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Severe chronic rhinosinusitis in children should alert clinicians and extensive CFTR genotyping should be performed. We propose that thorough clinical and functional assessment in severe chronic rhinosinusitis is valuable to discover rare mutations which could be treated by CFTR correctors to postpone pulmonary infection.

International audience; No abstract available

International audience; TIn families without a Cystic Fibrosis (CF) history, fetal ultrasound bowel abnormalities can unexpectedly reveal the disease. Isolated or in association, the signs can be fetal bowel hyperechogenicity, intestinal loop dilatation and non-visualization of fetal gallbladder. In these cases, search for CF transmembrane conductance regulator (CFTR) gene mutations is part of the recommended diagnostic practices, with a search for frequent mutations according to ethnicity, and, in case of the triad of signs, with an exhaustive study of the gene. However, the molecular diagnosis remains a challenge in populations without well-known frequent pathogenic variants. We present a multiethnic cohort of 108 pregnancies with fetal bowel abnormalities in which the parents benefited from an exhaustive study of the CFTR gene. We describe the new homozygous p.Cys1410* mutation in a fetus of African origin. We did not observe the most frequent p.Phe508del mutation in our cohort but evidenced variants undetected by our frequent mutations kit. Thanks to the progress of sequencing techniques and despite the difficulties of interpretation occasionally encountered, we discuss the need to carry out a comprehensive CFTR study in all patients in case of fetal bowel abnormalities.

In families without a Cystic Fibrosis (CF) history, fetal ultrasound bowel abnormalities can unexpectedly reveal the disease. Isolated or in association, the signs can be fetal bowel hyperechogenicity, intestinal loop dilatation and non-visualization of fetal gallbladder. In these cases, search for CF transmembrane conductance regulator (CFTR) gene mutations is part of the recommended diagnostic practices, with a search for frequent mutations according to ethnicity, and, in case of the triad of signs, with an exhaustive study of the gene. However, the molecular diagnosis remains a challenge in populations without well-known frequent pathogenic variants. We present a multiethnic cohort of 108 pregnancies with fetal bowel abnormalities in which the parents benefited from an exhaustive study of the CFTR gene. We describe the new homozygous p.Cys1410* mutation in a fetus of African origin. We did not observe the most frequent p.Phe508del mutation in our cohort but evidenced variants undetected by our frequent mutations kit. Thanks to the progress of sequencing techniques and despite the difficulties of interpretation occasionally encountered, we discuss the need to carry out a comprehensive CFTR study in all patients in case of fetal bowel abnormalities.

Whether multiple single nucleotide polymorphisms (SNPs) of BCL11A and HBS1L-MYB genes affect hemoglobin (Hb)F production and hematological parameter variation in β-thalassemia/HbE and homozygous HbE in Thai subjects with low and high HbF levels are still unclear. Three SNPs of BCL11A gene (rs1427407, rs10189857 and rs11886868) and 3 SNPs of HBS1L-MYB gene (rs4895441, rs9399137 and rs28384513) were analyzed in 45 β-thalassemia/HbE patients who had HbF levels lower and higher than 15 %, and in 50 homozygous HbE who had HbF levels lower and higher than 5 %. Their hematological parameters were measured using automated blood counter. The HbF level was analyzed using high performance liquid chromatography (HPLC). There were no statistical significant differences of allele and genotype frequencies of 3 SNPs in the BCL11A gene between the groups of β-thalassemia/HbE patients and homozygous HbE subjects with low and high HbF levels. Significant differences in the allele frequencies in HBS1L-MYB SNP rs4895441 (p = 0.041) and rs9399137 (p = 0.048) were observed in homozygous HbE subjects with HbF £ 5 % and > 5 %. Moreover, significant differences in MCV (p = 0.005) and trends towards significant differences in MCH (p = 0.057) and HbF levels (p = 0.051) were found in HBS1L-MYB SNP rs9399137 of homozygous HbE subjects. Therefore, the HBS11L-MYB SNPs especially rs9399137 had an effect on HbF production and the variation of hematological parameters in homozygous HbE subjects, but not in β-thalassemia/HbE patients.

