Core Genetic Diseases

acorrigan's version from 2017-05-10 18:58


Question Answer
What are the core genetic diseases?Duchenne & Becker Muscular Dystrophy, Huntington disease, Cystic Fibrosis
What gene is involved in cystic fibrosis?CFTR a transmembrane cAMP dependent chloride channel
How many mutations are tested for in CF newborn screening? What proportion of CF cases can they detect?Four, these should identify 80% of CF
What is the CF blood spot initially tested for?Blood spot is tested for raised immunoreactive trypsinogen (IRT)
What is the main symptom of CF and what causes it?Viscous mucus along airways and digestive tract due to faulty chloride channel and too much water absorption
What are the main features of Huntington disease?Involuntary jerky movements, known as chorea, cognitive impairment, psyciatric problems
What is the age of onset of Huntington disease?Between 35-50 years
What is the genetic basis of Huntington disease?Trinucleotide repeat expansion (CAG) in exon 1 of the Huntingtin gene HTT
What is the critical number of repeats to cause Huntington's?40 repeats or more show full penetrance
What numbers of repeats show reduced penetrance in Huntington's disease?36-39 repeats have reduced penetrance.
In Huntington's disease, what is anticipation and what number of repeats does this apply to?Anticipation is when the individual themselves is not affected, but the number of repeats is unstable and may expand leaving the following generation at risk of being affected. In HD this happens when there is an intermediate number of repeats (27-35).

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