title: HbA2 levels in normal adults are influenced by two distinct genetic mechanisms.
abstract: Using a genome-wide association study, we found that common inter-individual differences in haemoglobin A(2)  (HbA(2) , α(2) δ(2) ) levels are largely governed by genetic factors (42% of variability). The influence of age (1%) and sex (4%) was small. HbA(2)  levels were influenced by two loci: the HBS1L-MYB locus on chromosome 6q, which has been shown to have pleiotropic effects on other haematological traits; and a second locus surrounding HBB, the gene encoding β-globin. Our results suggest that HbA(2)  levels in adults are influenced by two different biological processes: one via kinetics of erythropoiesis, and the other, via competition between HBB and HBD activity.
authors.affiliation: Molecular Haematology, James Black Centre, King's College London, 125 Coldharbour Lane, London, UK.
authors.forename: Stephan
authors.initials: S
authors.lastname: Menzel
authors.forename: Chad
authors.initials: C
authors.lastname: Garner
authors.forename: Helen
authors.initials: H
authors.lastname: Rooks
authors.forename: Tim D
authors.initials: TD
authors.lastname: Spector
authors.forename: Swee Lay
authors.initials: SL
authors.lastname: Thein
mesh_terms: D000328:Adult; D055106:Genome-Wide Association Study / Q000379:methods; D006443:Hemoglobin A2 / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D012016:Reference Values
chemical_list: D006443:Hemoglobin A2