Molecules correcting the trafficking (correctors) and gating defects (potentiators) of the cystic fibrosis causing mutation c.1521_1523delCTT (p.Phe508del) begin to be a useful treatment for CF patients bearing p.Phe508del. This mutation has been identified in different genetic contexts, alone or in combination with variants in cis. Until now, 21 exonic variants in cis of p.Phe508del have been identified, albeit at a low frequency. The aim of this study was to evaluate their impact on the efficacy of CFTR-directed corrector/potentiator therapy (Orkambi). The analysis by minigene showed that two out of 15 cis variants tested increased exon skipping (c.609C > T and c.2770G > A). Four cis variants were studied functionally in the absence of p.Phe508del, one of which was found to be deleterious for protein maturation c.1399C > T (p.Leu467Phe). In the presence of p.Phe508del, this variant was the only to prevent the response to Orkambi treatment. This study showed that some patients carrying p.Phe508del complex alleles are predicted to poorly respond to corrector/potentiator treatments. Our results underline the importance to validate treatment efficacy in the context of complex alleles.

International audience; Most of the 2,000 variants identified in the CFTR (cystic fibrosis transmembrane regulator) gene are rare or private. Their interpretation is hampered by the lack of available data and resources, making patient care and genetic counseling challenging. We developed a patient-based database dedicated to the annotations of rare CFTR variants in the context of their cis- and trans-allelic combinations. Based on almost 30 years of experience of CFTR testing, CFTR-France (https://cftr.iurc.montp.inserm.fr/cftr) currently compiles 16,819 variant records from 4,615 individuals with cystic fibrosis (CF) or CFTR-RD (related disorders), fetuses with ultrasound bowel anomalies, newborns awaiting clinical diagnosis, and asymptomatic compound heterozygotes. For each of the 736 different variants reported in the database, patient characteristics and genetic information (other variations in cis or in trans) have been thoroughly checked by a dedicated curator. Combining updated clinical, epidemiological, in silico, or in vitro functional data helps to the interpretation of unclassified and the reassessment of misclassified variants. This comprehensive CFTR database is now an invaluable tool for diagnostic laboratories gathering information on rare variants, especially in the context of genetic counseling, prenatal and preimplantation genetic diagnosis. CFTR-France is thus highly complementary to the international database CFTR2 focused so far on the most common CF-causing alleles.

International audience

We present a rapid strategy based on Restriction Fragment Length Polymorphism (RFLP) analysis to characterize the more frequent glucose 6-phosphate dehydrogenase (G6PD) variants observed in a population with high gene flow. During a study involving more than 600 patients, we observed mainly G6PD A(-) (c.202G>A, c.376A>G; p.Val68Met, p.Asn126Asp), G6PD Mediterranean (Med) (c.563C>T, p.Ser188Phe), and G6PD Betica (c.376A>G, 542A>T; p.126Asn>Asp, 181Asp>Val) with addition of a few rare ones. A number of 10 abnormalities amounted to 92% of all the molecular defects. In addition, seven new mutations were found: three presented with acute hemolytic anemia following oxidative stress [G6PD Nice (c.1380G>C, p.Glu460Asp), G6PD Roubaix (c.811G>C, p.Val271Leu), and G6PD Toledo (c.496C>T, p.Arg166Cys)], three with different degrees of chronic hemolytic anemia [G6PD Lille (c.821A>T, p.Glu274Val), G6PD Villeurbanne (c.1000_1002delACC, p.Thr334del), and G6PD Amiens (c.1367A>T, p.Asp456Val)] and one found fortuitously G6PD Montpellier (c.1132G>A, p.Gly378Ser).

