The Val16Ala polymorphism in the superoxide dismutases 2 (SOD2) protein is associated with low serum levels of the protein and may predict the severity of sickle cell disease (SCD), according to a new study published in the Mediterranean Journal of Hematology and Infectious Diseases.

Oxidative stress plays a crucial role in SCD pathophysiology and superoxide dismutases protect cells from oxidative stress. In the case of SOD2 deficiency, oxidized red cell proteins accumulate, the rate of hemoglobin oxidation increases, and the deformability and survival of red cell membranes decrease.

In the present study, a team of researchers led by Ilham Youssry, MD, from the Department of Pediatrics, Faculty of Medicine at Cairo University in Egypt assessed the effect of the Val16Ala polymorphism in SOD2 on the levels of the protein and its potential impact on the severity of SCD.

Read more about the pathophysiology of SCD

The team genotyped the SOD2 Val16Ala polymorphism in 100 patients with SCD and 100 age-matched healthy controls. The genotypic and allelic frequencies of the Val16Ala polymorphism were similar in patients with SCD and healthy controls.

The results showed that serum levels of SOD2 were significantly lower in people with the Val16Ala polymorphism. Moreover, the levels of serum SOD2 inversely correlated with the annual rate of hospitalization, which could be considered a predictor of disease complications. In other words, the lower the levels of serum SOD2 the higher the rate of hospitalization, and the higher the levels of SOD2, the lower the rates of hospitalization.

The researchers concluded that serum levels of SOD2 could help predict disease severity in SCD. They said that larger studies are necessary to evaluate whether genetic variations in the SOD2 gene contribute to the disease-associated complications and to better understand the pathogenesis of SCD.


Khorshied MM, Shaheen IA, Selim YMM, Elshahawy AO, Youssry I. Impact of superoxide dismutase genetic polymorphism (SOD2 Val16Ala) and superoxide dismutase level on disease severity in a cohort of Egyptian sickle cell disease patients. Mediterr J Hematol Infect Dis. 2022;14(1):e2022037. doi:10.4084/MJHID.2022.037