[Monogenic variants in Laccase domain-containing 1 (LACC1) as the cause of juvenile arthritis]. / Monogene Varianten in "laccase domain-containing 1" (LACC1) als Ursache einer juvenilen Arthritis.

Monogenic mutations in laccase domain-containing 1 (LACC1) are associated with clinical pictures that mimic severe courses of polyarticular or systemic juvenile idiopathic arthritis. The diseases are characterized by an early onset during the first year of life, a familial clustering and a high inflammatory activity. The courses are mostly difficult to influence and often lead to sequelae. In this article four cases from two families are presented in which the homozygous mutation p.T276fs* in LACC1 was detected. The children initially suffered from polyarticular or systemic forms of juvenile arthritis. Of the patients two are currently being treated with tocilizumab and methotrexate and one female patient without a basis treatment is currently only receiving local repeated intra-articular steroids. A fourth female patient underwent an allogeneic bone marrow transplantation due to a relapse of an acute lymphatic leukemia. Since then, no further inflammatory symptoms have occurred. The cases presented are compared with the other 50 courses published to date. In addition, recent studies investigating the influence of LACC1 mutations, particularly on macrophage function, are summarized.

Familial Mediterranean fever in children and adolescents: factors for colchicine dosage and predicting parameters for dose increase.

Objectives: The aim was to analyse factors influencing the individual colchicine dose in children with FMF, to evaluate the impact of dose adjustment on the clinical course and inflammation and to identify clinical parameters and biomarkers that predict dose increase in the near future. Methods: Data from 409 paediatric FMF patients (4566 visits) derived from the national auto-inflammatory diseases registry were analysed. Serum concentrations of S100 molecules were determined by ELISA. Results: The age-dependent colchicine dose is influenced by the present genotype. The body surface area is the anthropometric parameter that correlates best with the applied dosages. Colchicine introduction and dose increase lead to significant reduction of clinical symptoms and inflammation. During established colchicine therapy, an increase of one single biomarker increases the likelihood of a dose increment in the next 12 months with a factor of 1.62-1.94. A combination of biomarkers including S100 molecules increases this odds ratio up to 4.66 when analysing all patients and up to 7.27 when analysing patients with a high risk of severe disease. Conclusion: Colchicine therapy is currently guided mainly by the occurrence of clinical symptoms and serological inflammation. Other factors, such as the genotype, the body surface area and biomarkers, will help to manage colchicine therapy in a more individualized fashion. The additional analysis of S100 molecules as sensitive biomarkers will help to identify patients at risk for dose increases in the near future.