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16 Cards in this Set
- Front
- Back
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Point Mutation
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replacement of one DNA base by another
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synonymous mutation
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point mutation, same amino acid coded
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missense mutation
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point mutation, different amino acid coded
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nonsense mutation
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normal codon is changed to a stop codon
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frameshift mutation
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insertions or deletions that aren't multiples of 3 into coding region of DNA changes the reading frame of the message
alters everything downstream from insertion or deletion premature termination, altered transcription, splicing, processing or mRNA |
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Trinucleotide Repeat Mutation
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human genome contains frequent tandem trinucleotide repeat sequences
affected sequences share the nucleoside guanine and cytosine |
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Fragile X syndrome
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expansion mutation
250-4000 tandem repeats of the sequence CGG within FMR-1 gene |
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Marfan Syndrome
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Affects connective tissue
Missense mutation of FBN1 prevents production of fibrillin which is essential for the formation of elastic fiber |
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Maran Syndrome Clinical features
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skeletal abnormalities: tall stature, long arm span, arachnodactyly, high arched palate, pectus deformities (excavation, carinatum)
weak tendons, ligaments, joint capules (double-jointed) lens dislocation cardiovascular disorders: mitral valve prolapse, dilation of aortic ring, dissecting aortic aneurysm |
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Ehlers-Danlos Syndromes
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Connective tissue = collagen defect
Hyperelasticity and fragility of the skin joint hypermobility (human pretzels) bleeding diathesis spontaneous rupture of large blood vesssles, bowel and the gravid uterus many varities |
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Osteogenesis Imperfect
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four types all affecting synthesis of type 1 collagen leading to bone fragility
normal appearnace at birth Fractures occur during infancy and when learning to walk Blue Sclera Hearing loss because bones of middle ear restrict mobility |
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Neurofibromatosis Type 1
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NF1 gene produces neurofibromin, which is a tumor suppressor gene
Lof - formation of neurofibromas cutaneous and subcutaneous neurofibromas: involve larger peripheral nerves causing disfigurement of face or extremities pigment skin lesions: numerous light brown skin patches freckling lisch nodules-melanocytes scholiosis, pseudoarthrosis, bone cysts, malignancy, intellectual impairment |
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Neurofiboma
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benign peripheral "nerve" tumors composed of proliferatng Schwann cell and fibroblasts
asymptomatic- may cause radiculopathy or neuropathy increase in size and number w/ age |
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Familial Hypercholesterolemia
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abnormalities in LDL receptor, which normally removes LDL from blood
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Familial Hypercholesterolemia: Heterozygotes
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xanthomas before age 30, Coronary artery disease, mean blood cholesterol level 350 mg/dL
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Familial Hypercholesterolemia: Homozygotes
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blood cholesterol 600-1200 mg/dL
Xanthomas and athersclerosis in childhood |
