@article {10745, title = {Loss-of-function mutations in cause a new form of inherited thrombocytopenia.}, journal = {Blood}, volume = {133}, year = {2019}, month = {2019 Mar 21}, pages = {1346-1357}, abstract = {

Inherited thrombocytopenias (ITs) are a heterogeneous group of disorders characterized by low platelet count that may result in bleeding tendency. Despite progress being made in defining the genetic causes of ITs, nearly 50\% of patients with familial thrombocytopenia are affected with forms of unknown origin. Here, through exome sequencing of 2 siblings with autosomal-recessive thrombocytopenia, we identified biallelic loss-of-function variants in This gene encodes for a receptor-like PTP, PTPRJ (or CD148), which is expressed abundantly in platelets and megakaryocytes. Consistent with the predicted effects of the variants, both probands have an almost complete loss of PTPRJ at the messenger RNA and protein levels. To investigate the pathogenic role of PTPRJ deficiency in hematopoiesis in vivo, we carried out CRISPR/Cas9-mediated ablation of (the ortholog of human ) in zebrafish, which induced a significantly decreased number of CD41 thrombocytes in vivo. Moreover, megakaryocytes of our patients showed impaired maturation and profound defects in SDF1-driven migration and formation of proplatelets in vitro. Silencing of in a human megakaryocytic cell line reproduced the functional defects observed in patients{\textquoteright} megakaryocytes. The disorder caused by mutations presented as a nonsyndromic thrombocytopenia characterized by spontaneous bleeding, small-sized platelets, and impaired platelet responses to the GPVI agonists collagen and convulxin. These platelet functional defects could be attributed to reduced activation of Src family kinases. Taken together, our data identify a new form of IT and highlight a hitherto unknown fundamental role for PTPRJ in platelet biogenesis.

}, issn = {1528-0020}, doi = {10.1182/blood-2018-07-859496}, author = {Marconi, Caterina and Di Buduo, Christian A and LeVine, Kellie and Barozzi, Serena and Faleschini, Michela and Bozzi, Valeria and Palombo, Flavia and McKinstry, Spencer and Lassandro, Giuseppe and Giordano, Paola and Noris, Patrizia and Balduini, Carlo L and Savoia, Anna and Balduini, Alessandra and Pippucci, Tommaso and Seri, Marco and Katsanis, Nicholas and Pecci, Alessandro} } @article {10748, title = {ACTN1 mutations lead to a benign form of platelet macrocytosis not always associated with thrombocytopenia.}, journal = {Br J Haematol}, volume = {183}, year = {2018}, month = {2018 Oct}, pages = {276-288}, abstract = {

The inherited thrombocytopenias (IT) are a heterogeneous group of diseases resulting from mutations in more than 30 different genes. Among them, ACTN1-related thrombocytopenia (ACTN1-RT; Online Mendelian Inheritance in Man: 615193) is one of the most recently identified forms. It has been described as a mild autosomal dominant macrothrombocytopenia caused by mutations in ACTN1, a gene encoding for one of the two non-muscle isoforms of α-actinin. We recently identified seven new unrelated families with ACTN1-RT caused by different mutations. Two of them are novel missense variants (p.Trp128Cys and p.Pro233Leu), whose pathogenic role has been confirmed by in~vitro studies. Together with the 10 families we have previously described, our cohort of ACTN1-RT now consists of 49 individuals carrying ACTN1 mutations. This is the largest case series ever collected and enabled a critical evaluation of the clinical aspects of the disease. We concluded that ACTN1-RT is the fourth most frequent form of IT worldwide and it is characterized by platelet macrocytosis in all affected subjects and mild thrombocytopenia in less than 80\% of cases. The risk of bleeding, either spontaneous or upon haemostatic challenge, is negligible and there are no other associated defects, either congenital or acquired. Therefore, ACTN1-RT is a benign form of IT, whose diagnosis provides affected individuals and their families with a good prognosis.

}, issn = {1365-2141}, doi = {10.1111/bjh.15531}, author = {Faleschini, Michela and Melazzini, Federica and Marconi, Caterina and Giangregorio, Tania and Pippucci, Tommaso and Cigalini, Elena and Pecci, Alessandro and Bottega, Roberta and Ramenghi, Ugo and Siitonen, Timo and Seri, Marco and Pastore, Annalisa and Savoia, Anna and Noris, Patrizia} } @article {10421, title = {Hypomorphic FANCA mutations correlate with mild mitochondrial and clinical phenotype in Fanconi anemia.}, journal = {Haematologica}, volume = {103}, year = {2018}, month = {2018 Mar}, pages = {417-426}, abstract = {