Intro: Dyserythropoiesis is a growing class of inherited diseases of various severities in which genes encoding for proteins involved in cellular trafficking, chromatin dynamic or transacting factors restricted to red cells maturation, are mutated. Belonging to this later groups, several mutation in GATA 1, an X linked transacting factor, were associated with dyserytropoietic anemia frequently associated with a thrombopenia. Case report: Our case is the second living child of a mother from Greek origin and a father from French origin. This couple had a first girl without any evidenced abnormality. During the second pregnancy, the male fetus had a severe anemia (Hb: 3.8 g/dL), regenerative (erythroblasts: 176 G/L). He received intrauterine transfusions but the worsening of anemia led to interrupt the pregnancy at 33 weeks. A third pregnancy was terminated because of a Down’s syndrome. A fourth pregnancy revealed the recurrence of a severe anemia at 27 weeks in a male fetus (Hb: 3.2 g/dl). Two intrauterine transfusions allowed the birth at 33 weeks of an anemic boy (at birth Hb 10.6 g/dL, reticulocytes: 261 G/L; erythroblasts: 647G/L). A myelogram was made when he was 3 months old, and showed a severe dyserythropoiesis, with a hypoplastic red cells lineage and a blockade on late erythroblasts. The megakaryocyte lineage appeared to be normal. He received Packed RBC up to 3 month, then Hb level stabilized spontaneously, with at the latest control, when he was aged 7 months, an Hb level at 10.9g/dl, MCV: 88 fL; reticulocytes: 152 G/L; circulating erythroblasts: 7%. Platelets count is 152 G/L. Leucocytes: 13.5 G/L, with PNN: 3.0 G/L, lymphocytes: 7.3 G/L, eosinophils: 1.4 G/L. Genetic analysis in the family and cultivated cells: The available members of the family were extensively studied including globins locus (mutation and deletion), KLF 1, GATA 1, Bcl11a, CDN 1, sec 23B and MPL gene. The exome analysis of the living boy revealed no other genetic defect. In order to get evidence on the pathogenic consequence of the GATA-1 mutation, mRNA were extracted from BFUE obtained from the mother and were searched for the mutation (PCR digestion using Ade I/Dra III and Sanger sequencing) seeking for a "non random" X inactivation Results: Two locus were found to carry a mutation: GATA-1, p.Arg202Thr, NM_00249.3 (GATA-1):c.605G>C) and MPL: p.Trp474Arg, NM_005373.2(MPL_v001):c.1420T>C). The terminated fetus (male) and the living boy were found to be heterozygous for the MPL mutant and hemizygous for the GATA-1 mutant both mutations are inherited from the mother. and the sister is only heterozygous for the MPL mutant (fig 1). The father carries no mutation. The mRNA analysis of independent BFUE clones showed the presence of the wild type GATA-1 messenger into 26 from 28 colonies analysed ( 30 clones, 2 PCR fail). Discussion and conclusion: GATA -1 is a zinc finger transacting factor know to be necessary for the late erythroblasts maturation through the binding onto specific DNA targets with the Cter ZF (aa 258 to 293) and the interaction with FOG with Nter ZF (aa 202 to 248). Mutations affecting the Cter zinc finger would prevent the DNA binding and thus should result in a lethal phenotype as it was described in GATA-1 KO mice model. Several GATA-1 mutations involving the Nter ZF are described (M205V, G208R, G208S, D218G) and are involved in dyserythropoiesis usually with mild anemia. Here we describe a new mutation affecting a highly conserved aa belonging to the Nter ZF. In hemizygous patients, it produces a phenotype very close to that of cases previously described, but more restricted to the erythroid lineage as the only consequence on the thrombopoiesis is, up to now, only a small decrease in platelets count. This case may indicate that the functions of GATA-1 / FOG may differ between fetal and adult erythropoiesis as anemia seems to be worse in the fetal period. However, we evidenced a strong skewed X-chromosome inactivation toward wild type allele in the mother's erythroblasts which is a strong argument for a marked impairment of the interaction and/or the function of the GATA-1Arg202Thr /FOG complex. Figure 1: family pedigree and GATA-1 / MPL genotype Figure 1:. family pedigree and GATA-1 / MPL genotype Disclosures No relevant conflicts of interest to declare.