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81 Cards in this Set
- Front
- Back
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what causes immunodeficiency centromeric insatability facial anamolies syndrome
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it is caused by a mutation in the dnmt3b gene and involves the centromeric instability of 1, 9, and 16-this leads to hypomethylation and sticky ends which clump into stars
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what are the symptoms of ICF
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this the facial anomlies syndrome caused by mutation in methylation which leads to facial problems along with mental retardation and prolonged infections
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what form of inheritance is retts syndrome
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X linked dominant=it affects almost exclusively women
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what are the symptoms of retts syndrome
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normal development until 6 to 18 motnhs followed by regression in milesstones and purposeful hand motion loss. also begin to see autistic behavior-this comes from a germline mutation in the mother and is therefore inherited from a phenotypical mother
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what is the causation of retts syndrome
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mutation in the gene encodng MECP2 (which is found on the x chromosome)since methyltion represses genes th elack of the methylation leads to innaprpriate expression in the brain
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what would happen if you dont have the MeCP2 protein
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you will not be able to recruit HDAC1 to a methylated dna strand
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what is the cause of angelmans syndrome
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methylation of chromosome 15 on the mother in position 1. this means that there is a maternal deletion which leads to the happy puppet
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what is the casue of prader willi
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father has a deletion due to methylation on chromosome 15 at position 2
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what is beckwith-wiedemann syndrome
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somatic overgrowth of the internal organs as well as umbilical hernias
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why does BWS occur
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this is beckwith and it occurs due to methylation on chromosome 11 or uniparental disomy
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what is the role of IGF2
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IGF2 is insulin like growth factor and when it is abnormally methylated it lesds to abnormal gene expression and tumors leading to cancer. treat with 5 aza cytidine and sodium butyrate
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what is linkage analysis
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this is when you use certain markers which aere close to certain genes to determine the recombination and the presence of a disease
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what does a 1 on the linkage scale mean
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a 1 means it is random chance and a 0 means that the marker is close to the gene and is always inherited together and rtecombination wont separate them
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when are probes used in genetic testing
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in southerns and northerns-they are typically 20-500bp long
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when are primers used in gentic testing
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in PCR and they are 18-30 bp long
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what is the purpose of ASO's
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18-30bp long which discriminate between mutations. they are detected with radioactive 32 p or with flourescents
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what causes cystic fibrosis
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allele 508 has a 3bp deletion [AGA] ( so in a pcr you run a probe for both normal and deleted and see if they are hetero or homo
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when can you use a allele specific PCR
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when you have a knwn insertion or deletion of DNA
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what is the genetic problem with sickle cell anemia
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you have a polymorphism in a beta globin gene which puts a valine instead of a glu. so it doesnt get cut at the restriction site and so in sickle you have a long piece
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what is the causation of huntingtons
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triple repeat expansion of CAG repeats-if you have more than 40 repeats you will have huntingtons-it is involved with chromosome 4
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what is the inheritance pattern of cystic fibrosis
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recessive
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what is the chemical which can help stimulate cell division in order to take a fish karyotype
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phytohemaglutinin
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what is the chemical which can help stop cell division in meta phase in order to take a fish karyotype
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colchicine or colcemid (you then put the cells in a hypotonic solutioon so they will swell and pop so you can see the chromosomes and put them under a microscope
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what stains the chromosomes for a karyotype g band
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giemsa stain (the giemsa makes the A-T regions dark and the gc regions light
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what is the karyotype of turner syndrome
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45 XO=means that the second sex chromosome (Y) is missing
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what is the karyotype of klinefelter syndrome
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47, XXY-due to non disjunction in a male in the first stage of mieosis
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what is FISH
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flourescent in situ hybridization-you flours a strand of dna after pullin git apart to use it as a probe. it is helpful in microdeletions and trisomy
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what causes di georges syndrome
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microdeletion on chromosome 22- this deletion leads to heart and cns problems
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what is the karyotype of di george syndrome
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22q11
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what is sky or spectral karyotyping
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this is when you use flourescnce to be able to see all the chromosomes at once
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what is the main use of CGH
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to find tumors or chromosomal copy number changes-you can visualize all at once instead of individual probes
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what are microarrays mainly used for
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to compare two differnt samples to identify how genes are differentially expressed
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what is an SNP mutation array
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it is when you see if a probe of a known mutation will hook to see if you have mutations
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what is the casue of beta thalessimia
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fetal hemoglobin is switched to hba hemoglobin which has two alpha and two beta globins. in beta thalessimia you dont have have enough or you have absent beta globins so you dont havre hba and you get a build up of the a globins which leads to problems in the red blood cell and the ROS which leads to rbc destruction and anemia
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what is a corfu deletion
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it is when the beta globin gene has deletions of the cis regulatory elements which leads to beta thalesseimia
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what does a mass spectometer do
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it is used in proteomics to measure the mass to charge ratio of charged particles
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what is a MALDI-TOF
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matrix assisted laser desorption and ionization time of flight=mass spec with very high accuracy-if you know the weight you can analyze peptides, proteins, oligonucs, polypeps etc. you can even tell phosphorylations
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what is ANTICIPATION
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anticipation is when onset of a disorder becomes earlier in subsequent generations
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what is the repeat sequence in huntingtons diesease
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CAG-normal is 9-35....anything above 35 is pathogenic
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what is the repeat sequence in fragile x syndrome
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CGG-normal is 10-50....anything above 200 is pathogenic
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what is the repeat sequence in myotonic dystrophy
