Related Research Articles
Muscular dystrophies (MD) are a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Some types are also associated with problems in other organs.
A microsatellite is a tract of repetitive DNA in which certain DNA motifs are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. They have a higher mutation rate than other areas of DNA leading to high genetic diversity. Microsatellites are often referred to as short tandem repeats (STRs) by forensic geneticists and in genetic genealogy, or as simple sequence repeats (SSRs) by plant geneticists.
Limb–girdle muscular dystrophy (LGMD) is a genetically heterogeneous group of rare muscular dystrophies that share a set of clinical characteristics. It is characterised by progressive muscle wasting which affects predominantly hip and shoulder muscles. LGMD usually has an autosomal pattern of inheritance. It currently has no known cure or treatment.
Repeated sequences are short or long patterns of nucleic acids that occur in multiple copies throughout the genome. In many organisms, a significant fraction of the genomic DNA is repetitive, with over two-thirds of the sequence consisting of repetitive elements in humans. Some of these repeated sequences are necessary for maintaining important genome structures such as telomeres or centromeres.
Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy that primarily affects boys. Muscle weakness usually begins around the age of four, and worsens quickly. Muscle loss typically occurs first in the thighs and pelvis followed by the arms. This can result in trouble standing up. Most are unable to walk by the age of 12. Affected muscles may look larger due to increased fat content. Scoliosis is also common. Some may have intellectual disability. Females with a single copy of the defective gene may show mild symptoms.
Facioscapulohumeral muscular dystrophy (FSHD) is a type of muscular dystrophy, a group of heritable diseases that cause degeneration of muscle and progressive weakness. Per the name, FSHD tends to sequentially weaken the muscles of the face, those that position the scapula, and those overlying the humerus bone of the upper arm. These areas can be spared, and muscles of other areas usually are affected, especially those of the chest, abdomen, spine, and shin. Almost any skeletal muscle can be affected in advanced disease. Abnormally positioned, termed 'winged', scapulas are common, as is the inability to lift the foot, known as foot drop. The two sides of the body are often affected unequally. Weakness typically manifests at ages 15 – 30 years. FSHD can also cause hearing loss and blood vessel abnormalities at the back of the eye.
Subtelomeres are segments of DNA between telomeric caps and chromatin.
Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics.
Emery–Dreifuss muscular dystrophy (EDMD) is a type of muscular dystrophy, a group of heritable diseases that cause progressive impairment of muscles. EDMD affects muscles used for movement, causing atrophy, weakness and contractures. It almost always affects the heart, causing abnormal rhythms, heart failure, or sudden cardiac death. It is rare, affecting 0.39 per 100,000 people. It is named after Alan Eglin H. Emery and Fritz E. Dreifuss.
A trinucleotide repeat expansion, also known as a triplet repeat expansion, is the DNA mutation responsible for causing any type of disorder categorized as a trinucleotide repeat disorder. These are labelled in dynamical genetics as dynamic mutations. Triplet expansion is caused by slippage during DNA replication, also known as "copy choice" DNA replication. Due to the repetitive nature of the DNA sequence in these regions, 'loop out' structures may form during DNA replication while maintaining complementary base pairing between the parent strand and daughter strand being synthesized. If the loop out structure is formed from the sequence on the daughter strand this will result in an increase in the number of repeats. However, if the loop out structure is formed on the parent strand, a decrease in the number of repeats occurs. It appears that expansion of these repeats is more common than reduction. Generally, the larger the expansion the more likely they are to cause disease or increase the severity of disease. Other proposed mechanisms for expansion and reduction involve the interaction of RNA and DNA molecules.
Emerin is a protein that in humans is encoded by the EMD gene, also known as the STA gene. Emerin, together with LEMD3, is a LEM domain-containing integral protein of the inner nuclear membrane in vertebrates. Emerin is highly expressed in cardiac and skeletal muscle. In cardiac muscle, emerin localizes to adherens junctions within intercalated discs where it appears to function in mechanotransduction of cellular strain and in beta-catenin signaling. Mutations in emerin cause X-linked recessive Emery–Dreifuss muscular dystrophy, cardiac conduction abnormalities and dilated cardiomyopathy.
