Clinical Significance of Glucose-6-Phosphate Dehydrogenase Deficiency

Abstract

Glucose-6-phosphate dehydrogenase deficiency is a genetic disorder passed down the lineage and is associated with enzymatic defects that lead to premature destruction of the red blood cells during Haematopoiesis. This damage, termed as hemolytic, leads to the low supply of blood and oxygen to the tissues and other body systems since the red blood cells cannot function properly or their quantities is too small leading to hemolytic anemia. This condition manifests itself in many ways, thereby understanding the clinical significance associated with it could help patients and other caregivers save a life. These guide the need to undertake a systematic review of the clinical relevance of Glucose-6-phosphate dehydrogenase deficiency and its pathophysiology, and this could provide recent development made in understanding the disease and its management with the aim to improve care and better management by physicians. The study was accomplished through a systematic review of the peer-reviewed articles from the Science Direct, PubMed, and Scopus databases. Articles were selected using search terms “clinical significance of G6pd Deficiency” and limited to those published within the last six years. Findings show that patients with alleles are likely to experience episodes of hemolytic anemia when exposed to pharmacogenetics and foods with condition ranging from severe to mild. The G6PD and levels of enzyme deficiency determine the severity. Foods like fava beans or their pollens, malaria and, and chemical agents act as oxidative stressors and thereby predisposing patients with hemolytic anemia. Low dosages of antimalarials, appropriate testing could improve patient outcomes.

Keywords: G6PD deficiency, risk factors, pharmacogenetics, testing, management.

Clinical Significance of Glucose-6-Phosphate Dehydrogenase Deficiency

Evaluating the clinical significance of glucose-6-phosphate dehydrogenase deficiency provides existing and emerging approaches that could be adopted for an improved patient outcome. Patients with glucose-6-phosphate dehydrogenase deficiency could be exposed to life-threatening conditions because clinicians are likely to overlook a comprehensive assessment when administering medications for other conditions whose drugs could generate adverse effects on patients with G6PD deficiency. Several diseases and infections act as predisposing factors that potentiate the risks for the G6PD deficiency. For instance, reports indicate that some anti-malaria drugs and some food items may induce the breakdown of red blood cells and this could worsen the situation if patients with Glucose-6-phosphate dehydrogenase deficiency. Interestingly, the occurrence of G6PD deficiency is more prevalent in endemic malaria regions, which increases the risks for such patients. Clinicians need an evidence-based approach that could help save patients and improve the strategies for their outcome. Besides, lack of an appropriate diagnostic plan for the G6DP deficiency and poor handling of sample could make it difficult to manage the condition safely and efficiently. Reviewing existing literature on the therapeutics reported to have adverse effects on patients with G6DP deficiency and using appropriate testing could provide guidelines for recommending appropriate management strategies for guiding the practitioners when dealing with cases of G6DP deficiency. Therefore, the review focuses on a systematic evaluation of the information relating to pharmacogenetics that could complicate the management of G6PD deficiency and evaluating the testing strategies for managing G6PD deficiency. This information is necessary to clinicians for it provides a roadmap for safe management of the condition based on clinical evidence. Besides, the finding could act as the guidelines for policy formulation when planning to roll out clinical trials in areas with high prevalence of G6PD deficiency.

Methods

The paper presents a systematic review, which involved sourcing for relevant articles from journals indexed in Science Direct, PubMed, or Scopus and using information that relates to the research search terms. These databases provide credible materials owing to the nature of review manuscripts undergo before acceptance for publications. Therefore, it was assumed that articles listed in these databases have undergone efficient peer review process and provide relevant information for this work. These items were selected based on the predetermined criterion, which included using key search words such as “Clinical Significance of G6PD Deficiency Pathophysiology.” Others terms used for the selection of appropriate papers included “G6pd enzyme deficiency.” Besides, the search was limited to include evidenced-based studies from clinical trials, case studies, or reviews of similar articles. Finally, the selection was based on previous studies reported within the last five years, with most recent ones given priority to ensure that the paper provides the latest information that could provide evidence for consideration.

Review of Literature

Pharmacogenetics as a Predisposing Factor

G6PD is an enzyme within the pentose phosphate pathway that produces NADPH, which provides cell protection against oxidative damages. The red blood cells lack mitochondria, nucleus and other organelles making the pentose pathway the single biochemical pathway involved in the reducing capacity (Luzzatto & Seneca 2013). Luzzatto and Seneca (2013) argued that pharmacogenetics has clinical implications for patients with G6PD. The primary challenge is that most clinicians may not have a picture of the entire health condition for each patient, which predisposes those with G6PD deficiency to potentially life-threatening conditions when exposed to some drugs that induces red blood cell destruction. According to Carter et al. (2011), G6PD deficiency is common in patients with malaria. The study terminated clinical trials on G6PD deficiency patients enrolled in Chlorproguanil-dapsone-artesunate treatment because of the increased risks associated with the hemolysis in such patients compared to the G6PD normal patients. The treatment with 8-aminoquinolines, which targets malaria, will remain the main problem to patients with G6PD deficiency. Interestingly, the study found that G6PD genotypes did not have the independent effect on malaria parasitemia, temperature, or baseline hemoglobin (Carter et al., 2011). The primary outcome of the study was the need for G6PD phenotyping and genotyping before using anti-malaria drugs to lower the risks to patients with G6PD deficiency.

