Hong Kong scientists found a genetic variant — highly prevalent among Chinese suffering from Alzheimer’s disease— that is linked with increased risk of the disease and which leads to rapid progression and severe brain volume loss.

The finding may contribute to further therapeutics development of the disease, with AD — the most common form of dementia — expected to affect around 50 million people by 2050 in China, up from approximately 10 million at present.

The genetic variant, identified as TREM2 H157Y, was found in about 1 in 200 Chinese patients with AD — five times higher than its prevalence in Europeans —after an in-depth clinical case study on six families with TREM2 H157Y variant carriers, the research team from Hong Kong University of Science and Technology (HKUST) announced on Thursday.

Nancy Ip Yuk-yu, president of HKUST and the research team leader, said that results noted that AD patients carrying the variant may develop a severe disease phase within three to five years. In comparison, other patients usually experienced the same level of severity six to eight years after being diagnosed.

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The clinical case study was conducted in collaboration with Timothy Kwok Chi-yui from the Prince of Wales Hospital, and the Chinese University of Hong Kong.

The research team noted that TREM2 H157Y variant carriers experienced a more rapid disease severity, and their MRI analysis shows more severe brain volume loss. Blood samples of variant carriers indicated more severe AD pathological changes.

Kwok noted that the study found that many family members of the variant carriers also showed early stage dementia symptoms.

The longitudinal study will further conduct follow-up studies in patients with AD carrying the TREM2 H157Y variant.

The team noted genetic factors account for 60 to 80 percent of the risk for late-onset AD. Currently, most AD genetic studies are conducted on Europeans. 

To address this, the Hong Kong Center for Neurodegenerative Diseases (HKCeND) — which was established under the government-funded InnoHK initiative — launched its biobank for AD research. Led by HKUST and in collaboration with hospitals in Hong Kong, this is one of the most comprehensive biobanks — containing over 6,000 sample numbers as well as clinical and multi-omics data — for Chinese AD patients.

The biobank collects and consolidates comprehensive clinical, neuroimaging, and multi-omics data from individuals of ethnic Chinese origin, and serves as a critical resource for investigating Chinese-enriched genetic factors.

Ip, who is also director of the HKCeND, noted that this inaugural study proved that TREM2 H157Y is associated with more severe AD pathology and neurodegeneration, and its findings can help formulate personalized patient management strategies and targeted therapeutics.

Contact the writer: atlasshao@chinadailyhk.com