Abstract Topic: 26. Sickle cell disease
Background: Hemoglobin SOman is a sickle hemoglobinopathy that results from two mutations in Beta globin chain, at position 6 and 121; (B6 Glu>>>Val) and (B121 Glu>>>Lys). At cellular level, Hb SOman has a super-sickling tendency more than the classic Hb S, due to the additional mutation (B121 Glu>>>Lys). Previously, it has been reported in only 5 carriers that the disease has variable clinical features based on the presence of alpha thalassemia trait and the expression of Hb SOman level.
Aims: Our aim is to study the disease clinical and hematological characteristics, focusing on phenotype/genotype correlation and association with alpha thalassemia.
Methods: This is a cross-sectional descriptive study of 69 patients confirmed to have Hb SOman trait. 60 patients were tested for alpha thalassemia and their clinical and hematological profile were analyzed.
Results: A total number of Hb SOman trait patients was 69. The mean age was 27.5 years; males and females were affected equally (Table 1). Alpha thalassemia trait (_α/_α) was co-inherited in 73% of Hb SOman patients, 20% were carriers (_α/ αα) and 7% were normal genotype (αα/ αα). There was no significant clinical course and hematological characteristics differences between patients of HbSOman with alpha thalassemia trait or without alpha thalassemia. However, HbSOman level was found to be the most specific factor associated with increased clinical severity (P<≤ 0.001).
Summary/Conclusion: Hb SOman trait phenotype can present with severe manifestation similar to SCD and co-inheritance of alpha thalassemia trait does not affect its severity. Hb SOman level correlates well with disease severity.
Table I: Demographic, clinical and laboratory data of all patients n=69
| Clinical profile | Mean | SEM | |
|---|---|---|---|
| Gender (n) | 34 Male; 35 Female | ||
| Age (years) | 27.5 | 3.05 | |
| Wilayat | Nakhal n (%) | 35(50.7%) | |
| Bahla n (%) | 24(34.7%) | ||
| Sumail n (%) | 4(5.7%) | ||
| Alaamerat n (%) | 6(8.6%) | ||
| Severity (%) | 52 Mild; 48 severe | ||
| HbS-Oman (%) | 16.69 | 0.54 | |
| HbF (%) | 4.16 | 0.30 | |
| HbA2 (%) | 3.99 | 0.08 | |
| Hb (g/l) | 11.64 | 0.26 | |
| Platelets (x 103/uL) | 275 | 12.92 | |
| ANC (x 103/uL) | 3.08 | 0.70 | |
| Vaso-occlusive crisis(VOC) n (%) | 37(53%) | ||
| Simple Blood transfusion n (%) | 13(19.9%) | ||
| Exchange transfusion n (%) | 7(10.8%) | ||
| ACS n (%) | 11(17.2%) | ||
| Stroke n (%) | 3(4.7%) | ||
| Splenic sequestration n (%) | 4(6.2%) | ||
| Gallstones n (%) | 1(1.5%) | ||
| Avascular necrosis n (%) | 5(7.7%) | ||
| Osteomyelitis n (%) | 1(1.5%) | ||
| Iron overload/chelation therapy n (%) | 1(1.5%) | ||
| Hydroxyurea n (%) | 11(17.2%) | ||
| Surgeries (splenectomy/cholecystectomy/joint replacement) n (%) | 2(3%) | ||
| Bone Marrow Transplantation(BMT) | 0(0%) | ||
| Death | 0(0%) | ||
Keywords: Sickle cell