Fanconi anemia is a rare disease characterized by congenital malformations, aplastic anemia, and predisposition to cancer. Despite the consolidated role of the Fanconi anemia proteins in DNA repair, their involvement in mitochondrial function is emerging. The purpose of this work was to assess whether the mitochondrial phenotype, independent of genomic integrity, could correlate with patient phenotype. We evaluated mitochondrial and clinical features of 11 affected individuals homozygous or compound heterozygous for p.His913Pro and p.Arg951Gln/Trp, the two residues of FANCA that are more frequently affected in our cohort of patients. Although p.His913Pro and p.Arg951Gln proteins are stably expressed in cytoplasm, they are unable to migrate in the nucleus, preventing cells from repairing DNA. In these cells, the electron transfer between respiring complex I-III is reduced and the ATP/AMP ratio is impaired with defective ATP production and AMP accumulation. These activities are intermediate between those observed in wild-type and FANCA-/- cells, suggesting that the variants at residues His913 and Arg951 are hypomorphic mutations. Consistent with these findings, the clinical phenotype of most of the patients carrying these mutations is mild. These data further support the recent finding that the Fanconi anemia proteins play a role in mitochondria, and open up possibilities for genotype/phenotype studies based on novel mitochondrial criteria.

}, issn = {1592-8721}, doi = {10.3324/haematol.2017.176131}, author = {Bottega, Roberta and Nicchia, Elena and Cappelli, Enrico and Ravera, Silvia and De Rocco, Daniela and Faleschini, Michela and Corsolini, Fabio and Pierri, Filomena and Calvillo, Michaela and Russo, Giovanna and Casazza, Gabriella and Ramenghi, Ugo and Farruggia, Piero and Dufour, Carlo and Savoia, Anna} } @article {8503, title = {Clinical and pathogenetic features of ETV6 related thrombocytopenia with predisposition to acute lymphoblastic leukemia.}, journal = {Haematologica}, year = {2016}, month = {2016 Jun 30}, abstract = {

ETV6-related thrombocytopenia (ETV6-RT) is an autosomal dominant thrombocytopenia that has been recently identified in a few families and has been suspected to predispose to hematological malignancies. To gain further information on this disorder, we searched for ETV6 mutations in the 130 families with inherited thrombocytopenia of unknown origin from our cohort of 274 consecutive pedigrees with familial thrombocytopenia. We identified 20 ETV6-RT patients from 7 pedigrees. They have 5 different ETV6 variants, including three novel mutations affecting the highly conserved E26 transformation-specific domain. The relative frequency of ETV6-RT resulted 2.6\% in the whole case series and 4.6\% among the families with known forms of inherited thrombocytopenia. The degree of thrombocytopenia and bleeding tendency of ETV6-RT patients were mild, but 4 subjects developed B-cell acute lymphoblastic leukemia during childhood, resulting in a significantly increased incidence compared to the general population. Clinical and laboratory findings did not identify any peculiar defects that can be used to suspect this disorder by routine diagnostic workup. However, at variance with most inherited thrombocytopenias, platelet size was not enlarged. In vitro studies revealed that patients megakaryocytes have defective maturation and impaired proplatelet formation. Moreover, ETV6-RT platelets have reduced ability to spread on fibrinogen. Since also the dominant thrombocytopenias due to mutations in RUNX1 and ANKRD26 are characterized by normal platelet size and predispose to hematological malignancies, we suggest that mutation screening of ETV6, RUNX1 and ANKRD26 should be performed in all the subjects with autosomal dominant thrombocytopenia and normal platelet size.

}, issn = {1592-8721}, doi = {10.3324/haematol.2016.147496}, author = {Melazzini, Federica and Palombo, Flavia and Balduini, Alessandra and De Rocco, Daniela and Marconi, Caterina and Noris, Patrizia and Gnan, Chiara and Pippucci, Tommaso and Bozzi, Valeria and Faleschini, Michela and Barozzi, Serena and Doubek, Michael and Di Buduo, Christian A and Stano Kozubik, Katerina and Radova, Lenka and Loffredo, Giuseppe and Pospisilova, Sarka and Alfano, Caterina and Seri, Marco and Balduini, Carlo L and Pecci, Alessandro and Savoia, Anna} } @article {8350, title = {Evaluation of energy metabolism and calcium homeostasis in cells affected by Shwachman-Diamond syndrome.}, journal = {Sci Rep}, volume = {6}, year = {2016}, month = {2016}, pages = {25441}, abstract = {

