First and Second Level Haemoglobinopathies Diagnosis: Best Practices of the Italian Society of Thalassemia and Haemoglobinopathies (SITE)

The purpose of this best practice paper is to review the current recommendations for the identification and prenatal diagnosis of hemoglobinopathies. Methods: The management committee of SITE selected and gathered a multidisciplinary team in order to formulate recommendations based on the available scientific evidence integrated with the opinions of experts, with the purpose of supporting clinicians. Results: We provide recommendations for first level tests (complete blood count, hemoglobin separation and iron balance), second level tests (molecular diagnosis) and prenatal diagnosis. Five Italian experts in hemoglobinopathies were consulted regarding the orientation of prenatal diagnosis, and for each indication, the degree of agreement among the experts has been specified. Conclusions: Best practice recommendations are the final outcome of this translational research and allow transfer to daily clinical practice

A mutation in the TMPRSS6 gene, encoding a transmembrane serine protease that suppresses hepcidin production, in familial iron deficiency anemia refractory to oral iron.

Background Hepcidin plays a key role in body iron metabolism by preventing the release of iron from macrophages and intestinal cells. Defective hepcidin synthesis causes iron loading, while overproduction results in defective reticuloendothelial iron release and iron absorption. Design and Methods We studied a Sardinian family in which microcytic anemia due to defective iron absorption and utilization is inherited as a recessive character. Five members showed iron deficiency anemia that was not responsive to oral iron and only partially responsive to parenteral iron administration. To investigate the involvement of known genes implicated in iron metabolism we carried out linkage analysis with microsatellite markers mapping close to these genes. Afterwards, a genome-wide search was performed. Results No linkage was found between the phenotype of the patients and several known human genes involved in iron metabolism ( DMT1, TF, TFRC, ZIRTL, HAMP, HJV ). Genome-wide scanning by microsatellites and single nucleotide polymorphisms showed a multipoint LOD score of 5.6 on chromosome 22q12.3–13.1, where the matriptase-2 (also known as transmembrane protease, serine 6 or TMPRSS6 ) gene is located. Its murine counterpart ( Tmprss6 ) has recently been found to be an essential component of a pathway that detects iron deficiency and suppresses hepcidin production. Sequencing analysis of TMPRSS6 revealed a homozygous causal mutation, predicting a splicing error and a truncated TMPRSS6 protein in affected members. Homozygous subjects had inappropriately elevated levels of serum and urinary hepcidin. Conclusions The findings of this study suggest that the observed TMPRSS6 mutation leads to overproduction of hepcidin and, in turn, to defective iron absorption and utilization. More generally, they confirm in humans the inhibitory effect of matriptase-2 on hepcidin synthesis already demonstrated in mice

Characterization of Two Cases of Congenital Dyserythropoietic Anemia Type I Shed Light on the Uncharacterized C15orf41 Protein

CDA type I is a rare hereditary anemia, characterized by relative reticulocytopenia, and congenital anomalies. It is caused by biallelic mutations in one of the two genes: (i) CDAN1, encoding Codanin-1, which is implicated in nucleosome assembly and disassembly; (ii) C15orf41, which is predicted to encode a divalent metal ion-dependent restriction endonuclease with a yet unknown function. We described two cases of CDA type I, identifying the novel variant, Y94S, in the DNA binding domain of C15orf41, and the H230P mutation in the nuclease domain of the protein. We first analyzed the gene expression and the localization of C15orf41. We demonstrated that C15orf41 and CDAN1 gene expression is tightly correlated, suggesting a shared mechanism of regulation between the two genes. Moreover, we functionally characterized the two variants, establishing that the H230P leads to reduced gene expression and protein level, while Y94S induces a slight decrease of expression. We demonstrated that C15orf41 endogenous protein exhibits nuclear and cytosolic localization, being mostly in the nucleus. However, no altered nuclear-cytosolic compartmentalization of mutated C15orf41 was observed. Both mutants accounted for impaired erythroid differentiation in K562 cells, and H230P mutant also exhibits an increased S-phase of the cell cycle in these cells. Our functional characterization demonstrated that the two variants have different effects on the stability of the mutated mRNA, but both resulted in impaired erythroid maturation, suggesting the block of cell cycle dynamics as a putative pathogenic mechanism for C15orf41-related CDA I

