Wednesday, 21 March 2012

A Cure for Myotonic Dystrophy Type 1?


By: Edwin Sohun (40253567)

Myotonic Dystrophy Type 1 or DM1 is a genetic disease that weakens the muscles. Part of its name comes from the root word myotonia, which is the ability to relax muscles at will. For humans, the severity extends to a point where the muscles no longer perform. Some effects may include muscle contraction or loss of muscle reflexes to return to its original position after it is used. 


As scientifically known, DM1 is cause by the expansion of the CTG nucleotide repeats, also known as the trinucleotide repeat, which occurs in a segment of the Myotonic Dystrophy Protein Kinase (DMPK) gene found on chromosome 19q13.3. Here, the trinucleotide repeat, expands and repeats multiple times in three (3) untranslated regions of the gene. This expansion exceeds the limits of normal repeats, becoming myotonic dystrophy (Genetics Home Reference, 2012). Furthermore, as stated by Turner and Jones (2010), a normal human DNA has a limit of 5 to 37 repeats while a repeat of 50 to 4000 is comparatively high and only found in DM1 patients.

A picture of a normal CTG repeat and an altered CTG repeat
Although DM1 is rare, Foff and Mahadevan (2011) explained that it affects one in every eight thousand (1:8000) caucasian young adults and one in every 20 000 (1:20 000) in Asians and African populations. 

As science advances, we are nearing an age where DM1 will be soon be threatened. Scientists are very close in identifying the causes and the remedies of these genetic mutations. One of the most recent discoveries involving this abnormality is the discovery of some potent molecules that could attack the disease at its root. The research was designed and administered by a group of scientists led by associate professor Matthew Disney from the Scripps Research Institute. This discovery is a series of carefully designed RNA motif-small molecule databases. Since myotonic dystrophy type 1 involves an RNA defect in an individual’s genetic code, the groups’ molecule database targets the RNA to identify lead compounds that could improve defects of the RNA. The groups’ test was based on animal RNA trials, by which when targeted by the lead compounds, showed impressive results by improving protein splicing defects. This test showed that the same could happen in human genes as humans and animals alike are made up of the same cells structure.

In conclusion, advances in science are enabling us to understand causes of diseases at the molecular level.  Myotonic dystrophy type 1 is one that has been leaving scientists, medical specialists and the rest of the world wondering how we can be able to stop it. However, it won’t be long into the future when incurable diseases like DM1 will seem to be curable. Such discoveries by this team is paving the way for more molecular studies and more similar studies will eventually lead to understanding and improving all genetic diseases.


References

Foff  EP & Mahadevan MS 2011, ‘Therapeutics development in myotonic dystrophy type 1’, Muscle & Nerve, Volume 44, Issue 2, pages 160–169, DOI: 10.1002/mus.22090

Genetics Home Reference 2012, Genes, DMPK, Viewed 20 March 2012, http://ghr.nlm.nih.gov/gene/DMPK.

  
Physorg.com 2012, Scientists create potent molecules aimed at treating muscular dystrophy, Viewed 20 March 2012, http://www.physorg.com/news/2012-02-scientists-potent-molecules-aimed-muscular.html.

 

Turner C, & Jones DH 2010, ‘The myotonic dystrophies: diagnosis and management’ J Neurol Neurosurg Psychiatry, Vol 81, Pages 358-367. DOI:10.1136/jnnp.2008.158261



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