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Flashcards in Genetics Deck (12)
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1
Q

what is mendelian disease

A

one that is controlled by a single locus in an inheritance pattern, a mutation in a single gene that is inherited

2
Q

Describe ALS in terms of genetics

A

mutation of SOD1 gene (the gene responsible for controlling excitotoxity)

3
Q

Amyloid Hypothesis of Alzheimer’s

A
  • Amyloid precursor protein
  • gene on chromosome 21
  • mutations alter the process and increase production of beta amyloid
  • only happens for inheritance in early onset Alzheimer’s
4
Q

How can a chromosome structure become abnormal

A
  • duplication
  • inversion
  • deletion
  • insertion
  • translocation
5
Q

Describe chromosome aneuploidy

A
  • occurs in >5% of pregnancies
  • most often trisomy or occasional monosomy
  • can involve all chromosomes but then wouldn’t make it past life
  • autosomal triosomes: 21, 13, 18
  • monosomy X - there are a number of aneuploidies associated with sex chromosomes
6
Q

which human characteristics follow Mendel’s first law

A
  • phenylketonuria
  • huntington’s disease
  • achondroplasia
  • cystic fibrosis
  • sickle cell disease
7
Q

What is an example of a sex-linked recessive disorder

A

Hemophilia B - blood clotting disorder causing easy bruising and bleeding

inherited mutation of gene for factor IX, deficiency of factor IX

8
Q

What causes x-linked red/green colour blindness

A

mother to son passing the mutation on the 23rd chromosome

9
Q

Describe non-mendelian inheritance

A
  • mechanism where inheritance does not follow normal patterns
  • e.g. mitochondrial inheritance (faulty energy production) - may cause muscle disorders (parkinson’s)
10
Q

Describe epigenetics

A
  • inheritance through a change in gene expression without a change in genetic code
11
Q

Genetics - MND

A
  • SOD1 mutation

- C9orf72 mutation (hexonucleotide repeat in gene of unknown function, expansion of 6 bases)

12
Q

Genetics - Huntington’s disease

A
  • mutated HTT gene
  • Tri nucleotide repeat
  • repeat expansions of CAG (codon for glutamine)
  • 0ver 60 repeats in early onset
  • < 27 repeats = unaffected
  • repeat expands through generation (onset gets earlier)