Hemoglobin shows a decrease in Hb A 2 . Caused by decreased synthesis of beta chains. Symptoms of anemia, splenomegaly, icterus. Cells are microcytic. Examination of peripheral smear shows target cells, cigar-shaped cells, and basophilic stippling.
Genetic counseling is necessary.
Both genes for beta-chain synthesis defective or missing. Manifestations begin at approximately 4 to 6 months of life. There is pronounced wasting, jaundice, slow growth and development, and delayed onset of secondary sex features. The patient will have skeletal abnormalities secondary to bone marrow expansion. Hb electrophoresis shows large amounts of Hb F, variable amounts of Hb A, and increased Hb A 2 .