Novel mutations in the ferritin-L iron-responsive element that only mildly impair IRP binding cause hereditary hyperferritinaemia cataract syndrome.

BACKGROUND: Hereditary Hyperferritinaemia Cataract Syndrome (HHCS) is a rare autosomal dominant disease characterized by increased serum ferritin levels and early onset of bilateral cataract. The disease is caused by mutations in the Iron-Responsive Element (IRE) located in the 5' untranslated region of L-Ferritin (FTL) mRNA, which post-transcriptionally regulates ferritin expression. METHODS: We describe two families presenting high serum ferritin levels and juvenile cataract with novel mutations in the L-ferritin IRE. The mutations were further characterized by in vitro functional studies. RESULTS: We have identified two novel mutations in the IRE of L-Ferritin causing HHCS: the Badalona +36C > U and the Heidelberg +52 G > C mutation. Both mutations conferred reduced binding affinity on recombinant Iron Regulatory Proteins (IPRs) in EMSA experiments. Interestingly, the Badalona +36C > U mutation was found not only in heterozygosity, as expected for an autosomal dominant disease, but also in the homozygous state in some affected subjects. Additionally we report an update of all mutations identified so far to cause HHCS. CONCLUSIONS: The Badalona +36C > U and Heidelberg +52 G > C mutations within the L-ferritin IRE only mildly alter the binding capacity of the Iron Regulatory Proteins but are still causative for the disease.

Screening for the beta-thalassaemia trait: hazards among populations of West African Ancestry.

The aim of this study was to examine the accuracy and characteristics of detecting the beta-thalassaemia trait in populations of West African ancestry. School children, aged 16-19 years, in Manchester Parish, Jamaica were screened to detect the genes which could give rise to offspring with sickle cell disease. Haematological indices and HbA(2) levels in subjects with an MCH ≤ 26 pg and an RDW < 18.0 with DNA analysis in those with indices consistent with the beta thalassaemia trait were measured. The performance of published discriminant indices in distinguishing iron deficiency and beta-thalassaemia trait in this population was assessed. Of 10,148 subjects, 1,739 (17.1%) had an AA haemoglobin phenotype and red cell indices consistent with beta-thalassaemia (MCH values ≤ 26 pg, RDW < 18.0) requiring estimations of HbA(2) levels. HbA(2) levels were ≥3.5% in 112 and beta-thalassaemia mutations were identified in 77 of these including the -88 C>T mutation in 35 (45%), -29 A>G in 19 (25%), -90 C>T in 7 (9%), the IVS II-849 A>G in 5 (6%) with smaller contributions from five other mutations. Discriminant indices performed poorly in the differentiation of iron deficiency and the beta-thalassaemia trait. Detection of the beta-thalassaemia trait is relatively insensitive in populations of West African ancestry partly because of the mild defects characterising beta-thalassaemia in this population and also the high prevalence of deletional alpha thalassaemia. More sensitive indicators are required for beta-thalassaemia detection to inform such populations at risk of offspring with sickle cell disease.

Activating NOTCH1 mutations predict favorable early treatment response and long-term outcome in childhood precursor T-cell lymphoblastic leukemia.

Activating mutations of the transmembrane receptor NOTCH1 are common in precursor T-cell lymphoblastic leukemia (T-ALL). We systematically analyzed the impact of activating NOTCH1 mutations on early treatment response and long-term outcome in 157 patients with T-ALL of the pediatric ALL-Berlin-Frankfurt-Munster (BFM) 2000 study. We confirm previous results that NOTCH1 mutations occur in more than 50% of T-ALL in children. In 82 patients (82/157; 52.2%), activating NOTCH1 mutations were identified either in the heterodimerization (55/82; 67.1%), in the PEST (13/82; 15.9%), or in both domains (14/82; 17.0%). The presence of NOTCH1 mutations was significantly correlated with a good prednisone response and favorable minimal residual disease (MRD) kinetics, which was independent from sex, age, white blood cell count, and T-cell immunophenotype at the time of diagnosis. Furthermore, activating NOTCH1 mutations specified a large subgroup of patients with an excellent prognosis. These findings indicate that in the context of the ALL-BFM 2000 treatment strategy, NOTCH1 mutations predict a more rapid early treatment response and a favorable long-term outcome in children with T-ALL.

The cytokine macrophage migration inhibitory factor reduces pro-oxidative stress-induced apoptosis.

The cytokine macrophage migration inhibitory factor (MIF) exhibits pro- and anti-inflammatory activities and regulates cell proliferation and survival. We investigated the effects of MIF on apoptosis. As MIF exhibits oxidoreductase activity and participates in regulating oxidative cell stress, we studied whether MIF could affect oxidative stress-induced apoptosis. We demonstrated that MIF exhibits antiapoptotic activity in various settings. MIF suppressed camptothecin-induced apoptosis in HeLa and Kym cells and HL-60 promyeloblasts. Both exogenous MIF and endogenous MIF, induced following overexpression through tetracycline (tet) gene induction, led to significant suppression of apoptosis. Apoptosis reduction by MIF was also observed in T cells. A role for MIF in redox stress-induced apoptosis was addressed by comparing the effects of rMIF with those of the oxidoreductase mutant C60SMIF. Endogenous overexpression of C60SMIF was similar to that of MIF, but C60SMIF did not suppress apoptosis. Exogenous rC60SMIF inhibited apoptosis. A role for MIF in oxidative stress-induced apoptosis was directly studied in HL-60 leukocytes and tet-regulated HeLa cells following thiol starvation or diamide treatment. MIF protected these cells from redox stress-induced apoptosis and enhanced cellular glutathione levels. As overexpressed C60SMIF did not protect tet-regulated HeLa cells from thiol starvation-induced apoptosis, it seems that the redox motif of MIF is important for this function. Finally, overexpression of MIF inhibited phosphorylation of endogenous c-Jun induced by thiol starvation, indicating that MIF-based suppression of apoptosis is mediated through modulation of c-Jun N-terminal kinase activity. Our findings show that MIF has potent antiapoptotic activities and suggest that MIF is a modulator of pro-oxidative stress-induced apoptosis.