Genetic Testing of Han Chinese Population in Taiwan

Europe is not the only place where biobanks are creating opportunities for predictive genomics to help people. Predictive genomics relies on the combination of extensive, easily searched medical records with genomic data, and anywhere that has both of these things can combine them into a biobank and get started. The island of Taiwan presents just such an opportunity.

Taiwan Precision Medicine Initiative

Biobanks & Predictive Genomics

In this webinar, Dr. Pui-Yan Kwok of the Institute of Biomedical Sciences of the Academia Sinica in Taipei and the University of California in San Francisco, presents work undertaken as part of the Taiwan Precision Medicine Initiative. This initiative seeks to capitalize on the fact that Taiwan has most of the same factors working in its favor as Finland or Estonia from a predictive genomics standpoint: it has an ethnically homogenous population, universal health insurance, and an enviable electronic health record system.

Taiwan Precision Medicine SNP Array

The Taiwan Precision Medicine Initiative used reference genomes to create the Taiwan Precision Medicine SNP Array, a tool for collecting genetic information from large numbers of people that is less cumbersome than whole-genome sequencing but deep enough for predictive genomics. Up to 30% of Taiwan’s population lives in participating hospital districts, making this project potentially enormous even compared to other biobanking initiatives elsewhere in the world.

Risk Profiling SNPs Combined With Genetic Tests for Specific Diseases

The Taiwan Precision Medicine Initiative’s custom array includes 124,279 genetic tests for specific diseases and 578,776 risk-profiling SNPs. The hope is that combining known variants associated with heritable conditions, cancers, indications for adverse drug reactions, and more with more general risk profiling will lead to a body of data that, in addition to predicting heritable disease risk, can also include lifestyle risks in its calculations once enough people are included.

Preliminary Results

Preliminary results, taken from just over 100,000 people, show just how important this project is:

21% of test subjects have mutations in autosomal recessive disease genes, with some individual conditions’ genes being as high as 2.5%. This is important information for carrier screening.
5% have mutations for autosomal dominant traits, including nearly 1% with Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarct and Leukoencephalopathy (CADASIL), the most common single-gene disorder causing stroke. Interestingly, although more than 200 mutations of the NOTCH3 gene are known to cause CADASIL, 70% of the aforementioned 1% show the same mutation, R544C, which is also common in the nearby Chinese provinces of Fujian, Zhejiang, Shanghai, and Jiangsu as well as in South Korea. CADASIL-related strokes in the affected population are much rarer than this high percentage, but this mutation has subclinical effects that indicate that a screening regimen to encourage such individuals to lower their risk of stroke with lifestyle changes could be helpful.
1% of the test population carries cancer risk variants included in the assay. Directing these people to earlier and more frequent screening might lead to earlier intervention or even prevention.

Finding and Helping High-Risk Individuals

Fully implemented, the TPMI hopes to find high-risk individuals for dozens of conditions and direct them to earlier and more frequent screening, relevant lifestyle changes, and early or presymptomatic treatment for their conditions, leading to better outcomes for these vulnerable people and fewer cases of conditions caught too late or left to worsen untreated before detection. It provides a way to focus resources where they will do the most good and direct increased attention to people who benefit from it. As the quantity and quality of its data improves, it will become less of a polygenic risk score and more of an all-in-one personal health advisor.

Potential to Provide Predictive Genomics Insight for 1.5 Billion People

Taiwan’s biobanking project is particularly noteworthy because it is a rare example of one whose target population is not primarily or solely of European descent. This reality limits the applicability of data from the more famous biobanking projects in the United Kingdom, Finland, and Estonia and requires that Dr. Kwok’s team tailor their efforts accordingly. More than that, this project has the potential to provide predictive-genomics insight for the entire Han Chinese population worldwide, which comprises 1.5 billion people and 19% of all humans worldwide. One of the most noteworthy preliminary findings is that 87% of the test population has at least one variant that affects their response to at least one drug, which is partly due to drugs’ baselines mostly being calibrated on the largely European-descended populations used in drug trials. Some individual gene variants suggest that up to 80% of Han Chinese will have difficulty with “ordinary” doses of some drugs, such as warfarin. The TPMI hopes to develop a system similar to allergy alerts in medical records, flagging unusual drug reactions or dosing instructions based on a patient’s genetics and suggesting alternatives.

Watch Dr. Kwok’s presentation for more information about the Taiwan Precision Medicine Initiative.

Learn more: Predictive Genomics to Power the Future of Population & Personalized Health