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When Identical Twins Are Different



Professor Aila Rissanen, University of Helsinki, Finland

Professor Aila Rissanen, University of Helsinki, Finland

This year’s prestigious Fredrich Wassermann Award of the European Association for the Study of Obesity presented at the 22nd European Congress on Obesity goes to Helsinki’s Aila Rissanen, Europe’s grande dame of obesity research.

I have personally known Aila for as lo as I have been involved in obesity and there is much in her work and approach to obesity that has stimulated my own thoughts on this issue.

In her acceptance address, Aila chose to focus on her work in BMI-discordant twins (among the many topics she has worked on) due to the remarkable insights into the “natre-nurture” discussion that this model offers.

Indeed, it is extremely rare to find genetically identical twins, who differ in body weight (demonstarting just how highly heritable body weight actually is). Thus, body weight in identical twins is remarkably homogeneous not only because of the heritability of weight per se but also due to heritability of weight gain.

Cining the work of her wildly successful trainee Kirsi Pietilainen, Aila described the efforts it took to identify just 30 obesity discordant (weight difference of >10 Kg) identical twins from well over 500 identical twin pairs.

These discordant twin pairs have now been extensively phenotyped with every imaginable laboratory test, measurement and tissue biopsies.

The most consistent difference between the discordant twins appears to be a greater level of physical activity in the leaner twin, which appears to precede the onset of weight gain.  In addition to voluntary physical exertion, there also appears to be a significant difference in fidgeting between the twins.

Compared to their co-twins, the obese twins had greater pro-inflammatory lipid profiles, lower antioxident activity and higher pro-coagulation markers. The reasons for these differences remains unclear.

Finally, Aila provided a brief overview of some of the exciting work that is now going on to further study the differences between these genetically identical but obesity disparate twins – metabolomics, lipidomics, epigenomics and even bacteriomics.

Although any of this has yet to translate to better obesity prevention or management, you never know where these fundamental insights into human biology may lead you.

For know, this is certainly a space I intend to watch.

@DrSharma
Prague, Czech Republic

2 Comments

  1. Love it, thanks for this Arya. Congratulations to both Aila and Kirsi. Aila certainly deserves this award. This chapter on genetics and environment is fascinating. Arya did they find any specific mutations of the genes, or epigentics that can explain why one twin fidgets or is more active. I believe that some degree of activity is willful, but to me, it is likely that wanting to be active is more genetic than not.

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    • Always so informative and on the pulse of what is happening in the world of obesity research. You change the world one post at a time!

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