Isomorphic mutation of the SBDS gene causes Shwachman-Diamond syndrome (SDS). SDS is a rare genetic bone marrow failure and cancer predisposition syndrome. SDS cells have ribosome biogenesis and their protein synthesis altered, which are two high-energy consuming cellular processes. The reported changes in reactive oxygen species production, endoplasmic reticulum stress response and reduced mitochondrial functionality suggest an energy production defect in SDS cells. In our work, we have demonstrated that SDS cells display a Complex IV activity impairment, which causes an oxidative phosphorylation metabolism defect, with a consequent decrease in ATP production. These data were confirmed by an increased glycolytic rate, which compensated for the energetic stress. Moreover, the signalling pathways involved in glycolysis activation also appeared more activated; i.e. we reported AMP-activated protein kinase hyper-phosphorylation. Notably, we also observed an increase in a mammalian target of rapamycin phosphorylation and high intracellular calcium concentration levels ([Ca(2+)]i), which probably represent new biochemical equilibrium modulation in SDS cells. Finally, the SDS cell response to leucine (Leu) was investigated, suggesting its possible use as a therapeutic adjuvant to be tested in clinical trials.

}, issn = {2045-2322}, doi = {10.1038/srep25441}, author = {Ravera, Silvia and Dufour, Carlo and Cesaro, Simone and Bottega, Roberta and Faleschini, Michela and Cuccarolo, Paola and Corsolini, Fabio and Usai, Cesare and Columbaro, Marta and Cipolli, Marco and Savoia, Anna and Degan, Paolo and Cappelli, Enrico} } @article {3633, title = {ACTN1-related thrombocytopenia: identification of novel families for phenotypic characterization.}, journal = {Blood}, volume = {125}, year = {2015}, month = {2015 Jan 29}, pages = {869-72}, abstract = {

Inherited thrombocytopenias (ITs) are a heterogeneous group of syndromic and nonsyndromic diseases caused by mutations affecting different genes. Alterations of ACTN1, the gene encoding for α-actinin 1, have recently been identified in a few families as being responsible for a mild form of IT (ACTN1-related thrombocytopenia; ACTN1-RT). To better characterize this disease, we screened ACTN1 in 128 probands and found 10 (8 novel) missense heterozygous variants in 11 families. Combining bioinformatics, segregation, and functional studies, we demonstrated that all but 1 amino acid substitution had deleterious effects. The clinical and laboratory findings of 31 affected individuals confirmed that ACTN1-RT is a mild macrothrombocytopenia with low risk for bleeding. Low reticulated platelet counts and only slightly increased serum thrombopoietin levels indicated that the latest phases of megakaryopoiesis were affected. Given its relatively high frequency in our cohort (4.2\%), ACTN1-RT has to be taken into consideration in the differential diagnosis of ITs.

}, keywords = {Actinin, Adolescent, Adult, Aged, Aged, 80 and over, Blood Platelets, Case-Control Studies, Child, Child, Preschool, Female, Gene Expression, Genotype, Heterozygote, Humans, Male, Middle Aged, Mutation, Missense, Pedigree, Phenotype, Platelet Count, Severity of Illness Index, Thrombocytopenia, Thrombopoiesis, Thrombopoietin}, issn = {1528-0020}, doi = {10.1182/blood-2014-08-594531}, author = {Bottega, Roberta and Marconi, Caterina and Faleschini, Michela and Baj, Gabriele and Cagioni, Claudia and Pecci, Alessandro and Pippucci, Tommaso and Ramenghi, Ugo and Pardini, Simonetta and Ngu, Loretta and Baronci, Carlo and Kunishima, Shinji and Balduini, Carlo L and Seri, Marco and Savoia, Anna and Noris, Patrizia} } @article {7698, title = {Clinical aspects of Fanconi anemia individuals with the same mutation of FANCF identified by next generation sequencing.}, journal = {Birth Defects Res A Clin Mol Teratol}, volume = {103}, year = {2015}, month = {2015 Dec}, pages = {1003-1010}, abstract = {

BACKGROUND: Fanconi anemia (FA) is a rare genetic disease characterized by congenital malformations, aplastic anemia and increased risk of developing malignancies. FA is genetically heterogeneous as it is caused by at least 17 different genes. Among these, FANCA, FANCC, and FANCG account for approximately 85\% of the patients whereas the remaining genes are mutated in only a small percentage of cases. For this reason, the molecular diagnostic process is complex and not always extended to all the FA genes, preventing the characterization of individuals belonging to rare groups.

METHODS: The FA genes were analyzed using a next generation sequencing approach in two unrelated families.

RESULTS: The analysis identified the same, c.484_485del, homozygous mutation of FANCF in both families. A careful examination of three electively aborted fetuses in one family and one affected girl in the other indicated an association of the FANCF loss-of-function mutation with a severe phenotype characterized by multiple malformations.

