Different hematologic phenotypes are associated with the leftward (-alpha 4.2) and rightward (-alpha 3.7) alpha+-thalassemia deletions.

Journal article

We have compared the phenotypes of the two common deletion forms of alpha+-thalassemia by analysis of umbilical cord blood samples from Melanesia. Homozygotes for the leftward, 4.2-kilobase, deletion (-alpha 4.2) had significantly higher levels of Hb Bart's at birth than homozygotes for the rightward, 3.7-kilobase, deletion (-alpha 3.7). Compound heterozygotes for each deletion had intermediate values. Although deletion forms of alpha 0 thalassemia were not found in this survey, nondeletion alpha-thalassemia was present at low frequency. Since the predominant rightward deletion in this population, -alpha 3.7III, entirely removes the alpha 1-gene and the 4.2-kilobase deletion deletes the alpha 2-gene, these data indicate that the alpha 2-globin gene has a higher output than the alpha 1-gene, on single alpha-gene chromosomes.

Authors: Bowden, D; Hill, A; Higgs, D; Oppenheimer, S; Weatherall, D

• Publication status: Published
• Journal: Journal of clinical investigation
• Volume: 79
• Issue: 1
• Pages: 39-43
• Publication date: 1987-01-01
• DOI: 10.1172/jci112804
• EISSN: 1558-8238
• ISSN: 0021-9738
• Language: English
• Keywords: Chromosome Deletion; Gene Expression Regulation; Globins; Melanesia; Heterozygote; Hemoglobins, Abnormal; Humans; Phenotype; Thalassemia; Homozygote