 Alpha thylacemia is a genetic disorder characterized by anemia and a clinical phenotype that varies from asymptomatic to lethal. It is caused by deletion of one or two copies of the alpha genes on chromosome 16, resulting in a decrease in the number of functional alpha-globin genes. The disease can be classified according to its genotype-phenotype correlation, with four possible levels of severity, mild, moderate, severe, and lethal. Molecular analysis is usually required to confirm the diagnosis. HBH disease is characterized by anemia with variable amounts of HBH 0.8 to 40 percent, while hemoglobin BART's hydrox fetalis syndrome is a lethal form in which no alpha-globin is synthesized. Genetic counseling is offered to couples at risk for these conditions, and carriers of alpha-plus or alpha-zero thylacemia alleles generally do not need treatment. HBH patients may require intermittent transfusion therapy during illness, while most pregnancies in which the fetus has hemoglobin BART's hydrox fetalis syndrome are terminated due to increased risks of maternal and fetal morbidity. This article was authored by Higgs-Douglass R. and Hartevel Connelly-Sell. We are article.tv, links in the description below.