SMA (spinal muscular atrophy) is a disease that robs people of their physical strength by affecting the motor nerve cells in the spinal cord, thereby removing their ability to walk, eat or to breathe. It is the leading genetic cause of death in infants. SMA is caused by a mutation in the survival motor neuron 1 (SMN1) gene. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Spinal muscular atrophy (SMA) types o, 1,2,3 and 4 are inherited because abnormal recessive genetic disorders are associated with abnormalities (mutations) in the SMN1 and SMN2 genes on chromosome 5 at chromosomal locus 5q11-q13. SMA1 is believed to be the main disease caused by genes. Approximately 95 to 98% of affected individuals have deletions in the SMA 1 gene, and 2 to 5% have specific mutations in the SMA 1 genes that result in decreased production of SMN proteins. When three or more copies of the SMA 2 gene are also present, the disease may be milder. Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosome received from the father and mother. Recessive genetic disorders have occurred. when an individual inherits the same abnormal gene or trait from each parent. If a person has received one normal gene and one gene for the disease, they will carry the disease, but usually will not have symptoms. The risk for two carrier parents of both transmitting the defective gene and therefore of having an affected child is 25% with each pregnancy. The risk of having a carrier child like the parents is 50% with each pregnancy. The chance of a child receiving normal genes from both parents and being genetically normal for that particular trait is 25%. The risk is the same for men and women.Biological or surrogate markers for smear tests in development.Keep in mind: this is just a sample.Get a personalized article from our editors now experts.Get a Personalized Assay These potential surrogate markers studied to date include: Measuring the quantity and ratio of full-length and truncated SMN2 RNA transcripts as well as the absence of SMN proteins from white blood cells or fibroblast cultures. Count motor units that showed correlation with SMN 2 copy number, age, and functions. Quantitative ultrasound in the assessment of muscle changes in patients with SMA. Electrical impedance. A longitudinal study of surrogate markers will be necessary before a particular marker can be used in an intervention study..