Flashcards
Th2L03 Monogenic disorders
Cards in this deck (45)
- 1What are monogenic disordersDiseases caused by single locus changes
- 2What are the characterstics of an autosomal recessive trait (6)• Rare in pedigree
• Often skips generations
• Hidden in heterozygous carriers
• Affects males and females equally
• Transmitted by either sex
• Frequency of carries can vary - 3What explains why autosomal recessive disorders pervailHeterozygote must confer a selective advantage
- 4What are the characterstics of an autosomal dominant trait (5)• One dominant allele is sufficient for diseases to be carried on to next generation
• 50% chance of developing disorder with just one mutant allele
• Fequent in pedigree
• Persons are affected in each generation
Affects both genders equally and is transmitted by both genders equally - 5What is a lethal alleleAlleles that cause an organism to die only when present in homozygous condition
- 6What is genetic anticipationWhere the condition becomes more severe (or appears earlier) in successive generations
- 7In what commonly studied AD disease is genetic anticipation seenHuntington's disease
- 8What explains genetic anticipationmeitotic instability
- 9What are the characterstics of an X-linked recessive trait (4)• Gene present on the X chromosome exhibit unique patterns of inheritance in comparison with autosomal genes (because males inherit their X from their moth)
• Will occur more frequently in males
• All daughters of affected fathers are carries
Cannot be passed from father to son - 10What is cystic fibrosisgenetic disorder that occurs in people with two copies of a certain recessive allele
- 11What is the main characteristic of cystic fibrosisexcessive secretion of mucus and consequent vulnerability to infection
- 12What gene is implicated in cystic fibrosisCFTR on chromosome 7
- 13What is the CFTR on chromosome 7 gene code forCystic fibrosis transmembrane conductance regulator gene
- 14What is the Cystic fibrosis transmembrane conductance regulator gene responsible for: (3)Helps create sweat, digestive juices and mucus
Pumps Cl- out of cells (chloride channel on the cell membrane) leading to water existing the cell via osmosis
Maintains a free flowing mucus layer outside of the cell (vital in e.g. alveoli) - 15What allele is this: C (on chromosome 7)Normal wild-type allele encodes for functional CFTR
(Dominant) - 16What allele is this: c (on chromosome 7)Mutant allele lacking 508th codon;
(Recessive) - 17How many mutant alleles are implicated in cystic fibrosisOver 500 but CFTRΔ508 is the most common in N. Europe (70-80% of mutant alleles, (1 in 25))
- 18What are the charactertics and result of mutant CFTRΔ508 (4 steps)Does not exit the endoplasmic reticulum
Never ends up in the Golgi complex
Results in loss of Cl- gradients
Mucus becomes thicker, leads to lung infections, blockage of ducts in pancreas and intestine - 19What is the selective advantage of CF heterozygoteremains unknown
- 20How old is the mutant CF geneover 52,000 years
- 21What is the lifespan of an individual with CFca. 50% reach 40th birthday
- 22Where is Sickle cell anaemia most commonparts of Africa and in people of African origins
- 23What are the rates of sickle cell anaemia in malaria-endemic regions1 in 3
- 24What is the advantage of the Sickle cell heterozygote (HbA/HbS)Less likely to die from malaria (reproduction of the parasite is limited in heterozygote as RBCs rupture prematurely)
- 25What is Huntington's diseaseAn autosomal dominant, hereditary disease marked by degeneration of the brain cells and causing chorea and progressive dementia
- 26What mutation is responsible for Huntington's diseasemutations at HD locus, specifically in the terms of pathogeni repeat expansion of the CAG codon
- 27How many CAG repeats at the HD locus is normalapprox. 28
- 28How many CAG repeats at the HD locus is pathogenic36+
- 29What is the result of 36+ CAG repeats at the HD locusaggregation of protein, cytotoxicity, then neuronal cell death
- 30What is the main characteristic of Myotonic dystrophywasting of muscles
- 31What causes myotonic dystrophyautosomal dominant inheritance of OR de novo triplet expansion of CTG repeats
- 32What is achondroplasiaAn autosomal dominant genetic disorder that results in a form of dwarfism
- 33When is achondroplasia dangerousCan be deadly perinatally when homozygous (lethal allele)
- 34What causes achondroplasiamutation in fibroblast growth factor receptor 3 in chromosome 4
- 35What haemophilia Aan inherited bleeding disorder that is mostly just expressed in males and involves defects in factor VIII leading to haemarthrosis and muscle haemorrhages
- 36What is haemarthrosisbleeding into joint spaces
- 37What is Factor VIIIGene for blood clotting on X chromosome
- 38What is the X-linked recessive probability (of an affected female) in Haemophilia AHalf the sons of a carriers will be affected; half the daughters will be carriers
- 39What causes red-green colour blindnessX-linked recessive trait
Results in lack of specialised retinal cells - 40How common in red green colour blindness in males800 per 10K males
- 41What is Duchenne muscular dystrophyA human genetic disease caused by a sex-linked recessive allele characterised by progressive weakening and a loss of muscle tissue
- 42How common is Duchenne muscular dystrophy3 per 10K males
- 43What causes Duchenne muscular dystrophydeletion of DNA segment
- 44What is X-linked ichthyosisAn X-linked recessive condition affecting males
Pt will have large scales that appear brown in colour
This condition spares the palms and soles
- 45How common is X-linked ichthyosis2 out of 10K males
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- User has deleted their subject information Flashcards on Th2L03 Monogenic disorders, created by Deleted user on 26/08/2016.
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- Deleted user · Aug 2016
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- Aug 27, 2016
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- Created by Emma Allde · Aug 22, 2016
- Copied by Emma Allde · Aug 26, 2016
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