Two large scientific studies have found seven new genetic variants that make people put on weight, to add to two genes that were already linked to obesity in the general population.

    Both research teams – one led by deCode Genetics, an Icelandic biotechnology company, and the other an international academic consortium – published their findings on the 14 Dec in the journal Nature Genetics.

    The discoveries will be important for the global fight against obesity, one of the greatest public health problems of the 21st century.

    The most significant feature of the newly identified genes is that almost all of them are active in the brain, implying that they affect appetite rather than the biochemical processes of energy or fat metabolism.

    “This suggests that, as we work to develop better means of combating obesity, including using these discoveries as the first step in developing new drugs, we need to focus on the regulation of appetite at least as much as on the metabolic factors of how the body uses and stores energy,” said Kari Stefansson, chief executive of deCode.

    Samples from a total of more than 100,000 people were analysed in the two “genome-wide association studies”, which used the latest DNA-reading technology to associate genetic variations with body mass index.

    Body mass index is the most commonly used measure of obesity.

    Family and twin studies have shown that genetic factors account for 40-70 per cent of population variation in body mass index.

    Yet the first gene contributing to obesity in the general population, as opposed to people with rare metabolic disorders, was not discovered until 2007.

    Each of the newly identified genetic variations has only a modest effect: someone who carries all seven would typically be 1.5kg to 2kg heavier than an average adult.

    除了已經與普通人群肥胖癥掛鉤的兩種基因，兩項大型科學研究新發現了七種致人體重增加的基因變異。

    兩個研究小組——一個由冰島生物技術公司基因解碼(deCode Genetics)領導，另一個為國際學者聯盟——都于12月14日在《自然-遺傳學》雜志(Nature Genetics)上公布了他們的發現。

    這些發現將對全球抵御肥胖癥的戰斗具有重要意義。肥胖癥是21世紀最嚴重的公共健康問題之一。

    新發現的基因最顯著的特征是，它們幾乎全部活躍于大腦，這意味著它們影響著食欲，而非能量或脂肪新陳代謝的生化過程。

    基因解碼公司首席執行官凱里•斯蒂芬森(Kari Stefansson)表示：“這表明，在我們努力改進抵御肥胖癥的方法時，包括將這些發現作為研發新藥物的第一步，我們對調整食欲的關注度，至少要達到對人體消耗和儲存能量的新陳代謝因子的關注程度。”

    兩項“全基因組關聯研究”(genome-wide association studies)對來自10余萬人的樣本進行了分析，利用最新的DNA解讀技術，將基因突變與人體質量指數(body mass index)聯系起來。

    人體質量指數是采用最為廣泛的肥胖測量標準。

    對家庭和雙生子的研究表明，基因因素占人體質量指數群體變異的40%至70%。

    不過，導致普通人群肥胖（相對于罕見的新陳代謝紊亂人群）的基因直到2007年才被首次發現。

    每種新發現的基因突變都僅產生微弱的影響：攜帶全部七種基因的人通常會比普通成年人重1.5至2公斤。