Almost all multi-exon genes will produce incorrectly spliced transcripts but the frequency of this background noise will depend on the size of the genes, the number of introns, and the quality of the splice site sequences.In some cases, splice variants will be produced by mutations in the gene (DNA). These can be SNP polymorphisms that create a cryptic splice site or mutate a functional site. They can also be somatic cell mutations that affect splicing in a particular tissue or a cell line. When the mutant allele is in a heterozygous state this will result in production of two abundant splice variants; one functional and one non-functional. In the homozygous state the mutant alleles may cause a genetic disease such as the hemophilia found in descendants of Queen Victoria where a mutation in one of the introns in a blood clotting factor gene creates a cryptic 3 splice site resulting in aberrant splicing. A significant fraction of human deaths by disease may be caused by mutations that interfere with normal splicing; mostly by creating cryptic splice sites.Incorrectly spliced transcripts can easily be detected and their sequences entered into the online databases. They are usually described as "alternatively spliced" transcripts, which can be confusing because the term does not distinguish between real, biologically relevant, alternative splicing and processing noise due to splicing errors. One of the central issues in the field of alternative splicing is working out the differences between these two possibilities.
Cutaneous actinomycosis is a chronic disease that affects the deep subcutaneous tissue of the skin. Caused by an anaerobic, Gram-positive, filamentous type of bacteria in the genus Actinomyces,: 270  invasion of the soft tissue leads to the formation of abnormal channels leading to the skin surface (external sinus tracts) that discharge pale yellow sulfur granules.This disease is uncommon, and has non-specific clinical features, making it difficult to diagnose.Cervicofacial, pulmonary/thoracic and gastrointestinal forms exist, yet cervicofacial disease accounts for two-thirds of reported infections. See also
Skin lesion


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