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基因與糖尿病 Genetics and Diabetes

Updated: Feb 23

人體每個細胞內都帶有遺傳基因,當中大約有二萬個是蛋白質編碼基因。這些基因均遺傳自父母,好像一幅設計藍圖,身體會根據這藍圖去生產蛋白質及控制人體結構功能。由於每人的基因存有差異,而正正卻因這些差異使我們有不同的外表特徵及體質。


解構基因與糖尿病

隨著科技的進步,人類一來以來不斷對這幅基因藍圖進行解碼,研究基因與糖尿病及其相關疾病的關連。研究證據顯示若直系親屬中(例如父母、兄弟姐妹)有人患上二型糖尿病,此人患上糖尿病的風險會比一般人高出最多3倍。研究還發現,每個人基因中的一些變異會對胰臟的發育、胰島素的產生和分泌,以及細胞對胰島素的敏感程度皆有影響。目前糖尿病基因研究已發現有超過100個基因變異與二型糖尿病有關,而糖尿病及其併發症是由多個基因變異所引致,但並不是所有的基因變異都會即時引發疾病,同時亦要配合其他糖尿病高危因素才會對健康產生影響。此外各國研究發現,不同種族與糖尿病相關基因亦有所差異,這些差異可能造成不同人群有不同的糖尿病病發率。例如在亞洲地區,尤其是中國糖尿病病人,有1/5人士是在40歲前發病,背後可能與種族的基因有關。


二型糖尿病起因

二型糖尿病的形成是綜合先天及後天因素的。若先天帶有多個高危基因,加上受到後天不良因素影響(如肥胖、吸煙等),再加上因為糖尿病的病徵不明顯而延遲診療,這些因素均會增加患上糖尿病的風險。相反,若本身帶有的高危基因數目不多,後天亦關注生活健康及時常留意自己的患病風險,這個人患上糖尿病的機會相對較低。雖然基因是無法改變的,但仍可透過改變形成糖尿病的後天因素(如體重)而降低風險。所以越早了解自己的身體狀況,就越能夠預防糖尿病。


真假一型糖尿病?

形成一型糖尿病主要是因為身體出現抗胰島細胞的反應,令自身免疫細胞破壞胰島細胞,最後因胰島素生產不足而最終導致血糖上升。研究同時發現多個基因與一型糖尿病有關聯,而這些基因的功能大多數與免疫系統有關。 另一種糖尿病,「年輕早發型糖尿病(Maturity Onset Diabetes of the Young,MODY)」,是一種由基因突變引起的單基因糖尿病。「年輕早發型糖尿病」與一型糖尿病相似,患者多數在年輕時發病,但亦因這方面兩者病徵較為相似,導致年輕早發型糖尿病病人常被誤診為一型糖尿病,並接受一型糖尿病的治療方法,導致治療效果未能達致理想。


了解精準治療

研究基因藍圖除了能分析不同的糖尿病類型之外,基因同時亦會反映藥物的效能及使用反應。以往要知道某種藥物對一個人的效用,往往需要長時間去觀察病人服藥後對整體病情的幫助及反應,然後根據情況再調整藥物的種類及劑量。但現在有基因資料作輔助,就可以準確地對症下藥,避免採用一些療效欠佳或未如理想的藥物,並作出個人化及精準的醫療方案。 相信在不久將來,醫護人員會普遍採用基因測試對高危人士作出患上糖尿病的風險預測,另一方面對糖尿病患者能夠作出正確的糖尿病分型,病況評估及採取精準的治療方針去減低發生併發症等的管理方案。如欲了解更多基因與糖尿病的資訊,請向專業醫務人員或醫生查詢。


Each cell in the human body contains genes and around 20,000 of these are protein-coding. These genes are inherited from the parents and are similar to a blueprint since the human body will produce proteins and control its structure and functions based on this “blueprint.” Since there are variations among individual’s genes, they enable us to be different in appearance and physique.


Understanding Genes and Diabetes

As technology advances, human has been trying to encode this genetic blueprint and studying genes and diabetes and their relationship with related diseases. Evidence from studies show that if an individual’s direct relatives (e.g., parents, siblings) have Type II diabetes, they are up to 3 times more likely than others to get it later in life. Studies also find that some genetic variations in individuals may affect the development of the pancreas, the generation and secretion of insulin, and the insulin sensitivity of cells.

Currently, diabetes genetic studies have discovered over 100 genetic variations associated with Type II diabetes, and diabetes and its complications are caused by multiple genetic changes. However, not all genetic variations will induce disease instantly, other risk factors of diabetes also contribute to our well-being. In addition, studies from foreign countries find that among different races, their diabetes-related genes are also different. These variations can lead to different incidence of diabetes in different groups of people. Using Asia as an example, ⅕ of Chinese diabetic patients see onset of the disease before 40 years of age and it is probably associated with race-related genes.

Cause of Type II Diabetes

Type II diabetes results from genetic and variable risk factors. If an individual naturally has multiple high-risk genes and is also affected by adverse environmental factors (e.g. obese, smoking, etc.), plus a delay in diagnosis and treatment because the diabetic symptoms are not obvious, these factors will all increase the risk of developing diabetes. On the contrary, if one has a limited number of high-risk genes and cares about one’s health as well as aware of the risks, then this individual has a relatively lower chance of developing diabetes. Although genes are irreversible, variable risk factors (such as weight) can be changed to reduce the risk. Therefore, the earlier you know about your physical conditions, the better you can prevent yourself from developing diabetes.

True or False Type I Diabetes?

Type I diabetes is mainly due to the immune system attacking islet cells which will result in increased blood sugar due to the insufficient production of insulin. Studies also find that multiple genes are associated with Type I diabetes and the functions of these genes are mostly related to the immune system. Another subtype of diabetes, namely “Maturity Onset Diabetes of the Young (MODY)”, is induced by a single gene mutation.

Similar to Type I diabetes, MODY patients usually show onset symptoms from a young age, and also due to the similarity between these two types, young “MODY” patients are often misdiagnosed with Type I diabetes and receive therapies for Type I diabetes, causing unsatisfactory treatment results.

Understanding Precision Medicine

The study of genetic blueprints not only can analyze different types of diabetes, the genome can also reflect the effectiveness of drugs and associated reactions. In the past when we wanted to know the effectiveness of a particular drug on an individual, it took quite some time to observe its benefits and reactions, and only then would the type of drug and dosage be adjusted according to the situation.

However, with the help of genetic information, precise decisions can be made to avoid using drugs with poor or undesirable results, and we can personalize a precise medical regimen. We believe in the near future, medical staff can use genetic tests as a common practice to perform risk prediction for people who are at a higher risk of developing diabetes.

On the other hand, diabetes patients can be diagnosed with the correct type and/or subtype, their conditions can be better assessed, and a management regimen of precise treatment can be applied to reduce complications. For further information about genetics and diabetes, please seek professional medical advice and consult a doctor.



#diabetes #gene #precisionmedicine


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