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CTG-normal is 5-35....anything above 75 is pathogenic
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what is the inheritance pattern of huntingtons disease
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autosomal dominant
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what is the inheritance pattern of fragile x syndrome
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x linked
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what is the inhertitance pattern of muscular dystrophy
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autosomal dominant
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what happens in huntingtons disease
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degeneration of neurons in the cerebral cortex
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what is the inheritance and anticipation of huntingtons disease
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it is autosomal dominant with paternal anticipation(so only men expand the problem)-it leads to a polyglutamine tract within the huntington protein
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what is meiotic drive
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this is where it is believed that gametes which have repeats have a selective advantage
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in gragile x syndrome whatr is the anticipation pattern and the inheritance pattern
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it is sex linked and shows maternal anticipation-it leads to mental retardation and long face, and enlarged testis
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where do you find the cgg triple repeat in the fragil x syndrome
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you find the repeat in the 5 utr region of the FMR1 gene. the mutation is involved in the RISC complex and the misprocessing leads to mental retardation
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what is the inheritance and anticipation pattern of muscular dystrophy
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it is autosomal dominant with maternal anticipation
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what is the molecular mechanism of muscular dystrophy
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it is a CTG trinucleotide repeat in the 3' region of the DMPK gene(its a protein kinase)-leads to abnormal rna binding
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what are the rules of autosomal dominant
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must be expressed in every generation-
if there is male to male transmission then you can rule out x linked--so all types of male to female transmission patters are seen UNAFFECTED individuals DO NOT produce affected offspring |
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name 8 autosomal dominant disorders
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familial hypercholesterimia
huntingtons (repeat) Myotonic dystrophy (repeat) marfans osteogensis impoerfecta achondroplasia (dwarfism) neurofibromatosis type 1 acute intemittent porphyria |
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retinalblastoma demonstartes what type of inheritance
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autosomal dominant with 90 percent penetrance
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what is pleiotropy
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it is when an autosomal dominant mutation can cause several seemingly unrelated problems--example=tuberous sclerosis
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how does achondroplasia occur
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a new mutation in the gamte stage -so it is spontaneous dominant and not inherited
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what is the reason for achondroplasia
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a mutation in the FGFR3 which codes for a transmembrane receptor which promotes the differentiation of cartilage to bone. so cartilage goes to bone earleir leading to dwarfism
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what is neurofibromatosis NF1
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mutation in the NF1 gene. the neurofibromin is a tumor supressor gene so tumors occur but with VARIABLE EXPRESSIVITY
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what are four main autosomal recessive inherited disorders
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PKU
CYstic fibrosis tay sachs occulo albinism |
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what is cystic fibrosis
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it is autosamla recessive disorder involving a defect in the CF transmembrane conductance regulator (chloride channel)
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what is tay saches disease
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it is an autosomal recessive disease which is due to a deficiency in the hexosaminadase A enzyme. this enzyme is normally found in lsosomes to break down lipids but without the enzyme th elipids accumualte int he brain
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what is phenyketouria
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this is an autosomal recessive disorder whichis due to a deficiency in the enzyme phenylalanine hydroxylase which metabolises phenyalanine into tyrosine
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what is the inheritance pattern of sickle cell anemia and thallessimia
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autosomal recessive
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what is pseudodominat autosomal recessive
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this is when it appears that the pattern is autosomal dominant but it is not because it is actually a homozygous recessive with a heterozygote which produces 50 percent affected offspring
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deafness shows what type of inheritance pattern
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it is controlled by severla different allels but in order to be deaf you must be homozygous recessive for one (just 1 in deafness) to be affected
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what is assortive mating
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when deaf people associate with deaf and so they marry deaf people etc...
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what is a compound heterozygote
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this is when a child inherits a mutation from both the parents who were carrieres of two different traits linked with a disease. so they become infected due to the carrying of both hetorozygous things even though they are not recessive homozygous for either trait
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what type of transmittance is seen in x linked disorders
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no male to male. instead you see a back and forth pattern with male to female called a knights move
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what is the main pedigree thing you look for to rule out x linked recessive transmission
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in x linked recessive there is NO male to male transmission
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whatr type of inheritance is duschene muscular dystrphy
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x linked recessive- this means carrier females give affected sons
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what is the cause of muscular dystrophy
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on the x chromosome you have the DMD gene which codes for dystrophin which links actin to the muscle cell cytoskeleton
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what type of inheritance is hemophilia A
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x linked recessive- caused by disruption of factor 8 gene
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what type of inheritance is seen in glucose 6 phosphat dehydrogenase deficiency
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x linked recessive- conveys malarial resistance and leads to haemolytic crisis
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what is mosaicism
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it is when the female inactivates when x chromosome in each cell
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what is incontinentia pigmenti
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this is female mosaics where you get patches of darker skin where the x has been inactivated
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what is a manifesting heterozygotew
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due to skewed x inactivation in females you have the manifestation of both mutant and normal x chromosome
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name three x linked dominant disorders
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incontineti pigmenti
vitamin d resistant rickets charcot marie tooth disease no male to male transmission |
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what happens pedigree wise in x linked dominant
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an affected male passes the trait to all daughters but no sons
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what gene does x innactivation
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the Xist gene coats one x chromosome and inactivates it
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what is digenic inheritance
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where it takes the addition of two mutant genes to produce the disorder
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how can you tell in a pedigree if a disease is mitochondrial
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there will be no male to male or male to female transmission
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