A novel G6PD gene variant in a Chinese girl with favism.

BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. The human G6PD gene is highly polymorphic, and over 200 mutations have been identified, many of which are associated with hemolytic anemia. Here, we analyzed the clinical genetics data of a Chinese girl with favism who developed acute hemolytic anemia after fava bean ingestion. METHODS: The clinical genetics data of the proband who developed acute hemolytic anemia were collected and analyzed, and G6PD gene exons were sequenced in the proband and her family. RESULTS: We reported for the first time a novel G6PD gene variant in a Chinese girl, which we named "G6PD Wuhan." This variant is localized exon 3 of the G6PD gene at genomic position 141G > C, that is a change from p.Lys47 to Asn. The bioinformatics analysis and protein modeling study indicated this variant may have negative effects on the enzyme activity of G6PD. CONCLUSIONS: Our results indicated that favism in the proband was caused by this novel heterozygous variant (c.141G > C) in G6PD. The variant in G6PD has implications for genetic counseling and could provide insights into the functional roles of G6PD mutations.

Hepatic transcriptional profiling response to fava bean-induced oxidative stress in glucose-6-phosphate dehydrogenase-deficient mice.

Favism is an acute hemolytic syndrome caused by the ingestion of fava bean (FB) in glucose 6-phosphate dehydrogenase (G6PD) deficient individuals. However, little is known about the global transcripts alteration in liver tissue after FB ingestion in G6PD-normal and -deficient states. In this study, deep sequencing was used to analyze liver genes expression alterations underlying the effects of FB in C3H (Wild Type, WT) and G6PD-deficient (G6PDx) mice and to evaluate and visualize the collective annotation of a list of genes to Gene Ontology (GO) terms associated with favism. Our results showed that FB resulted in a decrease of glutathione (GSH)-to-oxidized glutathione (GSSG) ratio and an increase of malondialdehyde (MDA) both in the G6PDx and WT-control check (CK) mice plasma. Significantly, liver transcript differences were observed between the control and FB-treated groups of both WT and G6PDx mice. A total of 320 differentially expressed transcripts were identified by comparison of G6PDx-CK with WT-CK and were associated with immune response and oxidation-reduction function. A total of 149 differentially expressed genes were identified by comparison of WT-FB with WT-CK. These genes were associated with immune response, steroid metabolic process, creatine kinase activity, and fatty acid metabolic process. A total of 438 differential genes were identified by comparing G6PDx-FB with G6PD-CK, associated with the negative regulation of fatty acid metabolic process, endoplasmic reticulum, iron binding, and glutathione transferase activity. These findings indicate that G6PD mutations may affect the functional categories such as immune response and oxidation-reduction.

An unusual syncope cause in the ED: favism.

Favism is an acute hemolytic syndrome occurring in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals after the consumption of fava beans. The highest incidence is in boys aged 2-6 years. We report a 56-year-old man presented to the emergency department (ED) with recurrent syncope attacks due to favism. In our knowledge, this is the first report of favism-caused syncope in an adult patient without a G6PD deficiency diagnosis in the past and diagnosed in ED.

Mechanical hemolysis of cross-bonded red cells in the microcirculation.

In favic crises the effective surface area of red cells is reduced by a mechanism called membrane cross bonding (Fischer et al., Brit. J. Haematol. 59, 159, 1985). In these crises massive intravascular hemolysis is observed the cause of which is unknown. One possibility is mechanical hemolysis of cross-bonded red cells that cannot negotiate the microcirculation due to their decreased effective surface area. To investigate this possibility critical phenomena of red cell behavior in the microcirculation were studied using Laplace's law. In model calculations an idealized vessel geometry was used: a funnel in which the angle of the conical part and the radius of the cylindrical part were varied. A map of these two parameters was established showing where red cells either enter the funnel or get stuck and where they would hemolyse under a pressure difference of 3 mm Hg. Adopting a teleological point of view it was assumed that red cell and vessel geometry are mutually adapted. Based on this assumption those combinations of the two parameters cone angle and radius were found that allow the passage of the complete population of normal red cells without hemolysis. Assuming a reduction in red cell surface area similar to that observed in favic crises it was found that only a small portion of the population would hemolyse. Therefore, mechanical hemolysis may not suffice to explain the observed intravascular hemolysis.