Sickle cell anemia, gene targeting

There are currently several methods for analysis of the amplified target DNA. For HIV-1, liquid hybridization with radioactively labeled probes is used (K12). Tests for HLA genes and sickle cell anemia utilize the reverse dot-blot format with a nylon membrane (S3). Each clinical research format has a well-characterized detection method defining the optimum probe concentration, the hybridization times and temperatures, as well as the concentrations of indicator reagents. Table 5 describes the optima and tolerances of a nonradioactive dot-blot assay that uses biotinylated probes and detection by a chemiluminescent substrate and a strepta-vidin-HRP conjugate. 

Laboratory findings include low hemoglobin (Hgb) level and increased reticulocyte, platelet, and white blood cell (WBC) counts. The peripheral blood smear demonstrates sickle forms (see Fig. 101-5). Presentation of patients with HbSC disease is less severe than that of SCA, and is characterized primarily by mild anemia (Hgb levels above 9 g/dL), infrequent episodes of pain, persistence of splenomegaly into adult life, and excessive target cells in the peripheral blood smear. In patients with heterozygous HbS and /3-thalassemia gene, severity of disease depends on the thalassemia gene involved. ... 

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