Haplotype mapping of a major quantitative-trait locus for fetal hemoglobin production, on chromosome 6q23

Fetal hemoglobin (Hb F) and fetal cell (FC) levels in adults show considerable variation and are influenced by several genetic variants; the major determinants appear to be unlinked to the beta-globin gene cluster. Recently, a trans-acting locus controlling Hb F and FC production has been mapped to chromosome 6q23 in an Asian Indian kindred that includes individuals with heterocellular hereditary persistence of Hb F (HPFH) associated with beta thalassemia. We have extended the kindred by 57 members, bringing the total studied to 210, and have saturated the region with 26 additional markers. Linkage analysis showed tight linkage of the quantitative-trait locus (QTL) to the anonymous markers D6S976 (LOD score 11.3; recombination fraction .00) and D6S270 (LOD score 7.4; recombination fraction .00). Key recombination events now place this QTL within a 1-2-cM interval spanning approximately 1.5 Mb between D6S270 and D6S1626. Furthermore, haplotype analysis has led to a reevaluation of the genealogy and to the identification of additional relationships in the kindred.

Alpha interferon in the treatment of chronic hepatitis C infection in thalassaemia major

Hepatitis C virus (HCV) is responsible for the majority of cases of post transfusion non-A non-B (NANB) hepatitis in thalassaemia major (TM). Twelve multi-transfused TM patients with serological, biochemical, histological and molecular biological evidence of HCV infection have been treated for 6 months with recombinant alpha-interferon (IFN). Ten (83%) responded as assessed by a fall of at least 50% of pre-treatment serum transaminase levels. Histological improvement was observed in 6/7 responders tested. Natural killer (NK) cell activity 24 h after the first dose of IFN was significantly increased in responders as compared to non-responders (P < 0.05). HCV RNA disappeared from serum in 5/12 and from liver tissue in 2/5 of the responders. The degree of induction of peripheral blood mononuclear cell 2'5' oligoadenylate synthetase messenger RNA (2-5 OAS mRNA), an enzyme induced by IFN, after the first dose of IFN did not correlate with response. IFN was generally well tolerated. We conclude that the response rate in multi-transfused TM patients infected with HCV and treated with IFN is similar to that in non-multi-transfused patients.