HomeCoursesMEDSCI 203: Mechanisms of DiseaseLecture 4 Lecture 4 1. Where can new mutations arise?= =(2) In somatic cells or in the germline Where can new mutations arise?= =(2) In somatic cells or in the germline 2. How are most disease associated mutations acquired? Genetically inheritedHow are most disease associated mutations acquired?== Genetically inherited 3. How do new mutations form? (2) "Through endogenous mutations, through mutagens"How do new mutations form? (2)== "Through endogenous mutations, through mutagens" 4. What are mutagens? When environmental factors increase base pair mutation occurrenceWhat are mutagens?== When environmental factors increase base pair mutation occurrence 5. What are the types of mutations? (3) "Chromosome disorders, single gene disorders, complex/multifactorial disorders"What are the types of mutations? (3)== "Chromosome disorders, single gene disorders, complex/multifactorial disorders" 6. What are chromosomal defects caused by? Excess or deficiency of genes in whole chromosomes (many genes)What are chromosomal defects caused by?== Excess or deficiency of genes in whole chromosomes (many genes) 7. What is trisomy 13? Patau syndromeWhat is trisomy 13?== Patau syndrome 8. What is trisomy 21? Down’s syndromeWhat is trisomy 21?== Down’s syndrome 9. What are the features of Patau syndrome? (4) "95% cases results in miscarriage, holoprosencephaly (brain fails to divide), heart defects, mental retardation"What are the features of Patau syndrome? (4)== "95% cases results in miscarriage, holoprosencephaly (brain fails to divide), heart defects, mental retardation" 10. What are the features of 45 XO Turner’s syndrome? (4) "Complete or partial monosomy of X chromosome in females, no menstruation, underdevelopment gonadal structure, facial features"What are the features of 45 XO Turner’s syndrome? (4)== "Complete or partial monosomy of X chromosome in females, no menstruation, underdevelopment gonadal structure, facial features" 11. What is Cri Du Chat or 5p monosomy? Mutation that results in deletion of the end of short arm of chromosome 5What is Cri Du Chat or 5p monosomy? ==Mutation that results in deletion of the end of short arm of chromosome 5 12. What are some features of Cri-du-chat syndrome? (4) "Cat-like cry, microcephaly (small head), retardation, heart defects"What are some features of Cri-du-chat syndrome? (4)== "Cat-like cry, microcephaly (small head), retardation, heart defects" 13. Where might single gene disorders occur? (2) In mitochondrial or nuclear genomesWhere might single gene disorders occur? (2)== In mitochondrial or nuclear genomes 14. What is a substitution gene mutation? Where one base pair is replaced by its counterpart (T-A to G-C)What is a substitution gene mutation?== Where one base pair is replaced by its counterpart (T-A to G-C) 15. What are the most common substitution mutations? Transition substitutions where purines replace purines (A <—> G or C <—> T)What are the most common substitution mutations?== Transition substitutions where purines replace purines (A <—> G or C <—> T) 16. What are transvehrsion substitution mutations?= ="Where purines are replaced by pyrimidines ( A <—> T,C or G <—> C,T)" What are transvehrsion substitution mutations?= ="Where purines are replaced by pyrimidines ( A <—> T,C or G <—> C,T)" 17. What is a silent mutation? Where substitution in nucleotide still results in encoding for same amino acid What is a silent mutation?== Where substitution in nucleotide still results in encoding for same amino acid 18. What is a nonsense mutation? Where an amino acid is substituted with STOP codonWhat is a nonsense mutation?== Where an amino acid is substituted with STOP codon 19. What is a missense mutation? Where an amino acid is substituted with a different amino acid What is a missense mutation?== Where an amino acid is substituted with a different amino acid 20. What are the types of missense mutations? (2) "Conservative (similar amino acid), non-conservative (dissimilar amino acid)"What are the types of missense mutations? (2)== "Conservative (similar amino acid), non-conservative (dissimilar amino acid)" 21. What is a frameshift mutation? Insertion or deletion of a base or bases in DNA which results in entirely different sequencing of amino acids from point of insertion or deletionWhat is a frameshift mutation?