Students' willingness to communicate in the foreign language learning classroom: Exploring the roles of classroom support and psychological needs satisfaction.

Mutations in the gene are responsible for Becker muscular dystrophy (BMD) along with other interrelated allelic dystrophinopathies including Duchenne muscular dystrophy (DMD) and X-linked dilated cardiomyopathy (XLDCM). The dystrophin protein, encoded by the gene on the X chromosome, has functions in smooth and skeletal muscle and cognitive function. The large size of the gene (79 exons over 2.2 Mb of DNA) renders it prone to mutations (inherited or sporadic []), namely single or multiple exon deletions or duplications, and point mutations. Mutations are either in-frame or out-of-frame. Out-of-frame mutations result in a malfunctioning, prematurely truncated protein. In the majority of cases, in-frame mutations preserve the reading frame, resulting in decreased levels of, or partially functional, truncated dystrophin protein. This principle is referred to as the reading frame rule; however, exceptions have been documented. Specifically, some in-frame mutations can result in a severe DMD phenotype, whereas certain out-of-frame mutations may lead to a milder, BMD-like presentation. Most cases of DMD are caused by out-of-frame mutations, while the majority of BMD cases are caused by in-frame mutations. Becker muscular dystrophy is considered a rare disease with a reported global prevalence estimated at 1.6 per 100,000 people. The clinical course of BMD is highly heterogenous, making disease trajectory difficult to predict due to variations in the age at disease onset and clinical presentation. Clinical manifestations commonly include muscle weakness and cardiac dysfunction; however, loss of ambulation, loss of upper limb function, pulmonary decline, and premature death may also occur. Cognitive disability may also be present yet is considered non-progressive. More severe symptoms typically manifest in male patients, while female carriers may exhibit relatively mild skeletal muscle weakness and dilated cardiomyopathy. Among allelic dystrophinopathies, DMD, the most severe of the diseases, typically presents with weakness beginning in early childhood; without treatment, affected individuals are usually wheelchair bound by age 12 and often die from cardiac or respiratory complications in their early twenties. Another of the dystrophinopathies, XLDCM, primarily affects the heart, causing severe cardiac involvement with minimal skeletal muscle symptoms and often leading to heart failure in adolescence. In contrast, BMD generally has a later onset and slower progression than DMD, though severity can range from asymptomatic to severe and cardiac involvement or cardiomyopathy may occur at any age or not at all.