[The transitional care from pediatrics to adult medicine within the rare autoimmune and autoinflammatory diseases network].

The committee involved in transitional care within the French network on rare autoimmune and auto-inflammatory diseases has developed tools and published recommendations for the care during the transition of adolescents and young adults suffering from these chronic diseases which often demonstrate flares. As the challenge is the compliance to the continuation of care in the adult world, the therapeutic alliance between the young patient and his/her pediatrician and then his/her adult doctor is particularly important. The working group thus carried out a survey on how doctors and young patients perceive their relationship during the period of transition in medical supervision.

Development of a Prediction Model for COVID-19 Acute Respiratory Distress Syndrome in Patients With Rheumatic Diseases: Results From the Global Rheumatology Alliance Registry.

Objective: Some patients with rheumatic diseases might be at higher risk for coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS). We aimed to develop a prediction model for COVID-19 ARDS in this population and to create a simple risk score calculator for use in clinical settings.

Methods: Data were derived from the COVID-19 Global Rheumatology Alliance Registry from March 24, 2020, to May 12, 2021.

[Transition from pediatric to adult care: Recommendations of the French network for autoimmune and autoinflammatory diseases (FAIR)].

Autoimmune and autoinflammatory diseases (AIDs) are a heterogeneous group of diseases. They can occur in childhood and account for significant morbidity and mortality. Transitioning from pediatric to adult healthcare can be difficult for patients and their families.

Alteration of sarcoplasmic reticulum ca release in skeletal muscle from calpain 3-deficient mice.

Mutations of Ca(2+)-activated proteases (calpains) cause muscular dystrophies. Nevertheless, the specific role of calpains in Ca(2+) signalling during the onset of dystrophies remains unclear. We investigated Ca(2+) handling in skeletal cells from calpain 3-deficient mice.

Abnormal distribution of calcium-handling proteins: a novel distinctive marker in core myopathies.

Central core disease (CCD) and multi-minicore disease (MmD) are muscle disorders characterized by foci of mitochondria depletion and sarcomere disorganization ("cores") in muscle fibers. Although core myopathies are the most frequent congenital myopathies, their pathogenesis remains elusive and specific diagnostic markers are lacking. Core myopathies are mostly caused by mutations in 2 sarcoplasmic reticulum proteins: the massive Ca-release channel RyR1 or the selenoprotein N (SelN) of unknown function.

Muscle imaging in dominant core myopathies linked or unlinked to the ryanodine receptor 1 gene.

Objective: To characterize the muscle involvement of patients with central core disease (CCD) caused by mutations in the ryanodine receptor 1 gene (RYR1) and to compare these findings with those from patients with core myopathies unlinked to the RYR1 gene.

Methods: We performed a systematic muscular imaging assessment in 11 patients with an RYR1 gene mutation and compared these findings with those of 5 patients from two unrelated families with autosomal dominant core myopathies not linked to RYR1, ACTA1, or MYH7 gene loci.

Results: All patients with RYR1 CCD had a characteristic pattern with predominant involvement of the gluteus maximus, adductor magnus, sartorius, vastus intermediolateralis, soleus, and lateral gastrocnemius muscles.

Characterization of the muscle involvement in dynamin 2-related centronuclear myopathy.

Centronuclear myopathy (CNM) is a slowly progressive congenital myopathy characterized by abnormal centrally located nuclei in a large number of muscle fibres. Recently, different missense mutations affecting the middle domain of the dynamin 2 (DNM2) have been shown to cause autosomal dominant CNM. In order to better define the phenotype of DNM2-related CNM, we report here on the clinical and muscle imaging findings of 10 patients harbouring DNM2 mutations.

Clinical and histopathological aspects of central core disease associated and non-associated with RYR1 locus.

We analysed the clinical, histochemical, ultrastructural and genetic data of patients affected by central core disease (CCD) studied during the last 20 years. From a total series of 86 CCD-families, we have identified 46 CCD families with RYR1 mutations (16 autosomal dominant, 8 autosomal recessive, 17 sporadic cases and 5 de novo mutations). Out of the other 40 CCD families, the RyR1 gene was entirely excluded in 7 families, by cDNA sequencing or linkage analysis, indicating a genetic heterogeneity of CCD.