== Insertion or deletion of a base or bases in DNA which results in entirely different sequencing of amino acids from point of insertion or deletion 22. What is the effect of a missense mutation depedent on? Whether the replacement amino acid is similar or dissimilar to the originalWhat is the effect of a missense mutation depedent on?== Whether the replacement amino acid is similar or dissimilar to the original 23. What is the effect of a nonsense mutation depedent on? How near the end of the DNA the mutation occursWhat is the effect of a nonsense mutation depedent on?== How near the end of the DNA the mutation occurs 24. What is the effect of the severity of a frameshift mutation depedent on? (3) "Stability of the product, extent of truncation (how near the end of DNA), the functional importance of missing amino acids"What is the effect of the severity of a frameshift mutation depedent on? (3)== "Stability of the product, extent of truncation (how near the end of DNA), the functional importance of missing amino acids" 25. Where in the DNA do the majority of pathogenic mutations occur? Protein coding regionWhere in the DNA do the majority of pathogenic mutations occur?== Protein coding region 26. Where does 10% of pathogenic mutations occur? Intronic (RNA) sequencesWhere does 10% of pathogenic mutations occur?== Intronic (RNA) sequences 27. Where do 1% of pathogenic DNA mutations occur? Promoter/enhancer regions of DNAWhere do 1% of pathogenic DNA mutations occur? ==Promoter/enhancer regions of DNA 28. What is a point mutation? Where one base is replaced by another which doesn’t have a great effect on the rest of the gene (silent or missense mutation)What is a point mutation?== Where one base is replaced by another which doesn’t have a great effect on the rest of the gene (silent or missense mutation) 29. What frameshift mutation may have a less effect on protein function? Where 3 base pairs are inserted or deleted meaning the remaing amino acids will still encode correctly (although frameshift has still occurred)What frameshift mutation may have a less effect on protein function?== Where 3 base pairs are inserted or deleted meaning the remaing amino acids will still encode correctly (although frameshift has still occurred) 30. Which 3 base mutation results in severe phenotypical pathology? ΔF508 - cystic fibrosismutationWhich 3 base mutation results in severe phenotypical pathology?== ΔF508 - cystic fibrosismutation 31. What are characteristics of an autosomal recessive inheritance? (3) "Appears in siblings - not parents, males and females equally affected, 1 in 4 risk to children of proband"What are characteristics of an autosomal recessive inheritance? (3)== "Appears in siblings - not parents, males and females equally affected, 1 in 4 risk to children of proband" 32. How many CF carriers are symptomatic? "1:2,000"How many CF carriers are symptomatic?== "1:2,000" 33. How many carriers of CF are asymptomatic? 1:30How many carriers of CF are asymptomatic?== 1:30 34. What are the main features of CF? (4) "Sinusitis, lung infections and thick mucous buildup, salty sweat, complications with liver, pancreas, intestines and reproductive organs"What are the main features of CF? (4)== "Sinusitis, lung infections and thick mucous buildup, salty sweat, complications with liver, pancreas, intestines and reproductive organs" 35. What are the characteristics of autosomal dominant inheritance? (3)== "Phenotype appears in every generation, each child has 1 in 2 chance of inheriting mutation, males and females equally affected" 36. What are the characteristics of an X-linked recessive inherited mutation? (3)= ="Males affected more than females due to X inactivation in heterozygous females, Affected male will pass X-linked mutation to all daughters not to sons, may be transmitted through a series of female carriers." What are the characteristics of an X-linked recessive inherited mutation? (3)= ="Males affected more than females due to X inactivation in heterozygous females, Affected male will pass X-linked mutation to all daughters not to sons, may be transmitted through a series of female carriers." 37. What are some examples of x-linked recessive mutations? (3) "Androgen insensitivity syndrome, haemophilia, duchenne muscular dystrophy"What are some examples of x-linked recessive mutations? (3)== "Androgen insensitivity syndrome, haemophilia, duchenne muscular dystrophy" 38. What are some examples of autosomal dominanant diseases? (3) "Huntington’s disease, myotonic dystrophy, hypercholesterolemia"What are some examples of autosomal dominanant diseases? (3)== "Huntington’s disease, myotonic dystrophy, hypercholesterolemia" Loading...
