Publications (76) View all
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Article: Congenital dyserythropoietic anemia type II: molecular analysis and expression of the SEC23B gene.
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ABSTRACT: Congenital dyserythropoietic anemia type II (CDAII), the most common form of CDA, is an autosomal recessive condition. CDAII diagnosis is based on invasive, expensive, and time consuming tests that are available only in specialized laboratories. The recent identification of SEC23B mutations as the cause of CDAII opens new possibilities for the molecular diagnosis of the disease. The aim of this study was to characterize molecular genomic SEC23B defects in 16 unrelated patients affected by CDAII and correlate the identified genetic alterations with SEC23B transcript and protein levels in erythroid precursors. SEC23B was sequenced in 16 patients, their relatives and 100 control participants. SEC23B transcript level were studied by quantitative PCR (qPCR) in peripheral erythroid precursors and lymphocytes from the patients and healthy control participants. Sec23B protein content was analyzed by immunoblotting in samples of erythroblast cells from CDAII patients and healthy controls. All of the investigated cases carried SEC23B mutations on both alleles, with the exception of two patients in which a single heterozygous mutation was found. We identified 15 different SEC23B mutations, of which four represent novel mutations: p.Gln214Stop, p.Thr485Ala, p.Val637Gly, and p.Ser727Phe. The CDAII patients exhibited a 40-60% decrease of SEC23B mRNA levels in erythroid precursors when compared with the corresponding cell type from healthy participants. The largest decrease was observed in compound heterozygote patients with missense/nonsense mutations. In three patients, Sec23B protein levels were evaluated in erythroid precursors and found to be strictly correlated with the reduction observed at the transcript level. We also demonstrate that Sec23B mRNA expression levels in lymphocytes and erythroblasts are similar. In this study, we identified four novel SEC23B mutations associated with CDAII disease. We also demonstrate that the genetic alteration results in a significant decrease of SEC23B transcript in erythroid precursors. Similar down-regulation was observed in peripheral lymphocytes, suggesting that the use of these cells might be sufficient in the identification of Sec23B gene alterations. Finally, we demonstrate that decreased Sec23B protein levels in erythroid precursors correlate with down-regulation of the SEC23B mRNA transcript.Orphanet Journal of Rare Diseases 12/2011; 6:89. · 5.83 Impact Factor -
Article: Changing patterns of splenectomy in transfusion-dependent thalassemia patients.
American Journal of Hematology 09/2011; 86(9):808-10. · 4.67 Impact Factor -
Article: On T2* magnetic resonance and cardiac iron.
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ABSTRACT: Measurement of myocardial iron is key to the clinical management of patients at risk of siderotic cardiomyopathy. The cardiovascular magnetic resonance relaxation parameter R2* (assessed clinically via its reciprocal, T2*) measured in the ventricular septum is used to assess cardiac iron, but iron calibration and distribution data in humans are limited. Twelve human hearts were studied from transfusion-dependent patients after either death (heart failure, n=7; stroke, n=1) or transplantation for end-stage heart failure (n=4). After cardiovascular magnetic resonance R2* measurement, tissue iron concentration was measured in multiple samples of each heart with inductively coupled plasma atomic emission spectroscopy. Iron distribution throughout the heart showed no systematic variation between segments, but epicardial iron concentration was higher than in the endocardium. The mean ± SD global myocardial iron causing severe heart failure in 10 patients was 5.98 ± 2.42 mg/g dry weight (range, 3.19 to 9.50 mg/g), but in 1 outlier case of heart failure was 25.9 mg/g dry weight. Myocardial ln[R2*] was strongly linearly correlated with ln[Fe] (R²=0.910, P<0.001), leading to [Fe]=45.0×(T2*)⁻¹·²² for the clinical calibration equation with [Fe] in milligrams per gram dry weight and T2* in milliseconds. Midventricular septal iron concentration and R2* were both highly representative of mean global myocardial iron. These data detail the iron distribution throughout the heart in iron overload and provide calibration in humans for cardiovascular magnetic resonance R2* against myocardial iron concentration. The iron values are of considerable interest in terms of the level of cardiac iron associated with iron-related death and indicate that the heart is more sensitive to iron loading than the liver. The results also validate the current clinical practice of monitoring cardiac iron in vivo by cardiovascular magnetic resonance of the midseptum.Circulation 03/2011; 123(14):1519-28. · 14.74 Impact Factor -
Article: Worldwide survey of T2* cardiovascular magnetic resonance in Thalassaemia
Journal of Cardiovascular Magnetic Resonance. 01/2011; -
Article: A pilot trial of deferiprone for neurodegeneration with brain iron accumulation.
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ABSTRACT: Deferiprone was shown to reverse iron deposition in Friedreich's ataxia. This multi-center, unblinded, single-arm pilot study evaluated safety and efficacy of deferiprone for reducing cerebral iron accumulation in neurodegeneration with brain iron accumulation. Four patients with genetically-confirmed pantothenate kinase-associated neurodegeneration, and 2 with parkinsonism and focal dystonia, but inconclusive genetic tests, received 15 mg/kg deferiprone bid. Magnetic resonance imaging and neurological examinations were conducted at baseline, six and 12 months. Chelation treatment caused no apparent hematologic or neurological side effects. Magnetic resonance imaging revealed decreased iron accumulation in the globus pallidus of 2 patients (one with pantothenate kinase-associated neurodegeneration). Clinical rating scales and blinded video rating evaluations documented mild-to-moderate motor improvement in 3 patients (2 with pantothenate kinase-associated neurodegeneration). These results underline the safety and tolerability of deferiprone, and suggest that chelating treatment might be effective in improving neurological manifestations associated with iron accumulation. (Clinicaltrials.gov Identifier: NTC00907283).Haematologica 07/2011; 96(11):1708-11. · 6.42 Impact Factor
