Diet Challenge in G6PD Deficient Egyptian Children: A One- Year Prospective Single Center Study with Genotype - Phenotype Correlation

Background: Glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent and add a burden on families in Egypt and Middle East due to lifelong diet restriction. Non-fava beans diet is the main food for most families in the region and parents and doctors consider it as a prohibited food whatever the genetic or clinical phenotype of G6PD. The effective management is avoiding a spectrum of food and drugs causing oxidative stress. No data is available about the hazards of consumption of non-fava beans diet.

Aim: To investigate the effect of challenge of non-fava beans diet on occurrence of hemolysis in both common and rare mutations causing G6PD deficiency in Egyptian children as well as making a genotype-phenotype correlation.

Patients and Methods: An interventional study registered in the Clinical Trials Government (NCT02498340) and included all G6PD deficient children who were regularly followed up in Pediatric Hematology Center, Ain Shams University over last decade from 2004-2014 who stopped eating non fava-bean diet since their diagnosis as G6PD deficient and willing to participate in the diet challenge. They were enrolled in a one year prospective study involved quantitative analyses for enzymatic activity, and molecular typing of G6PD enzyme using a polymerase chain reaction-amplification refractory mutation system (PCR-ARMS) technique. Patient's medical records were reviewed as history of blood transfusion and G6PD level at diagnosis. Initial phase was dietetic challenge with ingestion of non-fava beans taken in small amount (10-20 gm/day for 3 successive days) for children with haemoglobin level ≥ 11 gm/dl with daily clinical and laboratory monitoring by complete blood count, and markers of hemolysis as well as measurement of MDA level both basal and at study end. A drop of Hb of 1.0 gm/dl and / or appearance of hemoglobinuria is considered a significant hemolysis. Patients who did not met the definition of significant hemolysis were prospectively followed up for one year with follow up during their chronic exposure by CBC and hemolysis markers/ 3 months.

Results: 108 G6PD deficient patients were enrolled; their ages ranged between 1-12 year, (mean of 3.1±1.2) with a male to female ratio of 8:1. Genotypes were; Mediterranean variant in 53%, Cairo in 13% and African mutations in 16%. Rare mutations as Chatham in 4%, Santmaria in 1% and Asahi in 1%; were described in Egypt for the first time. As regard the initial clinical presentation, 17 (15.7%), were asymptomatic; (6 had Mediterranean variant (2 silent polymorphism), 2 the Cairo variant, one the Chatham variant, one in the Asahi variant and in seven patients the molecular variant was not identified. History of blood transfusion was reported in79% in Mediterranean variant, 61.5% in Cairo variant , 56% in African variant, 50% in Chatham variant, and in none of the santmaria and Asahi variants. However no significant relation was detected between mutations and classes of G6PD deficiency(severity) and also with blood transfusion requirement among studied cases. Neonatal jaundice was observed in 56.4% of studied patients with the highest percentage in Mediterranean variant. Clinical diversity showed 83% symptomatic; 64% received blood transfusion, history of ingestion of fava beans was reported in 70% while 61 % had history of neonatal jaundice. The G6PD enzyme level was significantly lowered in Mediterranean and African mutation compared to other mutations (P< 0.01) but it was not correlated with disease clinical severity. No hemolysis was reported after dietetic challenge in all different genotypes (no hemoglobinuria and absence of markers of hemolysis). No drop of Hb over a one year period of chronic consumption of non-fava beans diet. Moreover no significant difference was found between baseline hemoglobin and MDA and their levels at the study end (p>0.05).

Conclusion: Chronic ingestion of small amount of non-fava beans once weekly for one year was not associated with haemolysis or increase in oxidative stress in this cohort of G6PD deficient children in all variants. Improved family satisfaction with 92% of patients accepted to continue food challenge with a great satisfaction. Mediterranean mutation was the most common variant. Three rare non-Middle-East mutations were reported for first time; namely Santamaria, chatham and Asahi.