Review: the sickle hemoglobinopathies--genetic analyses of common phenocopies and new molecular approaches to treatment.

Within the very large group of sickle cell hemoglobinopathies several phenocopy clusters exist. These can be conveniently classified as: 1) conditions in which HbA and S are present, 2) disorders where HbS is the predominant hemoglobin, and 3) the HbSF phenotype. This review will focus on distinguishing the genotype of these common phenocopies as well as new potential approaches to therapy.