THE MUTATION
Like described in the diagram above the mutation seen in this disease is a point mutation at codon 608 in exon 11. It changes cytosine to thymine. Therefore the splice site is activated in Exon 11. This leads to the synthesis of abnormal Lamin A protein which is known as Progerin.
Why is the LMNA gene so important ?
Where is the Lamina at?
Since there is a mutation…
This means the meshwork of proteins seen in the normal lamina can not be made, and instead a lamina without structure is produced.
Normal Lamina:
Notice: the lamina is in a straight line and all the proteins are organized.
Abnormal Nucleus (Nucleus of a someone with Progeria)
Notice: The lamina is not organized like in the normal nucleus of a cell. The normal meshwork of proteins is not organized because progerin was made and has its farnesyl group still attatched. This is then what causes nuclear blebbling (meaning the cell does not have the normal round shape).
**This abnormality in the nucleus is what scientist believe causes the accelerated aging seen in children with Progeria. **
***It is important to note that this mutation does not happen in all of the cells of someone with Progeria, but only in a percentage of them. In addition, it is also important to note that although children with Progeria age in body at an accelerated pace in mind they accelerate at a normal pace. In mind they are as vibrant and full of energy as any other child their age. This is because the LMNA is not expressed by the brain cells; therefore the gene mutation does not affect the brain.