SMA-Why+Does+it+Happen?

== = = = = = Spinal Muscular Atrophy is a genetic mutation, meaning that something changed in the cells inside a baby, specifically in its chromosomes (genetic information held in our DNA) that gave it the disorder it was born with. SMA is at its most deadly state during the first 18 months of life, after which its severity decreases. The most common mutation that causes SMA happens when the survival motor neuron 1 gene, also called the SMN1 gene, is deleted on chromosome 5 (there are 23 chromosomes in all). This means it is taken out of the list of instructions the DNA has (Medical Ethics: Genetic Testing and Spinal Muscular Atrophy). Both parents can carry this mutation, but it may remain recessive (sleeping, essentially), unless the parents happen to pair the SMA type of chromosome 5 together, which will most likely result in their children having this disorder ( About Spinal Muscular Atrophy). The real problem is in the SMN1 gene. SMN1 and another type of gene called SMN2 have the instructions for making the SMN protein, and even though SMN2 produces some of the protein, most of it is produced from the SMN1 gene. The issue is, the SMN1 is completely deleted in the SMA gene instructions, so all the baby has left is the small amount of SMN protein produced by the SMN2 (shown in the image above). The SMN protein itself is in charge of taking care of motor neurons, which control muscle movement, causing babies with SMA to be “floppy” and have trouble sitting by themselves. These neurons are located in the brain stem and spine, which also make it very difficult for the infant to lift its head ( Spinal Muscular Atrophy ). Both boys and girls have equal chance of getting the gene because the chromosome this mutation is in is an autosomal chromosome, while x and y chromosomes are the ones that decide whether parents get a new daughter or son. Even if children don’t have SMA when they are born, they can still be carriers of the SMA gene, which means they will be able to pass it on to their children ( About Spinal Muscular Atrophy). = = = = media type="youtube" key="QRJ2pxVxUQw" height="315" width="560" =