A glutamine metabolic switch supports erythropoiesis.

Metabolic requirements vary during development, and our understanding of how metabolic activity influences cell specialization is incomplete. Here, we describe a switch from glutamine catabolism to synthesis required for erythroid cell maturation. Glutamine synthetase (GS), one of the oldest functioning genes in evolution, is activated during erythroid maturation to detoxify ammonium generated from heme biosynthesis, which is up-regulated to support hemoglobin production.

Associated Effect of and Polymorphisms on Iron Overload.

Mutations in the ferroportin (FPN) gene SLC40A1 alter iron recycling and cause disturbances in iron homeostasis. The variants of TMPRSS6 contribute to the development of iron deficiencies. In this study, we determined the role of FPN and TMPRSS6 gene polymorphisms in the modulation of iron homeostasis based on biochemical parameters.

Heme Biosynthetic Gene Expression Analysis With dPCR in Erythropoietic Protoporphyria Patients.

The heme biosynthesis (HB) involves eight subsequent enzymatic steps. Erythropoietic protoporphyria (EPP) is caused by loss-of-function mutations in the ferrochelatase (FECH) gene, which in the last HB step inserts ferrous iron into protoporphyrin IX (PPIX) to form heme. The aim of this work was to for the first time analyze the mRNA expression of all HB genes in peripheral blood samples of patients with EPP having the same genotype FECH c.

Microcytosis in Erythropoietic Protoporphyria.

Partial deficiency of the last enzyme of the heme biosynthetic pathway, namely, ferrochelatase (FECH), is responsible for erythropoietic protoporphyria (EPP) in humans. This disorder is characterized by painful skin photosensitivity, due to excessive protoporphyrin IX (PPIX) production in erythrocytes. Although several papers report the presence of iron deficiency anemia in about 50% of EPP patients, there is still no a conclusive explanation of the why this occurs.

Targeted Next Generation Sequencing and Diagnosis of Congenital Hemolytic Anemias: A Three Years Experience Monocentric Study.

Congenital hemolytic anemias (CHAs) are heterogeneous and rare disorders caused by alterations in structure, membrane transport, metabolism, or red blood cell production. The pathophysiology of these diseases, in particular the rarest, is often poorly understood, and easy-to-apply tools for diagnosis, clinical management, and patient stratification are still lacking. We report the 3-years monocentric experience with a 43 genes targeted Next Generation Sequencing (t-NGS) panel in diagnosis of CHAs; 122 patients from 105 unrelated families were investigated and the results compared with conventional laboratory pathway.

Alternative Pathway Involvement in Protoporphyria Patients Related to Sun Exposure.

The homeostasis of tissues in a chronic disease is an essential function of the alternative pathway (AP) of the complement system (CS). However, if not controlled, it may also be detrimental to healthy cells with a consequent aggravation of symptoms. The protoporphyria (PP) is a rare chronic disease that causes phototoxicity in visible light with local skin pain and general malaise.

Clinical and molecular epidemiology of erythropoietic protoporphyria in Italy.

Background: Erythropoietic protoporphyria (EPP) is a rare inherited disease associated with heme metabolism, characterized by severe life-long photosensitivity and liver involvement.

Objective: To provide epidemiological data of EPP in Italy.

Materials & Methods: Prospective/retrospective data of EPP patients were collected by an Italian network of porphyria specialist centres (Gruppo Italiano Porfiria, GrIP) over a 20-year period (1996-2017).

Targeted resequencing of FECH locus reveals that a novel deep intronic pathogenic variant and eQTLs may cause erythropoietic protoporphyria (EPP) through a methylation-dependent mechanism.

Purpose: Existing data do not explain the reason why some individuals homozygous for the hypomorphic FECH allele develop erythropoietic protoporphyria (EPP) while the majority are completely asymptomatic. This study aims to identify novel possible genetic variants contributing to this variable phenotype.

Methods: High-throughput resequencing of the FECH gene, qualitative analysis of RNA, and quantitative DNA methylation examination were performed on a cohort of 72 subjects.

Common fetal hemoglobin variants in Lebanese patients bearing the codon 29 beta gene mutation associated with different thalassemia phenotypes.

Beta-thalassemia can present with a wide spectrum of phenotypes determined by the coinheritance of α-thalassemia, hereditary persistence of fetal hemoglobin, and polymorphic variants in the BCL11A, HMIP, and HBB clusters. The codon 29 (cd29) mutation in the beta gene has been associated with a broad diversity of thalassemia phenotypes, possibly through genetic modifiers determining the genotype-phenotype relationship. In this study, we evaluated the effect of 10 single nucleotide polymorphisms (SNPs) on β-thalassemia severity in a group of 21 Lebanese patients bearing the cd29 mutation.