CONCLUSION: The systematic use of next generation sequencing will allow the recognition of individuals from rare complementation groups, a better definition of their clinical phenotypes, and consequently, an appropriate genetic counseling. Birth Defects Research (Part A) 103:1003-1010, 2015. {\textcopyright} 2015 Wiley Periodicals, Inc.

}, issn = {1542-0760}, doi = {10.1002/bdra.23388}, author = {Nicchia, Elena and Benedicenti, Francesco and Rocco, Daniela De and Greco, Chiara and Bottega, Roberta and Inzana, Francesca and Faleschini, Michela and Bonin, Serena and Cappelli, Enrico and Mogni, Massimo and Stanzial, Franco and Svahn, Johanna and Dufour, Carlo and Savoia, Anna} } @article {3554, title = {Analysis of 339 pregnancies in 181 women with 13 different forms of inherited thrombocytopenia.}, journal = {Haematologica}, volume = {99}, year = {2014}, month = {2014 Aug}, pages = {1387-94}, abstract = {

Pregnancy in women with inherited thrombocytopenias is a major matter of concern as both the mothers and the newborns are potentially at risk of bleeding. However, medical management of this condition cannot be based on evidence because of the lack of consistent information in the literature. To advance knowledge on this matter, we performed a multicentric, retrospective study evaluating 339 pregnancies in 181 women with 13 different forms of inherited thrombocytopenia. Neither the degree of thrombocytopenia nor the severity of bleeding tendency worsened during pregnancy and the course of pregnancy did not differ from that of healthy subjects in terms of miscarriages, fetal bleeding and pre-term births. The degree of thrombocytopenia in the babies was similar to that in the mother. Only 7 of 156 affected newborns had delivery-related bleeding, but 2 of them died of cerebral hemorrhage. The frequency of delivery-related maternal bleeding ranged from 6.8\% to 14.2\% depending on the definition of abnormal blood loss, suggesting that the risk of abnormal blood loss was increased with respect to the general population. However, no mother died or had to undergo hysterectomy to arrest bleeding. The search for parameters predicting delivery-related bleeding in the mother suggested that hemorrhages requiring blood transfusion were more frequent in women with history of severe bleedings before pregnancy and with platelet count at delivery below 50 {\texttimes} 10(9)/L.

}, keywords = {Adult, Female, Humans, Infant, Newborn, Pregnancy, Pregnancy Complications, Hematologic, Retrospective Studies, Thrombocytopenia, Young Adult}, issn = {1592-8721}, doi = {10.3324/haematol.2014.105924}, author = {Noris, Patrizia and Schlegel, Nicole and Klersy, Catherine and Heller, Paula G and Civaschi, Elisa and Pujol-Moix, N{\'u}ria and Fabris, Fabrizio and Favier, R{\'e}mi and Gresele, Paolo and Latger-Cannard, V{\'e}ronique and Cuker, Adam and Nurden, Paquita and Greinacher, Andreas and Cattaneo, Marco and De Candia, Erica and Pecci, Alessandro and Hurtaud-Roux, Marie-Fran{\c c}oise and Glembotsky, Ana C and Mu{\~n}iz-Diaz, Eduardo and Randi, Maria Luigia and Trillot, Nathalie and Bury, Loredana and Lecompte, Thomas and Marconi, Caterina and Savoia, Anna and Balduini, Carlo L and Bayart, Sophie and Bauters, Anne and Benabdallah-Guedira, Sch{\'e}h{\'e}razade and Boehlen, Fran{\c c}oise and Borg, Jeanne-Yvonne and Bottega, Roberta and Bussel, James and De Rocco, Daniela and de Maistre, Emmanuel and Faleschini, Michela and Falcinelli, Emanuela and Ferrari, Silvia and Ferster, Alina and Fierro, Tiziana and Fleury, Dominique and Fontana, Pierre and James, Chlo{\'e} and Lanza, Francois and Le Cam Duchez, V{\'e}ronique and Loffredo, Giuseppe and Magini, Pamela and Martin-Coignard, Dominique and Menard, Fanny and Mercier, Sandra and Mezzasoma, Annamaria and Minuz, Pietro and Nichele, Ilaria and Notarangelo, Lucia D and Pippucci, Tommaso and Podda, Gian Marco and Pouymayou, Catherine and Rigouzzo, Agnes and Royer, Bruno and Sie, Pierre and Siguret, Virginie and Trichet, Catherine and Tucci, Alessandra and Saposnik, B{\'e}atrice and Veneri, Dino} }