Coinheritance of PIEZO1 variants and multi-locus red blood cell defects account for the symptomatic phenotype in beta-thalassemia carriers.

Workflow of the study with some examples of the achieved results.

Clinical exome-based panel testing for medically actionable secondary findings in a cohort of 383 Italian participants.

Background: Next-generation sequencing-based genetic testing represents a great opportunity to identify hereditary predispositions to specific pathological conditions and to promptly implement health surveillance or therapeutic protocols in case of disease. The term secondary finding refers to the active search for causative variants in genes associated with medically actionable conditions. Methods: We evaluated 59 medically actionable ACMG genes using a targeted in silico analysis of clinical exome sequencing performed in 383 consecutive individuals referred to our Medical Genetics Unit. A three-tier classification system of SFs for assessing their clinical impact and supporting a decision-making process for reporting was established. Results: We identified SFs with high/moderate evidence of pathogenicity in 7.0% (27/383) of analyzed subjects. Among these, 12/27 (44.4%) were carriers of a high-risk recessive disease allele. The most represented disease domains were cancer predisposition (33.3%), cardiac disorders (16.7%), and familial hypercholesterolemia (12.5%). Conclusion: Although still debated, ensuring during NGS-based genetic testing an opportunistic screening might be valuable for personal and familial early management and surveillance of medically actionable disorders, the individual's reproductive choices, and the prevalence assessment of underestimated hereditary genetic diseases.

SEC23B Loss-of-Function Suppresses Hepcidin Expression by Impairing Glycosylation Pathway in Human Hepatic Cells.

Biallelic pathogenic variants in the SEC23B gene cause congenital dyserythropoietic anemia type II (CDA II), a rare hereditary disorder hallmarked by ineffective erythropoiesis, hemolysis, erythroblast morphological abnormalities, and hypo-glycosylation of some red blood cell membrane proteins. Abnormalities in SEC23B, which encodes the homonymous cytoplasmic COPII (coat protein complex II) component, disturb the endoplasmic reticulum to Golgi trafficking and affect different glycosylation pathways. The most harmful complication of CDA II is the severe iron overload. Within our case series (28 CDA II patients), approximately 36% of them exhibit severe iron overload despite mild degree of anemia and slightly increased levels of ERFE (the only erythroid regulator of hepcidin suppression). Thus, we hypothesized a direct role of SEC23B loss-of-function in the pathomechanism of hepatic iron overload. We established a hepatic cell line, HuH7, stably silenced for SEC23B. In silenced cells, we observed significant alterations of the iron status, due to both the alteration in BMP/SMADs pathway effectors and a reduced capability to sense BMP6 stimulus. We demonstrated that the loss-of-function of SEC23B is responsible of the impairment in glycosylation of the membrane proteins involved in the activation of the BMP/SMADs pathway with subsequent hepcidin suppression. Most of these data were confirmed in another hepatic cell line, HepG2, stably silenced for SEC23B. Our findings suggested that the pathogenic mechanism of iron overload in CDA II is associated to both ineffective erythropoiesis and to a specific involvement of SEC23B pathogenic variants at hepatic level. Finally, we demonstrated the ability of SEC23B paralog, i.e., SEC23A, to rescue the hepcidin suppression, highlighting the functional overlap between the two SEC23 paralogs in human hepatic cells.

Rapid and portable, lab-on-chip, point-of-care genotyping for evaluating clopidogrel metabolism.

BACKGROUND: Dual antiplatelet therapy with aspirin and a platelet P2Y12 receptor inhibitors (clopidogrel, prasugrel, ticagrelor) is a cornerstone of antithrombotic treatment in patients with acute coronary syndromes (ACS). Clopidogrel has been the standard of care for nearly a decade; however, its clinical efficacy is influenced by a considerable inter-patient variability in response, clearly associated to cytochrome P (CYP) enzyme genetic variations. We used a novel point-of-care lab-on-chip instrument to genotype ACS patients in order to identify carriers of the ATB-binding cassette ABCB1 3435, CYP2C19*2 and CYPC2C19*17 alleles and adjust the pharmacological approach accordingly. METHODS AND RESULTS: Between October 2012 and January 2013, 160 ACS patients were enrolled at the Cardiology Unit of the Ospedale Niguarda Cà Granda and genotyped at the patients' point-of-care using the newly developed Q3 portable real-time PCR instrument, which remarkably scored the CYP2C19*2, CYP2C19*17, and ABCB1 3435 alleles in a time of 70 min from DNA extraction to final genotype calls; concordance with the other gold-standard genotyping techniques was 100%. CONCLUSIONS: The Q3 instrument proved to be as reliable as the current conventional techniques. As genotyping in the ACS setting cannot be delegated to centralised clinical laboratories for reasons of time, genotyping at the patients' bedside provides an opportunity to conduct large-scale randomised trials in order to assess whether adding genotype data to clinical variables improves clinical outcomes.