Sickle Cell Disease

Test

• Isoelectric focusing, HPLC, SSCP analysis

Genetics

• Autosomal recessive
• 1:375 to 1:1667 African-Americans
• 1:58,000 in whites in US

Pathology

• Three overlapping groups
• Structural variants:  HbS and HbC, caused by single amino acid substitutions
• Thalassemias, which all have a reduced rate of synthesis of one or more of the globin chains of hemoglobin
• hereditary persistence of fetal hemoglobin (HbF continues to be made after infancy)

Diagnosis

• Clinical diagnosis rarely made before one year of age
• Dactylitis (hand-foot syndrome) is an early manifestation.  Overwhelming sepsis may occur before other symptoms.  10% mortality due to sepsis or splenic sequestration.
• Aseptic necrosis of bones, leg ulcers, neoproliferative retinopathy, serious infections (particularly with encapsulated organisms due to functional asplenism), renal concentrating defects, and delayed growth and sexual maturation.

Treatment

• Penicillin prophylaxis
• Immunization against pneumococcal, H. flu and meningococcal infection.
• Treatment of crises

Acknowledgment

Also see other Inborn Errors of Metabolism.
 

Genetics

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