Tuesday 19 October 2010

Trinucleotide Repeat Disorders


Trinucleotide Repeat Disorders General Facts:
  • Mutation that is an expansion of a repetitive sequence of 3 nucleotides.
  • This sequence is prone to instability - ie a dynamic mutation.
  • The length of the repetitive sequence continues to increase as the cells divide throughout life - 'somatic instability'.
  • Produces predominantly neurological disorders.
  • Associated with genetic anticipation - condition severity increasing with each successive generation.
Polyglutamine (PolyQ) Diseases:
  • DRPLA (Dentatorubropallidoluysian atrophy)
  • HD (Huntington's disease)
  • SBMA (Spinobulbar muscular atrophy or Kennedy disease)
  • SCA1 (Spinocerebellar ataxia Type 1)
  • SCA2 (Spinocerebellar ataxia Type 2)
  • SCA3 (Spinocerebellar ataxia Type 3 or Machado-Joseph disease)
  • SCA6 (Spinocerebellar ataxia Type 6)
  • SCA7 (Spinocerebellar ataxia Type 7)
  • SCA17 (Spinocerebellar ataxia Type 17)
Non-Polyglutamine Diseases:
  • DM (Myotonic dystrophy)
  • FRAXA (Fragile X syndrome)
  • FRAXE (Fragile XE mental retardation)
  • FRDA (Friedreich's ataxia)
  • FXTAS (Fragile X-associated tremor/ataxia syndrome)
  • SCA8 (Spinocerebellar ataxia Type 8)
  • SCA12 (Spinocerebellar ataxia Type 12)

Image: Huntington's Disease MRI (Radiology Picture of the day) (cc)
Tags: Dynamic Mutation - Fragile X Syndrome - Huntington's Disease - Mutation - Myotonic Dystrophy - Spinocerebellar Ataxia - Trinucleotide Repeat Disorder
Posted by Medicalchemy
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Monday 11 October 2010

Medicalchemy Medical Genetics Blog

This Medicalchemy (TM) blog will be about Medical Genetics related topics.