What is G6PD deficiency?

Glucose 6-phosphate dehydrogenase (G6PD) deficiency is an enzyme deficiency of the red blood cells. G6PD deficiency leads to an abnormal rupture (breakage) of the red blood cells called hemolytic anemia (abnormally low red blood cell count).

What is the cause of G6PD deficiency?

The abnormal gene responsible for this inherited enzyme deficiency is located on the X-chromosome. Therefore, the illnesses associated with G6PD deficiency occur more frequently in males than females, since males only have one X-chromosome. There are different degress of G6PD deficiency, which vary according to the magnitude of the missing enzyme.
Usually, the hemolytic anemia occurs after exposure to certain compounds with oxidant properties, including drugs such as malaria medications, sulfonamides, antiitching drugs, dapsone, and others. Compounds with the property of inducing hemolysis in G6PD deficient persons are also found in the fava bean. This condition, known as favism, occurs within a day of ingestion of the fava bean. Favism can cause fever, back pain, headache, nause, and chills.

Can they donate Blood ?

G6PD deficiency is a genetic blood disorder. It is an inherited condition that affects the body’s red blood cells.
The great majority of people with G6PD deficiency are healthy and do not experience any symptoms clinically. As such, they are still allowed to make blood donations. However we usually would advise donors with G6PD deficiency to donate plasma or platelets via apheresis technique instead of whole blood. RBC donations are not recommended as their bone marrow is already working hard to compensate for their condition and we do not want to further exhaust their marrow. The red blood cells of those with G6PD deficiency are also more fragile. These red blood cells have a shorter lifespan and hence would not be suitable for transfusion to anaemic patients.

SEGI College Support Call to save life

During the just concluded 147th Blood Donation Campaign held on last Sunday, we welcome the students from SEGI College to respond to our call to save life. There were more than 30 of them, which I was told will be the future tour guides to boost our Penang tourism. As Georgetown has been listed as World Heritage, we certainly need more of these young and energetic people.

在刚结束的147期献血运动中，我们得到槟城SEGI学院的响应。这些就读导游课程的学生显示了他们勇敢和有爱心的一面，为这社会付出了一包包宝贵的血液。一行人在老师的带领下，完成了这项壮举。
乔治市已经被列入了世界古迹，正是须要这班生力军来推动槟州旅游业的时候。就看他们了！

什么是“Ｇ６ＰＤ缺乏症”？

这是蚕豆。有些人却不可以吃，还有它和捐血有什么关系呢？

Glucose 6-phosphate dehydrogenase (G6PD) deficiency

(缺乏六磷酸葡萄糖脱氢或简称酵素缺乏〕

Ｇ６ＰＤ缺乏症俗稱蚕豆病,是一种遗传性代谢缺陷，为Ｘ伴性不完全显性遗传，男性发病多于女性。G6PD的作用主要是維持紅血球的穩定，減少紅血球受侵襲時被破壞的一種酵素，其作用相等於一個國家的軍隊：閒時作用有限，但國家安全受威脅時則會發揮極大的保護作用。

由于Ｇ６ＰＤ缺乏症变异型很多，临床表现差异极大，轻型得可无任何症状，重型者可表现为先天性非球形红细胞溶血性贫血，一般多表现为服用某些药物、蚕豆或在感染后诱发急性溶血，重得可危及生命。

患者是可以将此病传给下一代的，规律是：父亲患病，可以传给女儿，不传给儿子；母亲患病，可以传给约半数的女儿和儿子。一般女性G6PD缺乏程度较轻，而男性较易发生溶血，还应注意的是：父母有这种酶缺乏时，婴儿出生时应留脐血检查，如不及时发现，并采取预防措施，婴儿很可能产生新生儿黄疸，造成终生智力低下。因此，进行产前诊断、治疗和新生儿疾病筛查及为重要。

除了忌吃蚕豆，亦切忌服用西藥如亞士匹靈，維他命K，中藥如川蓮，麻黃等。另一方面，患者最好避免經常接近含臭丸或樟腦氣味之物件/場所。

Ｇ６ＰＤ缺乏症的发病机制中涉及到一个重要的还原性物质 NADPH。G6PD缺乏者因不能产生足够的NADPH，故服用氧化性药物或蚕豆之后，产生过多的过氧化氢不能及时被还原，造成红细胞破坏而致急性溶血， 典型的是伯氨喹啉，多数解热镇痛消炎药也有氧化性。

誘使G6PD缺乏者發病之因素
1.嗅覺、觸覺因素:─→特別是臭丸、樟腦、冬青油、萬金油和顏料等。
2.食物：─→G6PD缺乏症也稱為「蚕豆病」，故名思義，蚕豆便是一主要的病發誘因，尤以新鮮蚕豆為甚。在農村，吸入蚕豆收成季節的花粉，亦曾會影響此病發生。
3.中藥:─→包括牛黃、川蓮、臘梅花及珍珠末、金銀花、熊膽等，個別項目應請教醫生。
4.西藥:─→西藥中也有很多會令酵素溶解而缺乏的，種類過百難以盡錄，應個別請教醫生，最常見的包括阿斯匹靈（水楊酸），這包括口服及塞肛、退燒的亞士匹靈、抗瘧藥、氯霉素、水溶維生素K3、磺胺等。
5.其他因素:─→包括新生期、感染、缺氧、腦出血、糖尿等亦會令G6PD缺乏症病發。一般上有Ｇ６ＰＤ缺乏症者都须要戴说明手鍊或頸鍊方便辨认.

患者可以捐血吗 ?

对于这点,议论纷纷,有人说可以,也有人说不可以。我请教了本地的血库单位, 答案是可以，但不被鼓励。对患者本身，会加重骨髓造血的负担，而捐出的血也可能会使接受者有不良反应。