Gamma-sarcoglycan is a protein that in humans is encoded by the SGCG gene. The α to δ-sarcoglycans are expressed predominantly (β) or exclusively in striated muscle. A mutation in any of the sarcoglycan genes may lead to a secondary deficiency of the other sarcoglycan proteins, presumably due to destabilisation of the sarcoglycan complex. The disease-causing mutations in the α to δ genes cause disruptions within the dystrophin-associated protein (DAP) complex in the muscle cell membrane. The transmembrane components of the DAP complex link the cytoskeleton to the extracellular matrix in adult muscle fibres, and are essential for the preservation of the integrity of the muscle cell membrane.
Ligand-dependent nuclear receptor-interacting factor 1 (LRIF1) also known as receptor-interacting factor 1 (RIF1) is a protein that in humans is encoded by the LRIF1 gene.
Tripartite motif-containing protein 32 is a protein that in humans is encoded by the TRIM32 gene. Since its discovery in 1995, TRIM32 has been shown to be implicated in a number of diverse biological pathways.
Protein FRG1 is an actin-bundling protein that in humans is encoded by the FRG1 gene.
Double homeobox, 4 also known as DUX4 is a protein which in humans is encoded by the DUX4 gene. Its misexpression is the cause of facioscapulohumeral muscular dystrophy (FSHD).
Breakage-fusion-bridge (BFB) cycle is a mechanism of chromosomal instability, discovered by Barbara McClintock in the late 1930s.
Nicola Jane Royle is a British geneticist who heads the Telomere Research Group in the Department of Genetics and Genome Biology at the University of Leicester. She is a specialist in the cellular processes that affect the stability of telomeres, the essential DNA-protein structures that cap the ends of chromosomes and play significant roles in cancer and ageing.
DXZ4 is a variable number tandemly repeated DNA sequence. In humans it is composed of 3kb monomers containing a highly conserved CTCF binding site. CTCF is a transcription factor protein and the main insulator responsible for partitioning of chromatin domains in the vertebrate genome.
References
- 1 2 3 Dumbovic, G; Forcales, SV; Perucho, M (3 July 2017). "Emerging roles of macrosatellite repeats in genome organization and disease development". Epigenetics. 12 (7): 515–526. doi:10.1080/15592294.2017.1318235. PMC 5687341 . PMID 28426282.
- ↑ Wagner, Kathryn R. (December 2019). "Facioscapulohumeral Muscular Dystrophies". CONTINUUM: Lifelong Learning in Neurology. 25 (6): 1662–1681. doi:10.1212/CON.0000000000000801. PMID 31794465. S2CID 208531681.
- ↑ Horakova, AH; Moseley, SC; McLaughlin, CR; Tremblay, DC; Chadwick, BP (15 October 2012). "The macrosatellite DXZ4 mediates CTCF-dependent long-range intrachromosomal interactions on the human inactive X chromosome". Human Molecular Genetics. 21 (20): 4367–77. doi:10.1093/hmg/dds270. PMC 3459461 . PMID 22791747.
- ↑ Thoraval, Didier; Asakawa, Jun-ichi; Wimmer, Katharina; Kuick, Rork; Lamb, Barbara; Richardson, Bruce; Ambros, Peter; Glover, Thomas; Hanash, Samir (1996). "Demethylation of repetitive DNA sequences in neuroblastoma". Genes, Chromosomes and Cancer. 17 (4): 234–244. doi:10.1002/(SICI)1098-2264(199612)17:4<234::AID-GCC5>3.0.CO;2-4. ISSN 1098-2264. PMID 8946205. S2CID 30585909.
- ↑ Dumbović, Gabrijela; Biayna, Josep; Banús, Jordi; Samuelsson, Johanna; Roth, Anna; Diederichs, Sven; Alonso, Sergio; Buschbeck, Marcus; Perucho, Manuel; Forcales, Sonia-V (2018-06-20). "A novel long non-coding RNA from NBL2 pericentromeric macrosatellite forms a perinucleolar aggregate structure in colon cancer". Nucleic Acids Research. 46 (11): 5504–5524. doi:10.1093/nar/gky263. ISSN 0305-1048. PMC 6009586 . PMID 29912433.
 | This genetics article is a stub. You can help Wikipedia by expanding it. |