Team led by Hong Kong-based scientist identifies genes linked to Alzheimer’s among Chinese population
Research is set to be extended to the city and will take at least eight years to complete, after which experts hope to acquire a better understanding of the disease
An international research team led by a Hong Kong-based neuroscientist has identified three genes that could indicate a higher risk of contracting Alzheimer’s disease among Chinese people.
The scientists said they hoped the discovery would lead to an earlier diagnosis for patients, with further research set to be extended to the city’s population.
The study, which investigated genetic links to Alzheimer’s disease in the Chinese population, is the first of its kind to be published. It was put out in February in Proceedings of the National Academy of Sciences, the official scientific journal of the National Academy of Sciences, a US-based NGO.
The team isolated two novel risk genes for Alzheimer’s and new variants of a gene that has been identified among Caucasians.
Nancy Ip Yuk-yu, leading scientist of the research and vice-president for research and graduate studies at the Hong Kong University of Science and Technology, said the project would soon extend to the city with the building of a patient database and tracking studies.
In collaboration with the Hospital Authority, Prince of Wales Hospital and Queen Elizabeth Hospital, the team has collected more than 800 gene samples from local patients and secured more than HK$50 million in early funding for the next phase of their research. The project is set to start in the first half of this year and would take at least eight years to complete.
“We hope the government can give us more support because this is going to be a large-scale and long-term research, which will need a lot more resources,” Ip said, adding that the team’s earlier published research had been supported by about HK$10 million from authorities in Hong Kong and mainland China.
Alzheimer’s has been linked to dementia in Hong Kong and around the world. In 2009, more than 100,000 people in the city were suffering from dementia, according to the Department of Health. A 2012 study by Chinese University estimated that by 2039, the number of affected people would increase to about 300,000 – 12 per cent of the total population aged above 65 – according to the government’s prediction.
Alzheimer’s patients lose their memories, speech and control over body movements because of lesions in their brains. It remains largely impossible for doctors to prevent, cure or delay the development of the disease because the causes are yet to be determined.
Previous research found a risk-factor gene called APOE based on studies on Caucasians.
Ip’s team, comprising scientists from Hong Kong, mainland China, Britain and the US, broke ground by applying the whole genome sequencing research method on more than 1,200 samples from Shanghai. The process involves determining complete DNA sequences.
All of the samples came from Han Chinese people aged between 55 and 90, who have no major diseases other than cognitive disorder and Alzheimer’s. A total of 489 in the pool were diagnosed with Alzheimer’s, while 260 had moderate cognitive disorder and the rest, or 473 individuals, were healthy.
It took Ip’s team four years to finish the whole genome sequencing for the group. Other than the APOE gene, researchers located two novel risk genes – GCH1 and KCNJ15.
The study also found that people with KCNJ15 might get Alzheimer’s two years earlier than average patients.
Ip said further studies were needed to determine how these genes participated in triggering the disease, as well as identifying their related syndromes.
“We have more than 4,000 samples from the mainland, based on which we will continue our work,” Ip said.
Further studies would also help the team develop and refine a risk scoring system for early assessment and diagnosis so that those at risk did not delay medical consultation until the onset of dementia, the scientists said.
Theoretically, the more risk genes a person has, the more likely the individual would have Alzheimer’s, according to Ip’s team. But more data and in-depth research on the disease’s mechanisms were necessary for better accuracy.
Dr Kin Mok, a team member from University College London, said existing assessment methods to locate the genes in question involved extracting cerebrospinal fluid, a costly procedure which was not well received by potential patients.