One Malaysian Number Describes Nobody: Three Medicine Markers in the Cohort Browser

The question

When a researcher needs to know how common a genetic marker is in Malaysia, the easy answer is one national figure. But Malay, Chinese and Indian Malaysians can differ sharply at the same marker, and a single figure then describes none of them.

In the browser's ancestry build of 30 July 2026, 70,623 of the 740,809 markers compared differed by 20 percentage points or more in allele frequency between the three groups. The three markers below all affect how people respond to common medicines.

Three markers, three different patterns

Figures from the Malaysian Cohort Browser, ancestry build of 19 September 2026. Each figure shows how many people were measured for that marker.

• VKORC1 rs9923231. People with two copies of its T allele tend to need a lower dose of the blood thinner warfarin. Two copies, from the genotype counts the browser shows for each group: 79.7% of Chinese Malaysians (5,327 of 6,682), 53.3% of Malay Malaysians (1,005 of 1,885) and 8.5% of Indian Malaysians (50 of 586).
• CYP2C19 rs12248560, the *17 variant, which makes the CYP2C19 enzyme more active. That enzyme processes clopidogrel and some antidepressants and acid-reducing medicines. At least one copy: 33.3% of Indian Malaysians (189 of 567), 8.3% of Malay Malaysians (154 of 1,854) and 2.1% of Chinese Malaysians (140 of 6,603).
• ABCG2 rs2231142, which lowers the activity of a transporter that clears rosuvastatin and uric acid. At least one copy: 52.6% of Chinese Malaysians (3,529 of 6,708), 49.1% of Malay Malaysians (1,152 of 2,344) and 23.4% of Indian Malaysians (139 of 593).

What the pattern shows

The three markers do not follow one rule. For VKORC1, Malay Malaysians sit between Chinese and Indian Malaysians. For the other two markers, Malay Malaysians are much closer to Chinese Malaysians, and Indian Malaysians stand apart. A researcher cannot predict one group's figure from the others, or from a global database. It has to be measured.

What it means for research teams

Before a study on a medicine or a marker, a research team can look the marker up in the free Malaysian Cohort Browser. It shows the figure for each group, with the number of people behind it.

These figures come from genetic data only, not from medical records, and they are not medical advice. The groups are formed from genetic similarity, not from what participants said about their ethnicity, and their names are provisional. For a comparison across a whole panel of markers, contact us.

About Prima Nexus

Prima Nexus Sdn Bhd is a Malaysian research coordination group founded in 2014. It connects universities, research institutes and global technology partners, and runs eight scientific platforms under one roof: proteomics (including ELISA and Luminex multiplex immunoassays), genomics, flow cytometry, stem cell research, animal research, clinical trials, bioinformatics, and regulatory and grant support. Programmes it coordinates have supported more than 150 papers in peer-reviewed journals and research teams at more than 40 institutions across Malaysia. More about Prima Nexus.