Molecular Characterization of Glucose-6-phosphate Dehydrogenase Deficiency in Oman

Objectives

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most encountered abnormality of red blood cell metabolism worldwide and has a high prevalence in Oman. The objective of the study was to characterize the mutation variants of G6PD deficiency in a cohort of the Omani population with partial and complete enzyme deficiency.

Methods

This prospective study included newborns and children less than one year of age with partial or complete G6PD enzyme deficiency identified on routine screening using a fluorescent spot test from 31 January 2017 to 12 September 2017 in Sultan Qaboos University Hospital. The identified samples were analyzed for the presence of C563T, G1003A, and other mutations using direct DNA sequencing of the polymerase chain reaction.

Results

Out of 3679 newborn samples screened, 21.0% were found to have complete or partial G6PD enzyme deficiency. A total of 145 participants were included in the genetic analysis, of which 133 (91.7%) were completely deficient in G6PD enzyme activity and 12 (8.3%) had partial deficiency. The Mediterranean variant (C563T) was identified in 129 (89.0%). Other variants were found as follows: eight (5.5%) had variant A-, three (2.1%) had the Chatham variant (G1003A), one (0.7%) had the Cosenza variant, and one (0.7%) had exon 11 variant. No mutation was found in two subjects.

Conclusions

The most common mutation in the Omani population is the Mediterranean mutation (C563T) followed by the variant A- mutation. However, not all participants were found to have a mutation.

Etiology and Outcomes of Thrombotic Microangiopathies

BACKGROUND AND OBJECTIVES

Thrombotic microangiopathies constitute a diagnostic and therapeutic challenge. Secondary thrombotic microangiopathies are less characterized than primary thrombotic microangiopathies (thrombotic thrombocytopenic purpura and atypical hemolytic and uremic syndrome). The relative frequencies and outcomes of secondary and primary thrombotic microangiopathies are unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective study in a four-hospital institution in 564 consecutive patients with adjudicated thrombotic microangiopathies during the 2009-2016 period. We estimated the incidence of primary and secondary thrombotic microangiopathies, thrombotic microangiopathy causes, and major outcomes during hospitalization (death, dialysis, major cardiovascular events [acute coronary syndrome and/or acute heart failure], and neurologic complications [stroke, cognitive impairment, or epilepsy]).

RESULTS

We identified primary thrombotic microangiopathies in 33 of 564 patients (6%; thrombotic thrombocytopenic purpura: 18 of 564 [3%]; atypical hemolytic and uremic syndrome: 18 of 564 [3%]). Secondary thrombotic microangiopathies were found in 531 of 564 patients (94%). A cause was identified in 500 of 564 (94%): pregnancy (35%; 11 of 1000 pregnancies), malignancies (19%), infections (33%), drugs (26%), transplantations (17%), autoimmune diseases (9%), shiga toxin due to Escherichia coli (6%), and malignant hypertension (4%). In the 31 of 531 patients (6%) with other secondary thrombotic microangiopathies, 23% of patients had sickle cell disease, 10% had glucose-6-phosphate dehydrogenase deficiency, and 44% had folate deficiency. Multiple causes of thrombotic microangiopathies were more frequent in secondary than primary thrombotic microangiopathies (57% versus 19%; P<0.001), and they were mostly infections, drugs, transplantation, and malignancies. Significant differences in clinical and biologic differences were observed among thrombotic microangiopathy causes. During the hospitalization, 84 of 564 patients (15%) were treated with dialysis, 64 of 564 patients (11%) experienced major cardiovascular events, and 25 of 564 patients (4%) had neurologic complications; 58 of 564 patients (10%) died, but the rates of complications and death varied widely by the cause of thrombotic microangiopathies.

CONCLUSIONS

Secondary thrombotic microangiopathies represent the majority of thrombotic microangiopathies. Multiple thrombotic microangiopathies causes are present in one half of secondary thrombotic microangiopathies. The risks of dialysis, neurologic and cardiac complications, and death vary by the cause of thrombotic microangiopathies.