title: Concordant fetal hemoglobin response to hydroxyurea in siblings with sickle cell disease.
abstract: Fetal hemoglobin (HbF) level and the HbF responses to hydroxyurea (HU) vary among patients with sickle cell disease and are, at least in part, genetically regulated. We hypothesized that siblings with sickle cell disease are likely to share the same parental beta-like globin gene clusters with their cis-acting regulatory sequences and therefore, if regulation of this response is linked to the beta-globin gene cluster, might have concordant HbF responses to HU. Accordingly, we studied 26 families (30 sib pairings), 20 with sickle cell anemia (three families had three siblings) and 6 families with HbS-beta-thalassemia (one family had three siblings, and one family consisted of monozygotic twins), to see if siblings with sickle cell disease had discordant or concordant changes in HbF during HU treatment. Intraclass correlation coefficients (r) showed a high, positive correlation between sibs for HbF levels before and during HU treatment and a concordant change in HbF response from baseline to treatment-associated levels. Changes in mean corpuscular volume (MCV) paralleled HbF levels, while the expected correlations between treatment-associated fall in leukocyte count and increase in MCV were also present. Our results provide additional evidence that some elements that regulate HbF expression are linked to the beta-globin gene cluster.
authors.affiliation: Boston University School of Medicine, Room 211, 88 E. Newton Street, Boston, MA 02118, USA. msteinberg@medicine.bu.edu
authors.forename: Martin H
authors.initials: MH
authors.lastname: Steinberg
authors.forename: Ersi
authors.initials: E
authors.lastname: Voskaridou
authors.forename: Abdullah
authors.initials: A
authors.lastname: Kutlar
authors.forename: Dimitris
authors.initials: D
authors.lastname: Loukopoulos
authors.forename: Mabel
authors.initials: M
authors.lastname: Koshy
authors.forename: Samir K
authors.initials: SK
authors.lastname: Ballas
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Castro
authors.forename: Franca
authors.initials: F
authors.lastname: Barton
mesh_terms: D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000097:blood / Q000188:drug therapy* / Q000235:genetics; D004909:Erythrocyte Indices; D005192:Family Health; D005260:Female; D005319:Fetal Hemoglobin / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D005914:Globins / Q000235:genetics; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology* / Q000627:therapeutic use; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D005810:Multigene Family / Q000235:genetics; D009154:Mutation; D012189:Retrospective Studies; D035781:Siblings
chemical_list: D005914:Globins; D005319:Fetal Hemoglobin; D006918:Hydroxyurea