Acquired Glucose-6-Phosphate Dehydrogenase Deficiency

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a hereditary condition caused by mutations on chromosome X and is transmitted by a sex-linked inheritance. However, impairment of G6PD activity may result from biochemical mechanisms that are able to inhibit the enzyme in specific clinical conditions in the absence of a structural gene-level defect. In this narrative review, a number of clinical settings associated with an "acquired" G6PD deficiency, phenotypically undistinguishable from the primary deficiency, as well as the mechanisms involved, were examined. Hyperaldosteronism and diabetes are the most common culprits of acquired G6PD deficiency. Additional endocrine and metabolic conditions may cause G6PD deficiency in both hospitalized and outpatients. Contrary to the inherited defect, acquired G6PD deficiency is a condition that is potentially curable by removing the factor responsible for enzyme inhibition. Awareness regarding acquired G6PD deficiency by physicians might result in improved recognition and treatment.

Keywords: G6PD deficiency; acquired disease; endocrinopathies; oxidative stress.

Figure 1

Regulation of G6PD activity and potential inhibitory mechanisms. Aldosterone downregulates the expression of G6PD mRNA through the stimulation of the synthesis of cyclic adenosine monophosphate (cAMP), that binds the tetrameric form of Protein Kinase A (PKA). PKA phosphorylates the transcription factor cAMP response element-binding protein (CREB), thereby eventually blocking the transcription of the G6PD gene. Thyroid hormones bind to the thyroid receptor (TR), forming a heterodimer with the retinoid receptor (RXR) and activating G6PD mRNA transcription.

Figure 2

Flowchart of the diagnostic process in case of suspected acquired G6PD deficiency.