Biallelic loss-of-function LACC1/FAMIN Mutations Presenting as Rheumatoid Factor-Negative Polyarticular Juvenile Idiopathic Arthritis

Juvenile idiopathic arthritis (JIA) is a complex rheumatic disease with both autoimmune and autoinflammatory components. Recently, familial cases of systemic-onset JIA have been attributed to mutations in LACC1/FAMIN. We describe three affected siblings from a Moroccan consanguineous family with an early-onset chronic, symmetric and erosive arthritis previously diagnosed as rheumatoid factor (RF)-negative polyarticular JIA. Autozygosity mapping identified four homozygous regions shared by all patients, located in chromosomes 3, 6 (n:2) and 13, containing over 330 genes. Subsequent whole exome sequencing identified two potential candidate variants within these regions (in FARS2 and LACC1/FAMIN). Genotyping of a cohort of healthy Moroccan individuals (n: 352) and bioinformatics analyses finally supported the frameshift c.128_129delGT mutation in the LACC1/FAMIN gene, leading to a truncated protein (p.Cys43Tyrfs*6), as the most probable causative gene defect. Additional targeted sequencing studies performed in patients with systemic-onset JIA (n:23) and RF-negative polyarticular JIA (n: 44) revealed no pathogenic LACC1/FAMIN mutations. Our findings support the homozygous genotype in the LACC1/FAMIN gene as the defect underlying the family here described with a recessively inherited severe inflammatory joint disease. Our evidences provide further support to the involvement of LACC1/FAMIN deficiency in different types of JIA in addition to the initially described systemic-onset JIA.

Bibliographic Details

Main Authors:	Rabionet, Raquel, Remesal, Agustín, Mensa-Vilaró, Anna, Murías, Sara, Alcobendas, Rosa, González-Roca, Eva, Ruiz-Ortiz, Estibaliz, Antón, Jordi, Iglesias, Estibaliz, Modesto, Consuelo, Comas, David, Puig, Anna, Drechsel, Oliver, Ossowski, Stephan, Yagüe, Jordi, Merino, Rosa, Estivill, Xavier, Arostegui, Juan Ignacio
Other Authors:	Generalitat de Catalunya
Format:	artículo biblioteca
Published:	Springer Nature 2019-03-14
Online Access:	http://hdl.handle.net/10261/207871 http://dx.doi.org/10.13039/501100004587 http://dx.doi.org/10.13039/501100002809 http://dx.doi.org/10.13039/501100000780 http://dx.doi.org/10.13039/501100003329
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