal/vaop/ncurrent/full/ng.294.html