Simultaneous Automated Determination of Glucose 6-Phosphate Dehydrogenase and 6-Phosphogluconate Dehydrogenase Activities in Whole Blood

Peer Reviewe

Somatic deletion of the normal beta-globin gene leading to thalassaemia intermedia in heterozygous beta-thalassaemic patients

Two β-thalassaemia patients, whose constitutive genotype was β39C/β39C→T, had the clinical phenotype β-thalassaemia intermedia. Analysis of leucocyte DNA showed the presence of the mutated β39C→T-gene exclusively, while the normal β39C-gene was also present in reticulocyte RNA. Deletional analysis of chromosome 11p15.5 on leucocyte DNA showed large deletions including the β-globin gene. Two populations of erythroid progenitors, one heterozygous and the other hemizygous for the β39C→T mutation, were demonstrated in one case. This confirms that, in heterozygous individuals, β-thalassaemia intermedia may be caused by inactivation of the β-locus in trans as a result of chromosome 11p15.5 deletions in a subpopulation of haematopoietic cells

Long-Term Health-Related Quality of Life and Clinical Outcomes in Patients with β-Thalassemia after Splenectomy

Few data are available on the efficacy and safety of splenectomy in patients with transfusion-dependent Beta-Thalassemia Major (β-TM) and on its impact on a patient’s health-related quality of life (HRQoL). We examined the long-term HRQoL of adult patients with β-TM in comparison with those treated with medical therapy by using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). We also evaluated the safety and efficacy of splenectomy. Overall, 114 patients with a median age of 41 years (range 18–62) were enrolled in this cross-sectional study. Twenty-nine patients underwent splenectomy (25.4%) at a median age of 12 years (range 1–32). The median follow-up after splenectomy was 42 years (range 6–55). No statistically significant differences were observed in any of the scales of the SF-36 between splenectomized and not-splenectomized patients. The majority of surgical procedures (96.6%) were approached with open splenectomy. Post-splenectomy complications were reported in eight patients (27.5%): four overwhelming infections, three with pulmonary hypertension, and one with thrombosis. A significantly higher prevalence of cardiovascular comorbidities (58.6 vs. 21.2%, p p = 0.013) was observed in splenectomized patients. These patients, however, required fewer red blood cell units per month, with only 27.6% of them transfusing more than 1 unit per month, compared with 72.9% of the not-splenectomized group. Overall, our data suggest that physicians should carefully consider splenectomy as a possible treatment option in patients with β-TM

Delta-globin gene expression improves sickle cell disease in a humanised mouse model

Sickle cell disease (SCD) is a widespread genetic disease associated with severe disability and multi-organ damage, resulting in a reduced life expectancy. None of the existing clinical treatments provide a solution for all patients. Gene therapy and fetal haemoglobin (HbF) reactivation through genetic approaches have obtained promising, but early, results in patients. Furthermore, the search for active molecules to increase HbF is still ongoing. The delta-globin gene produces the delta-globin of haemoglobin A2 (HbA2). Although expressed at a low level, HbA2 is fully functional and could be a valid anti-sickling agent in SCD. To evaluate the therapeutic potential of a strategy aimed to over-express the delta-globin gene in vivo, we crossed transgenic mice carrying a single copy of the delta-globin gene, genetically modified to be expressed at a higher level (activated), with a humanised mouse model of SCD. The activated delta-globin gene gives rise to a consistent production of HbA2, effectively improving the SCD phenotype. For the first time in vivo, these results demonstrate the therapeutic potential of delta-globin, which could lead to novel approaches to the cure of SCD