Molecular characterization, by digital PCR analysis of four HMBS gene mutations affecting the ubiquitous isoform of Porphobilinogen Deaminase (PBGD) in patients with Acute Intermittent Porphyria (AIP).

Genetic variants in promoters and alternative-splicing lesions require to be experimentally tested in order to validate them as causatives of a disease. The digital PCR (dPCR) approach, which is an alternative to the classical qPCR, is an innovative and a more sensitive method for the detection and quantification of nucleic acids. In the present study, we identified four HMBS gene mutations affecting the ubiquitous isoform of porphobilinogen deaminase (PBGD) and established a dPCR protocol which would be able to detect the different transcripts of this gene.

Digital PCR (dPCR) analysis reveals that the homozygous c.315-48T>C variant in the FECH gene might cause erythropoietic protoporphyria (EPP).

Alterations in the ferrochelatase gene (FECH) are the basis of the phenotypic expressions in erythropoietic protoporphyria. The phenotype is due to the presence of a mutation in the FECH gene associated in trans to the c.315-48 T > C variant in the intron 3.

The assessment of noncoding variant of PPOX gene in variegate porphyria reveals post-transcriptional role of the 5' untranslated exon 1.

The PPOX gene encodes for the protoporphyrinogen oxidase, which is involved in heme production. The partial deficiency of protoporphyrinogen oxidase causes variegate porphyria. The tissue-specific regulation of other heme biosynthetic enzymes is extensively studied, but the information concerning transcriptional and post-transcriptional regulation of PPOX gene expression is scarcely available.

Laboratory diagnosis of thalassemia.

The thalassemias can be defined as α- or β-thalassemias depending on the defective globin chain and on the underlying molecular defects. The recognition of carriers is possible by hematological tests. Both α- and β-thalassemia carriers (heterozygotes) present with microcytic hypochromic parameters with or without mild anemia.

Advances in understanding the pathogenesis of congenital erythropoietic porphyria.

Congenital erythropoietic porphyria (CEP) is a rare genetic disease resulting from the remarkable deficient activity of uroporphyrinogen III synthase, the fourth enzyme of the haem biosynthetic pathway. This enzyme defect results in overproduction of the non-physiological and pathogenic porphyrin isomers, uroporphyrin I and coproporphyrin I. The predominant clinical characteristics of CEP include bullous cutaneous photosensitivity to visible light from early infancy, progressive photomutilation and chronic haemolytic anaemia.

Molecular Basis of β-Thalassemia Intermedia in Erbil Province of Iraqi Kurdistan.

β-Thalassemia intermedia (β-TI) is a clinical term describing a range of clinical phenotypes that are intermediate in severity between the carrier state and β-thalassemia major (β-TM). To characterize the molecular basis of β-TI in Erbil Province, Northern Iraq, 83 unrelated patients were investigated. Detection of β-globin gene mutations was carried out by reverse hybridization assay and direct gene sequencing.

X-chromosomal inactivation directly influences the phenotypic manifestation of X-linked protoporphyria.

X-linked protoporphyria (XLP), a rare erythropoietic porphyria, results from terminal exon gain-of-function mutations in the ALAS2 gene causing increased ALAS2 activity and markedly increased erythrocyte protoporphyrin levels. Patients present with severe cutaneous photosensitivity and may develop liver dysfunction. XLP was originally reported as X-linked dominant with 100% penetrance in males and females.

Congenital erythropoietic porphyria linked to GATA1-R216W mutation: challenges for diagnosis.

Congenital erythropoietic porphyria (CEP) is a rare genetic disease that is characterized by a severe cutaneous photosensitivity causing unrecoverable deformities, chronic hemolytic anemia requiring blood transfusion program, and by fatal systemic complications. A correct and early diagnosis is required to develop a management plan that is appropriate to the patient's needs. Recently only one case of X-linked CEP had been reported, describing the trans-acting GATA1-R216W mutation.

Seven novel genetic mutations within the 5'UTR and the housekeeping promoter of HMBS gene responsible for the non-erythroid form of acute intermittent porphyria.

Acute intermittent porphyria (AIP) is an autosomal dominant disorder caused by molecular abnormalities in the HMBS gene. This gene is transcribed from two promoters to produce ubiquitous and erythroid specific isoforms of porphobilinogen deaminase (PBGD). In the classical form of AIP, both isoforms are deficient, but about 5% of families have the non-erythroid variant in which only the ubiquitous isoform is affected.