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Do you fit these genes?

A potentially groundbreaking discovery has been made by researchers involving Ngati Porou Hauora and the universities of Otago and Auckland in identifying more information about a variant of a gene that only exists in Maori and Pacific peoples.

Studies by a nationwide team that includes a long-standing collaboration between Ngati Porou Hauora Charitable Trust and the universities of Otago and Auckland have identified the gene variant that associates with taller height in people who carry it.

The local programme of studies was initiated in 2006 through a discussion between the late Dr Paratene Ngata, a Ngati Porou Hauora GP, and Professor Tony Merriman from the University of Otago, who is also affiliated with the Maurice Wilkins Centre.

The discovery involves a gene variant named CREBRF that associates with lowered risk for type-2 diabetes in Maori and Pacific peoples. It is found in approximately 30 percent of people of Maori and Pacific ancestry but not to date in other ancestry groups around the world. Previous research from New Zealand researchers and others overseas shows that the same gene variant associates with increased body mass index (a measure of obesity), yet paradoxically with a lower risk of type-2 diabetes.

Internationally, this finding puts New Zealand and the Pacific on the map, drawing attention to genetic variants not found in other ancestry groups around the world.

The CREBRF gene variant was originally discovered in a Samoan population by American researchers, then by New Zealand researchers to also be present among Maori.

The new analysis, published in a paper today in the International Journal of Obesity, shows that the CREBRF variant is associated with an average height increase of 1.25cm for each copy of the gene a person has.

This could mean a total of 2.5cm height increase if both parents contribute the gene.

“1.25cm might not sound a lot but this is the biggest effect on height of any gene variant identified to date anywhere in the world,” said the paper’s lead author, Associate Professor Rinki Murphy (University of Auckland and Maurice Wilkins Centre for Molecular Bio-discovery).

“It highlights how differences in our genes can have an impact on our body shape and structure.”

Dr Murphy said that because it was so specific to Maori and Pacific peoples, the finding could lead to personally tailored medicine.

“The CREBRF variant’s associations with bigger bodies yet with protection from diabetes could contribute, among a lot of ongoing related research, to new ways to manage people’s metabolic risk or to develop management strategies that could help people with and without the variant.”

“It actually tells us a lot of new information about what controls diabetes overall. No one saw this coming, it’s a new part of physiology and biology that we’re learning about as we go,” said Professor Peter Shepherd (also of the University of Auckland and Maurice Wilkins Centre).

The researchers are now in the process of exploring the specific function of the gene variant that might contribute directly to controlling diabetes.

Ngati Porou Hauora deputy chair Huti Puketapu-Watson said Ngati Porou Hauora decided 13 years ago that partnering in this type of research is important, “to ensure our people are not left behind in benefiting from the new knowledge and enhanced services that improved understandings of both genetics and environmental factors will bring, including through new precision medicine approaches”.

She said the research was also helping to de-stigmatise being of larger body size and type 2 diabetes, conditions in which genetics play an important role.

“It empowers us, and helps to break the ‘one size fits all’ models underpinning health systems — for example, assumptions that interventions informed by research with populations of European ancestry will work well for Maori and Pacific peoples.”

Professor Merriman, also a co-author of the paper, recently discussed the key implications of this and other recent findings with participating East Coast communities.

In these annual “research updates” hui, he explained that the finding demonstrated how knowledge about a genetic variant could help people to understand why some of Maori and Pacific ancestry are healthy while also having a larger body size.

“Better understanding of such functions of genes like the CREBRF also adds evidential support to increasingly prevalent observations that body mass index may not accurately predict an individual’s risk of developing type-2 diabetes.”

Ngati Porou Hauora Charitable Trust Board chair Teepa Wawatai said the study was an unfolding story that aimed to “make into a firm connection” (between height and type-2 diabetes), and that it opened up looking at other genes and presented future opportunities with particular interventions that were “specific to our people”.

“This is an important partnership for us, developing our own Ngati Porou researchers, both at our Te Rangawairua o Paratene Ngata Research Centre here on the Coast and at the University of Otago, which is empowering our people to participate even more directly in this important work.”

Rose Kahaki from Ngati Porou Hauora said, “this study is by our people and for our people”.

The research programme has been expanding to include other Maori and Pacific groups nationwide, including through collaborations with the Maurice Wilkins Centre.

The Health Research Council has funded the University of Otago’s work with Ngati Porou Hauora, and is now also funding clinical studies in which Ngati Porou Hauora is participating with both universities to understand more about how the CREBRF and other gene variants might influence risks of developing prevalent chronic conditions like gout, diabetes, heart and kidney disease and also how gene variants may affect the effectiveness of current medications available to manage type-2 diabetes.

The overall aim of these studies is to deliver better health outcomes by understanding the biological bases of prevalent conditions, specifically for Maori and Pacific peoples.

Mr Wawatai said Ngati Porou Hauora began this journey “because we want our people to live longer and live better, and to understand what’s within them, and also what’s outside them”.

The data analysed in the journal article just published was gifted by over 1000 Maori or Pacific participants in New Zealand, a number that Dr Murphy said was a minimum requirement for a study of this kind.

And from Professor Shepherd: “It’s important that Maori are involved in research that affects their future.”

GENE DISCOVERY: Ngati Porou Hauora and The University of Otago have collaborated in a discovery of a variant of a gene that exists only in Maori and Pacific peoples. Researchers involved are back, Dr Jennie Harre Hindmarsh (left), Dr Rinki Murphy and Kim Ngarimu. Front, Matt Parvano (left), Rose Kahaki and Teepa Wawatai. Absent,Huti Puketapu-Watson and Professor Tony Merriman.Picture by Paul Rickard