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
Medicalchemy Group: Images - Mnemonics - Anatomy - Cardiology - Dermatology - Drugs - Endocrinology - Gastroenterology - Genetics - Haematology - Immunology - Infection -Metabolic Medicine - Nephrology - Neuroscience - Nutrition - Oncology - Ophthalmology - Pathology - Pharmacology - Physiology - Psychiatry - Respiratory - Toxicology - Vascular.