Biochem Genetics Diseases with Replication - Comp Exam Study guide.txt

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Biochem Genetics Diseases with Replication - Comp Exam Study guide.txt
2014-11-18 01:11:42
Biochem Genetics Diseases Replication Comp Exam Study guide

Biochem Genetics Diseases with Replication - Comp Exam Study guide
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  1. Telomere shortening and associated diseases
    • shortened telomeres due to exhaustive replicative capacity inflammatory cytokines and growth factors cause activation of nearby cells --> interferes with normal tissue function
    • Result in shortened telomeres
    • responsible for:
    • 1. Dyskeratosis congenita
    • 2. Idiopathic Pulmonary Fibrosis
    • 3. Cancers
  2. Dyskeratosis congenita
    • Inherited X-linked disease, rare disease (1 in 1mil), death at 16 median age
    • Causes of death are bone marrow failure, pulmonary disease and cancer
    • Dyskerin: involved in making ribosomes and pre-mRNA splicing, along with other protein formation. Patients with mutation in dyskerin or other associated proteins may have reduced TERC levels. Mutation in TERT also in DKC
    • These mutations in TERT or TERC genes result in shorter telomere lengths.
  3. Idiopathic Pulmonary Fibrosis
    • fatal lung disease
    • Diagnosis age 50, lifespan of 2-4 years after diagnosis
    • TERT and TERC mutations (ie, nucleotide deletions to make frameshifts and truncated proteins) associated w/IPF
    • these mutations cause shorter telomere lengths of circulating WHITE BLOOD CELLS
  4. Cancer
    • each round of cell division results in DECREASED telomeres
    • stem cells proliferate and telomerase shortening occurs, but the premature exhaustion of these stem cells leads to pulmonary fibrosis or other diseases (DKC), bone marrow failure
    • Mutations in Cell cycle checkbone genes (ie p53) growth of cells continues and telomeres continue to shorten until they cannot protect chromosome ends.
    • This can lead to cancer
  5. Telomerase inhibition
    • results in loss of telomeric DNA and apoptosis
    • telomere dysfunction 1st promotes chromosomal instability that drives early carcinogenesis