Fine mapping and conditional analysis identify a new mutation in the autoimmunity susceptibility gene BLK that leads to reduced half-life of the BLK protein

OBJECTIVES: To perform fine mapping of the autoimmunity susceptibility gene BLK and identify functional variants involved in systemic lupus erythematosus (SLE). METHODS: Genotyping of 1163 European SLE patients and 1482 controls and imputation were performed covering the BLK gene with 158 single-nucleotide polymorphisms. Logistic regression analysis was done using PLINK and conditional analyses using GENABEL's test score. Transfections of BLK constructs on HEK293 cells containing the novel mutation or the wild type form were analysed for their effect on protein half-life using a protein stability assay, cycloheximide and western blot. CHiP-qPCR for detection of nuclear factor κ B (NFkB) binding. RESULTS: Fine mapping of BLK identified two independent genetic effects with functional consequences: one represented by two tightly linked associated haplotype blocks significantly enriched for NFκB-binding sites and numerous putative regulatory variants whose risk alleles correlated with low BLK mRNA levels. Binding of NFkBp50 and p65 to an associated 1.2 Kb haplotype segment was confirmed. A second independent genetic effect was represented by an Ala71Thr, low-frequency missense substitution with an OR=2.31 (95% CI 1.38 to 3.86). The 71Thr decreased BLK protein half-life. CONCLUSIONS: These results show that rare and common regulatory variants in BLK are involved in disease susceptibility and both, albeit independently, lead to reduced levels of BLK protein

Effects of ATLAS 2030 gait exoskeleton on strength and range of motion in children with spinal muscular atrophy II: a case series

Abstract Background Children with spinal muscular atrophy (SMA) present muscle weakness and atrophy that results in a number of complications affecting their mobility, hindering their independence and the development of activities of daily living. Walking has well-recognized physiological and functional benefits. The ATLAS 2030 exoskeleton is a paediatric device that allows gait rehabilitation in children with either neurological or neuromuscular pathologies with gait disorders. The purpose is to assess the effects in range of motion (ROM) and maximal isometric strength in hips, knees and ankles of children with SMA type II after the use of ATLAS 2030 exoskeleton. Methods Three children (mean age 5.7 ± 0.6) received nine sessions bi-weekly of 60 min with ATLAS 2030. ROM was assessed by goniometry and strength by hand-held dynamometer. All modes of use of the exoskeleton were tested: stand up and sit down, forward and backward walking, and gait in automatic and active-assisted modes. In addition, different activities were performed during the gait session. A descriptive analysis of all variables was carried out. Results The average time of use was 53.5 ± 12.0 min in all sessions, and all participants were able to carry out all the proposed activities as well as to complete the study. Regarding isometric strength, all the measurements increased compared to the initial state, obtaining the greatest improvements for the hip flexors (60.2%) and extensors muscles (48.0%). The ROM increased 12.6% in hip and 34.1% in the ankle after the study, while knee ROM remained stable after the study. Conclusion Improvements were showed in ROM and maximal isometric strength in hips, knees and ankles after using ATLAS 2030 paediatric gait exoskeleton in all three children. This research could serve as a preliminary support for future clinical integration of ATLAS 2030 as a part of a long-term rehabilitation of children with SMA. Trial registration: The approval was obtained (reference 47/370329.9/19) by Comunidad de Madrid Regional Research Ethics Committee with Medical Products and the clinical trial has been registered on Clinical Trials.gov: NCT04837157