1. Incomplete Penetrance
    No manifestatons of the mutation even though autosomal dominant

    %penetrance x %recurrance risk/ 100
  2. Variable Expression
    shows variable degrees of the phenotype

    Marfans, OI, NFB1
  3. Pleitropy
    affects multiple organ systems
  4. Locus Heterogeneity
    Different locus, same disease

    • OI- chromosome 7 or 17
    • sensineurial hearing impairment
    • Retinosa pigmentaosa
    • Charcot Marie
  5. Allelic Heterogeneity
    Same locus, different disease

    often due to compound heteros receiving 2 mutations

    NFB1, hemochromo, CF
  6. New Mutation
    unaffected parent --> affected offspring (w no history)

    • due to increased paternal age
    • Pedigree shows one random child affected

    OI, Marf,Achondro
  7. Germline Mosaicism
    mutation in germline cells

    differ from new mutation because in NM only 1 child randomly affected, in germline, multiple kids are affected
  8. Triallelic inheritance
    • allele 1: homo
    • allele 2: hetero
    • allele 3: ???

    Bardet Beidle Syndrome
  9. Delayed Age of Onset
    • Huntingtons
    • Hemoch
    • Breast cancer
  10. Triplets
    *show anticipation and age of onset

    Huntingtons (CAG)-paternal-proteincoding-polyglutamate tract exon 1 gain of fnx

    Myotonic (CTG)-maternal- 3' DMPK-global splicing

    Fragile X (CGG)-maternal-promoter 5-FMR1-RISC/miRNA

    Fredrich Ataxia- frataxin-intron-Fe metabolism
  11. Mitochondrial
    • MELAS- tRNA leucine
    • MERFF- tRNA lycine
    • LHON-ND4

    heteroplasmic- depends on how many mutated mitochondria received in each offspring

  12. Digenic
    mutations in 2 genes are aditive and necessary to produce the disorder

    Retinitis Pigmentosa (ROM1+ perpherin)
  13. Imprinting
    • Prader (SNRPN deleted via methylation)-maternal
    • Angelman (UBE3A deleted via methylation)-maternal

    active = unmethylated = cut


    • -parent of origin
    • -uniparental disomy
    • -trisomy rescue
  14. Microdeletions
    • <1.5 MB
    • Prder,Angelman, DeGeorge (venofacial), Williams Syndrome
  15. Manifesting Hetero
    aka Skewed X inactivatioon

    DMD, hemophelia
Card Set
Genetics Midterm