@article {10549, title = {ADA2 deficiency (DADA2) as an unrecognised cause of early onset polyarteritis nodosa and stroke: a multicentre national study.}, journal = {Ann Rheum Dis}, volume = {76}, year = {2017}, month = {2017 Oct}, pages = {1648-1656}, abstract = {

OBJECTIVES: To analyse the prevalence of mutations in patients diagnosed with early onset livedo reticularis and/or haemorrhagic/ischaemic strokes in the context of inflammation or polyarteritis nodosa (PAN). Forty-eight patients from 43 families were included in the study.

METHODS: Direct sequencing of was performed by Sanger analysis. Adenosine deaminase 2 (ADA2) enzymatic activity was analysed in monocyte isolated from patients and healthy controls incubated with adenosine and with or without an ADA1 inhibitor.

RESULTS: Biallelic homozygous or compound heterozygous mutations were detected in 15/48 patients. A heterozygous disease-associated mutation (p.G47V) was observed in two affected brothers. The mean age of onset of the genetically positive patients was 24 months (6 months to 7 years). Ten patients displayed one or more cerebral strokes during their disease course. Low immunoglobulin levels were detected in six patients. Thalidomide and anti-TNF (tumour necrosis factor) blockers were the most effective drugs. Patients without mutations had a later age at disease onset, a lower prevalence of neurological and skin manifestations; one of these patients displayed all the clinical features of adenosine deaminase 2deficiency (DADA2) and a defective enzymatic activity suggesting the presence of a missed mutation or a synthesis defect.

CONCLUSIONS: DADA2 accounts for paediatric patients diagnosed with PAN-like disease and strokes and might explain an unrecognised condition in patients followed by adult rheumatologist. Timely diagnosis and treatment with anti-TNF agents are crucial for the prevention of severe complications of the disease. Functional assay to measure ADA2 activity should complement genetic testing in patients with non-confirming genotypes.

}, keywords = {Adenosine Deaminase, Adolescent, Age of Onset, Case-Control Studies, Child, Child, Preschool, DNA Mutational Analysis, Female, Heterozygote, Homozygote, Humans, Immunoglobulins, Immunosuppressive Agents, Infant, Intercellular Signaling Peptides and Proteins, Italy, Livedo Reticularis, Male, Pedigree, Polyarteritis Nodosa, Stroke, Thalidomide, Tumor Necrosis Factor-alpha, Young Adult}, issn = {1468-2060}, doi = {10.1136/annrheumdis-2016-210802}, author = {Caorsi, Roberta and Penco, Federica and Grossi, Alice and Insalaco, Antonella and Omenetti, Alessia and Alessio, Maria and Conti, Giovanni and Marchetti, Federico and Picco, Paolo and Tommasini, Alberto and Martino, Silvana and Malattia, Clara and Gallizi, Romina and Podda, Rosa Anna and Salis, Annalisa and Falcini, Fernanda and Schena, Francesca and Garbarino, Francesca and Morreale, Alessia and Pardeo, Manuela and Ventrici, Claudia and Passarelli, Chiara and Zhou, Qing and Severino, Mariasavina and Gandolfo, Carlo and Damonte, Gianluca and Martini, Alberto and Ravelli, Angelo and Aksentijevich, Ivona and Ceccherini, Isabella and Gattorno, Marco} } @article {1824, title = {High incidence of NLRP3 somatic mosaicism in patients with chronic infantile neurologic, cutaneous, articular syndrome: results of an International Multicenter Collaborative Study.}, journal = {Arthritis Rheum}, volume = {63}, year = {2011}, month = {2011 Nov}, pages = {3625-32}, abstract = {

OBJECTIVE: Chronic infantile neurologic, cutaneous, articular (CINCA) syndrome, also known as neonatal-onset multisystem inflammatory disease (NOMID), is a dominantly inherited systemic autoinflammatory disease. Although heterozygous germline gain-of-function NLRP3 mutations are a known cause of this disease, conventional genetic analyses fail to detect disease-causing mutations in \~{}40\% of patients. Since somatic NLRP3 mosaicism has been detected in several mutation-negative NOMID/CINCA syndrome patients, we undertook this study to determine the precise contribution of somatic NLRP3 mosaicism to the etiology of NOMID/CINCA syndrome.

METHODS: An international case-control study was performed to detect somatic NLRP3 mosaicism in NOMID/CINCA syndrome patients who had shown no mutation during conventional sequencing. Subcloning and sequencing of NLRP3 was performed in these mutation-negative NOMID/CINCA syndrome patients and their healthy relatives. Clinical features were analyzed to identify potential genotype-phenotype associations.

RESULTS: Somatic NLRP3 mosaicism was identified in 18 of the 26 patients (69.2\%). Estimates of the level of mosaicism ranged from 4.2\% to 35.8\% (mean {\textpm} SD 12.1 {\textpm} 7.9\%). Mosaicism was not detected in any of the 19 healthy relatives (18 of 26 patients versus 0 of 19 relatives; P < 0.0001). In vitro functional assays indicated that the detected somatic NLRP3 mutations had disease-causing functional effects. No differences in NLRP3 mosaicism were detected between different cell lineages. Among nondescript clinical features, a lower incidence of mental retardation was noted in patients with somatic mosaicism. Genotype-matched comparison confirmed that patients with somatic NLRP3 mosaicism presented with milder neurologic symptoms.

CONCLUSION: Somatic NLRP3 mutations were identified in 69.2\% of patients with mutation-negative NOMID/CINCA syndrome. This indicates that somatic NLRP3 mosaicism is a major cause of NOMID/CINCA syndrome.

}, keywords = {Adolescent, Adult, Carrier Proteins, Case-Control Studies, Child, Child, Preschool, Cryopyrin-Associated Periodic Syndromes, Female, Genetic Association Studies, Humans, Infant, Male, Mosaicism}, issn = {1529-0131}, doi = {10.1002/art.30512}, author = {Tanaka, Naoko and Izawa, Kazushi and Saito, Megumu K and Sakuma, Mio and Oshima, Koichi and Ohara, Osamu and Nishikomori, Ryuta and Morimoto, Takeshi and Kambe, Naotomo and Goldbach-Mansky, Raphaela and Aksentijevich, Ivona and de Saint Basile, Genevi{\`e}ve and Neven, B{\'e}n{\'e}dicte and van Gijn, Mari{\"e}lle and Frenkel, Joost and Ar{\'o}stegui, Juan I and Yag{\"u}e, Jordi and Merino, Rosa and Iba{\~n}ez, Mercedes and Pontillo, Alessandra and Takada, Hidetoshi and Imagawa, Tomoyuki and Kawai, Tomoki and Yasumi, Takahiro and Nakahata, Tatsutoshi and Heike, Toshio} }