@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 = {<p>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.</p>},
	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}
}
