Genes that help build strong bones in Europeans or Australians may have a very different effect in people from Southeast Asia, say Australian and Vietnamese researchers in a new study.
Many genome-wide association studies have identified genes strongly associated with bone mineral density (BMD) in Caucasian populations. When 29 of the most influential of these genes were tested in the Vietnamese population, only 3 were found to be associated with BMD.
The impact of the 3 genes was found to be very modest, together explaining less than 3% of the BMD variation in the study participants.
The study also found that ‘genetic variants’1 have different magnitudes of influence in the populations, sometimes with opposite associations.
For example, 31% of the Caucasian population carries a variant of the SP7 gene, associated with low BMD. Only 17% of the Vietnamese population carries the same variant, and it is associated with high BMD.
Professor Tuan Nguyen from Sydney’s Garvan Institute of Medical Research, in collaboration with Dr Lan Ho-Pham, Co-Director of the Bone and Muscle Research Lab at the Ton Duc Thang University and Head of Rheumatology at People’s Hospital 115 in Ho Chi Minh City, randomly recruited 564 men and women from Ho Chi Minh City, aged over 18. Thirty-two single nucleotide polymorphisms (SNPs2) in 29 genes were genotyped and analysed in relation to BMD. The results of the study, the first of its kind in Southeast Asia, are reported in the international journal Bone, now online.
“We know that bone mineral density is stongly regulated by genes, and we suspect that environment modulates the effect of genes,” said Professor Tuan Nguyen.
“We take it for granted that soils in different regions have a different effect on plants and crops – for example a Hunter Valley Shiraz is very different from a Chilean Shiraz.
“A country is the ‘soil’ in which people grow, so we might expect to find the population differences highlighted in our study.
“A recent study in Korea echoed many of our findings in Vietnam, including the association of the SP7 variant with high BMD. This suggests there are similarities among the peoples of Southeast Asia in much the same way that there are similarities among Caucasians.”
There are likely to be dozens of genes associated with BMD in Southeast Asian populations, and the fact that only 3 have so far been identified represents an opportunity for further research. Professor Nguyen plans to undertake whole genome sequencing on a sample of people from this study in order to identify the genes that most closely associate with BMD in Vietnam.
1. The same gene can be coded in different ways in different people, manifesting as various physical qualities or ‘phenotypes’.
2. Single nucleotide polymorphisms (SNPs) represent a difference in one nucleotide (building block of DNA) that occur frequently within a population.
Science Communications Manager
Garvan Institute of Medical Research
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