Sickle cell disease
From IDWiki
Background
- Genetic mutation of the hemoglobin beta chain, most commonly an E6V substitution, causing the formation of hemoglobin S
- Most common in people with African ancestry, though also occurs in Hispanic, southern European, Middle Eastern, and Indian people
- Life expectancy is 20-30 years shorter
Clinical Manifestations
- Chronic anemia
Crises
- Four major sickle crises:
- Vasoocclusive pain crisis
- Hemolytic crisis
- Aplastic crisis (often associated with parvovirus)
- Splenic sequestration crisis
Diagnosis
- Hemoglobin quantification can help to identify the type of sickle cell disease
- HbS is sickle hemoglobin
- HbA is normal adult hemoglobin and HbA2 is the minor variant of adult hemoglobin
- HbF is fetal hemoglobin
- HbC is a hemoglobin variant that causes sickle cell disease when paired with HbS
| Genotype | Hb (g/L) | HbS (%) | HbA (%) | HbA2 (%) | HbF (%) | HbC (%) |
|---|---|---|---|---|---|---|
| AS (trait) | normal | ≤40 | >60 | <3.5 | ≤1 | |
| SS | 60-90 | >90 | <3.5 | <10 | ||
| Sβ0-thalassemia | 70-90 | >80 | >3.5 | <20 | ||
| Sβ+-thalassemia | 90-120 | >60 | 10-30 | >3.5 | <20 | |
| SC | 90-140 | 50 | <3.5 | ≤1 | 45 |