Complications of Management

According to Najib et al. (2013), G6PD deficiency is a risk factor for the indirect occurrence of severe neonatal hyperbilirubinemia, and this could be contributing to the increasing cases of neonatal readmission. The risk factors were severe among the male, which subscribes to the prevalence of G6PD deficiency in most populations. G6PD deficiency resembles severe hyperbilirubinemia since both are based on family history. Although study associated G6PD deficiency as a risk factor for severe hyperbilirubinemia, their approach was limited and could not give any clinical relevance. However, it broadens our understanding of G6PD deficiency, which could predispose individuals to other conditions, which may mask G6PD deficiency thereby complicating management.

The G6PD deficiency could be an independent indicator of poor prognosis in some conditions like cancer. According to Wang et al. (2012), G6PD is associated with the progression of gastric cancer. The study identified over-expression of G6PD among the patients presenting with clinical gastric cancer, and these findings correlate significantly with the size of the tumor, survival rate, stage, distant metastasis, lymph node metastasis and the depth of invasion (Wang et al., 2012).

Testing Strategies Could Enhance Safe Management

The study by Domingo et al. (2013) builds on the realization that testing of G6PD deficiency is a vital step toward safe management of the condition. The testing is paramount in lowering the risks to positive patients when deciding appropriate treatment regimes for other diseases associated with G6PD deficiency. The study recommends the need to test G6PD deficiency at the level of the individual to ensure appropriate and safe management. Besides, testing at the population level could give an indication to guide the risk mapping for making policies (Domingo et al., 2013).
The primary pathology in G6PD deficiency is hemolysis, which describes the breakdown of erythrocytes in blood. During the collection of blood specimen for analysis, this hemolysis can take place if a phlebotomist fails to follow appropriate procedures during collection, handling, and storage of sample (Lippi et al., 2011). These pre-analytical problems are of particular concerns to the emergency departments since hemolysed blood may indicate hemolytic anemia even if it is from poor laboratory practices. This issue leads to poor clinical and organization association between the clinicians working in the laboratory and those in the emergency departments (Lippi et al., 2011). Therefore, the development of parameters that identifies suitable specimens such as hemolysis index, differentiation between in vivo and in vitro hemolysis was proposed as the best alternative for this problem. These strategies are appropriate for other clinicians when making diagnosis.

Discussion

Findings show that the prevalence of G6PD deficiency is high in areas with high malaria transmission dynamics. These observations are in tandem with other studies that associated G6PD deficiency with treatment regimes. For instance, previously Luzzatto and Seneca (2013) showed that some pharmacogenetics has clinical implications for patients with G6PD. Examples of these drugs include the Chlorproguanil-dapsone-artesunate treatment and 8-aminoquinolines (Carter et al., 2011). These studies show that these drugs increase the risks of red blood cells hemolysis. However, White et al.’s (2012) findings indicate that the lower dosages of primaquine when administered once could be safe and effective in combination with artemisinin combination treatment in patients with G6PD deficiency. The most important aspect for consideration is the pathophysiological implication of drugs that could deteriorate conditions of patients with G6PD deficiency. Clinicians ought to discriminate medications that worsen the condition of such patients.

Conclusion

The findings show that apart from genetics, pharmacological agents against diseases like malaria act as the primary predisposing factor that could complicate patients’ outcome. Patients suffering from malaria have a high prevalence of G6PD deficiency, and the treatment of such patients may lead to life-threatening episodes for G6PD deficiency patients. Other factors include the fava food, which acts as an inducer for acute severe hemolysis. The main challenges facing the caregivers are proper diagnosis and the selection of appropriate medication for such patients. The information is relevant because it provides existing challenges, which could help the caregivers come up with alternative strategies to improve patient outcome through appropriate identification of the condition and design appropriate drug regimes. These realizations have led to research the lowest dosages of the adverse drugs that could lower adverse outcome and improve patient’s conditions. Although genotyping and phenotyping diagnostic approach could be expensive and may not be readily available for all clinical settings, they provide the standardized approach for selecting appropriate drugs. However, recent developments in the manufacture of kits could improve the caregivers’ effort in the management strategies, though some of the kits reported low sensitivity, they could be improved. Besides, a multi disciplinary approach that take on board specialists from fields like modeling could play a role in identifying parameters of predisposition to guide specific and more targeted research. The testing of G6PD deficiency and appropriate handling of the samples play a significant role in the management by clinicians.

Summary

Recent studies on glucose-6-phosphate dehydrogenase deficiency have majored on the risk factors, testing strategies, and appropriate ways of management. The Glucose-6-phosphate dehydrogenase deficiency is associated with the destruction of erythrocytes rendering them non-functional. Patients present with different symptoms ranging from paleness to jaundice as well as rapid heart rate, shortness of breath and fatigue. The realization that this condition is prevalent in the areas with high malaria transmission and that some anti-malaria drugs complicate the episodes of glucose-6-phosphate dehydrogenase deficiency has informed the evaluation of some drugs and their effects on patients with the condition. This study involved a systematic review of the previous and recent literature on the predisposing factors, testing strategies, and appropriate management approaches that could guide clinicians undertake safe management of the patients. The study involved searching articles from Scopus, PubMed and science direct, which were selected based on search terms and the relevance to the study. The finding shows that pharmacogenetics is the primary predisposing factor and this could guide clinician select appropriate medication that lowers adverse effects on patients. Besides, easy to use testing kits with high sensitivity and specificity could help clinicians manage the condition. The kits that do not require sophisticated instrumental analysis could help clinicians improve the approaches for managing G6PD deficiency and its associated pathophysiology. Some food items could also increase the hemolysis, and clinicians ought to discriminate foodstuffs that predispose patients to hemolytic anemia. These findings are relevant since they guide practitioners on the best strategies for handling patients with the G6PD deficiency for the improved clinical outcome.