Severe hypophosphatasia: characterization of fifteen novel mutations in the ALPL gene.

Hypophosphatasia is an inherited disorder characterized by defective bone mineralization and deficiency of serum and tissue liver/bone/kidney alkaline phosphatase (L/B/K ALP) activity. We report the characterization of ALPL gene mutations in a series of 11 families from various origins affected by perinatal and infantile hypophosphatasia. Sixteen distinct mutations were found, fifteen of them not previously reported: M45V, G46R, 388-391delGTAA, 389delT, T131I, G145S, D172E, 662delG, G203A, R255L, 876-881delAGGGGA, 962delG, E294K, E435K, and A451T.

Evidence of a founder effect for the tissue-nonspecific alkaline phosphatase (TNSALP) gene E174K mutation in hypophosphatasia patients.

Hypophosphatasia is a rare inborn error of metabolism characterised by defective bone mineralisation caused by a deficiency of liver-, bone- or kidney-type alkaline phosphatase due to mutations in the tissue-nonspecific alkaline phosphatase (TNSALP) gene. The clinical expression of the disease is highly variable, ranging from stillbirth with a poorly mineralised skeleton to pathologic skeletal fractures which develop in late adulthood only. This clinical heterogeneity is due to the strong allelic heterogeneity in the TNSALP gene.

Stable expression of calpain 3 from a muscle transgene in vivo: immature muscle in transgenic mice suggests a role for calpain 3 in muscle maturation.

Limb-girdle muscular dystrophy, type 2A (LGMD 2A), is an autosomal recessive disorder that causes late-onset muscle-wasting, and is due to mutations in the muscle-specific protease calpain 3 (C3). Although LGMD 2A would be a feasible candidate for gene therapy, the reported instability of C3 in vitro raised questions about the potential of obtaining a stable, high-level expression of C3 from a transgene in vivo. We have generated transgenic (Tg) mice with muscle-specific overexpression of full-length C3 or C3 isoforms, which arise from alternative splicing, to test whether stable expression of C3 transgenes could occur in vivo.

Calpain 3 mRNA expression in mice after denervation and during muscle regeneration.

Lack of functional calpain 3 in humans is a cause of limb girdle muscular dystrophy, but the function(s) of calpain 3 remain(s) unknown. Special muscle conditions in which calpain 3 is downregulated could yield valuable clues to the understanding of its function(s). We monitored calpain 3 mRNA amounts by quantitative RT-PCR and compared them with those of alpha-skeletal actin mRNA in mouse leg muscles for different types of denervation and muscle injury.

Loss of calpain 3 proteolytic activity leads to muscular dystrophy and to apoptosis-associated IkappaBalpha/nuclear factor kappaB pathway perturbation in mice.

Calpain 3 is known as the skeletal muscle-specific member of the calpains, a family of intracellular nonlysosomal cysteine proteases. It was previously shown that defects in the human calpain 3 gene are responsible for limb girdle muscular dystrophy type 2A (LGMD2A), an inherited disease affecting predominantly the proximal limb muscles. To better understand the function of calpain 3 and the pathophysiological mechanisms of LGMD2A and also to develop an adequate model for therapy research, we generated capn3-deficient mice by gene targeting.

Human-mouse differences in the embryonic expression patterns of developmental control genes and disease genes.

Our understanding of early human development has been impeded by the general difficulty in obtaining suitable samples for study. As a result, and because of the extraordinarily high degree of evolutionary conservation of many developmentally important genes and developmental pathways, great reliance has been placed on extrapolation from animal models of development, principally the mouse. However, the strong evolutionary conservation of coding sequence for developmentally important genes does not necessarily mean that their expression patterns are as highly conserved.

Expression and functional characteristics of calpain 3 isoforms generated through tissue-specific transcriptional and posttranscriptional events.

Calpain 3 is a nonlysosomal cysteine protease whose biological functions remain unknown. We previously demonstrated that this protease is altered in limb girdle muscular dystrophy type 2A patients. Preliminary observations suggested that its gene is subjected to alternative splicing.