Glucose 6 Phosphate Dehydrogenase Deficiency (G6PDD)

Glucose-6-phosphate dehydrogenase (G6PD) is a very important enzyme for the healthy lifespan of red blood cells. A deficiency of this enzyme can lead to early breakdown of red blood cells, which causes hemolytic anemia. People affected by this condition do not notice any signs or symptoms until a medication or some other factors trigger them. The underlying cause or trigger factors need to be determined before proceeding with treatment options. 

G6PD deficiency is a genetic condition that passes down from generation to generation. It is inherited by a mutation in the X chromosome. Males have one X chromosome (XY) while females have two X chromosomes (XX). In males, this disease can occur if there is a mutation on the single X chromosome. In case of females, symptoms are dominant when there is a mutation on both of the X chromosomes, although a mild form of the disease may occur even if they have a single defective chromosome. For this reason, this disease is much more prevalent among males than females. Women with a single defective chromosome are often carriers and can pass this disease to their offspring.

Symptoms of G6PD can be triggered by certain medications such as antimalarials, sulfonamides, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs). It can also be triggered by infections, certain food substances such as fava beans or legumes, and chemicals in henna or hair dyes. 

Men are at the highest risk of getting affected by this disease. A single defective X chromosome can result in G6PD deficiency. A full-blown disease is rare in women, although mild symptoms may occur. This disease is most common among the population of Africa. Approximately 20% of the population is affected by this condition. Around 10% of African-American males in the United States have G6PD deficiency. It has also been noticed in people from the Middle East and South Asia. A positive family history of this condition is a major risk factor as it is passed in genes. Symptoms of G6PD can present at any age, but they are usually seen at a young age. 

People with G6PD deficiency often do not develop any symptoms until the disease is triggered by a medication, infection, or another factor. Once triggered, lack or absence of G6PD enzyme leads to hemolytic anemia. The symptoms that occur are present due to the early breakdown of red blood cells. These include jaundice, pale skin, dark-colored urine, fever, weakness, dizziness, confusion, difficulty performing a physical task, rapid heartbeat, shortness of breath, nausea, chills, heart murmur, and generalized fatigue. The liver or spleen may become enlarged in affected people because of the increased burden due to the rapid breakdown of red blood cells. Acute renal failure may occur in severe cases of G6PD deficiency. 

Family history is one of the most important indicators of this disease. Your doctor will ask if either one of your parents or grandparents had similar symptoms to those described above. History is followed by a physical examination in which signs of hemolytic anemia are noticed, such as jaundice, pale skin, rapid pulse, etc. Multiple blood tests are done, which include complete blood count (CBC), serum hemoglobin, and reticulocyte count. Urinalysis can also be done to notice the presence of hemoglobin in urine. A quantitative laboratory assay for G6PD enzyme activity can be done to measure the amount of enzyme present in the blood. The gold standard test for the diagnosis of G6PD deficiency is known as Beutler fluorescent spot test. It detects the activity of G6PD enzyme under ultraviolet light. A DNA test can also be done to confirm the presence of a mutated gene. 

There are a few other causes of hemolytic anemia, so it is important to differentiate G6PD deficiency from these diseases. Other causes include hereditary spherocytosis, sickle cell anemia, kernicterus, methemoglobinemia, bilirubin conjugation disorders, and unstable hemoglobin disorders. Differentiation can be done on the basis of diagnostic tests. 

Treatment of G6PD deficiency depends on the severity of the disease. If you were diagnosed at an early stage, precautionary tips are given to stay away from possible trigger factors. In case hemolytic anemia has been triggered, it is treated by avoiding the trigger factor in mild to moderate cases. For example, if the symptoms appeared after you took an aspirin, your doctor will recommend discontinuing that medicine and providing alternate options. In case of severe hemolytic anemia, it is difficult to manage this condition at home. You will need to be kept in a hospital where oxygen support will be given along with supportive therapy. Blood transfusion is also recommended in severe cases to replenish lost blood cells. You are monitored for a few days until your symptoms appear to get better. If you develop acute renal failure, you will be opted for dialysis. 

The prognosis of this disease is generally good in most cases. People with this disease are recommended to keep a list of possible trigger factors and avoid them to prevent the occurrence of symptoms. Even if symptoms occur, they fade away in a few days if the trigger factor is treated or discontinued. 

It is difficult to prevent this condition because it is a genetic disease. However, the activation of hemolytic anemia can be prevented if you avoid the trigger factors. These trigger factors can be certain medications, fava beans, some legumes, infections, etc. People with G6PD deficiency are also recommended to get hepatitis A and B vaccines to prevent these infections as they may worsen the disease.