A. Characteristics

1. Hemoglobin composed of one HbS and one HbC chain
   1. Hemoglobin (Hb) S has a mutation in the ß chain leading to position 6 Glu to Val
   2. HbC has ß chain position 6 Glu to Lys
2. HbC is more permissive for sickling than HbA (adult normal form of Hb)
3. Moderate to moderately severe anemia
4. Usually the disease is less malignant than HbSS

B. Symptoms and Signs

1. Splenomegaly / Splenic Sequestration
2. Aseptic necrosis of the femoral head
3. Retinal Disease
   1. Retinal vessel proliferation
   2. Annual ophthalmological surveillance
   3. Laser therapy for new vessels
4. Renal Disease may occur
   1. Papillary necrosis is most common
   2. Intermittent hematuria occurs
5. Infrequent vaso-occlusive episodes
   1. Pulmonary disease
   2. Particularly during and after pregnancy
   3. Treated with exchange transfusions

C. Blood Smear

1. Target cells in large numbers
2. Moderate numbers of helmet cells

D. Mortality [2]

1. Median age at death: 60 years for men, 68 years for women
2. Compare with mean age for Sickle Cell Disease with 42 years for men, 48 years for women

References

1. Weatherall DJ and Provan AB. 2000. Lancet. 355(9120):1169
2. Platt OS, Brambilla DJ, Rosse WF, et al. 1994. NEJM. 330(23):1639