Beta-thalassemia intermedia due to compound heterozygosity for two beta-globin gene promoter mutations, including a novel TATA box deletion.

ABSTRACT

An 8-year-old African-American boy had a clinical history consistent with mild beta-thalassemia intermedia with moderate anemia, microcytosis, reticulocytosis, and splenomegaly. He was asymptomatic and did not require transfusion. At age 4 years, hemoglobin (Hb) electrophoresis showed Hb A = 37.8%, Hb A(2) = 5.0%, and Hb F = 56.1%. At age 8 years, he was diagnosed to be a compound heterozygote for two beta-globin gene promoter mutations, the relatively common nucleotide (nt) -88 C --> T mutation from the cap site, and a novel two-nucleotide (AA) deletion between nt -29 and -26 within the TATA box of the beta-globin gene. His mother and 14-year-old brother were simple heterozygotes for this novel (AA) deletion. Both heterozygotes had normal Hb level, borderline microcytosis, and elevated Hb A(2).