Scientists suggests that the age of onset for Alzheimer's disease is influenced by the HLA-A2 gene or a neighboring gene on chromosome 6 that is closely linked to HLA-A2.
In the 207 Alzheimer's disease patients who were studied, those who had the HLA-A2 gene developed Alzheimer's disease at a younger age than those who did not carry the gene.
HLA-A2 is the second gene found to be associated with the common forms of Alzheimer's disease.
The other susceptibility gene, apolipoprotein E (APOE), is also associated with the age of onset of Alzheimer's disease.
Study suggests that the two susceptibility genes HLA-A2 and APOE together account for a decade variation in the age of onset.
The study included two patient populations: one with 111 patients and the other with 96 patients.
The second group was used as a confirmatory data set to validate the findings.
The next step is to pinpoint and isolate the culprit gene precisely as either HLA-A2 or another gene in the vicinity.
Once the gene is in hand, scientists can figure out what it does and how it modulates the onset of Alzheimer's disease.
By understanding the mechanism of action of these genes, scientists hope to devise intervention strategies to delay the onset of the disease.
But it is obvious that Alzheimer's disease most likely involves the interaction of many genes and that if HLA-A2 plays a role, it is not an exclusive one.