Pathologies Flashcards
Genetic disorders causes, genotype and phenotype
Non-disjunction has higher frequency in males or females?
Females
What is the consequence of mutation in the 3’ UTR?
Disturbed translation and localization
What are the genetic causes of Prader-Willi syndrome?
Paternal deletion (70%) - del(15q11-13) Maternal UPD of chromosome 15 (28%) Wrong imprinting (>2%)
A genetic defect can be expressed all over the body of a males while in females it will be expressed in some parts and some part it won’t. This is example of?
Chromosome inactivation
What are the causes for Down syndrome?
Almost always due to meiotic non-disjunction; small chance by Robertsonian translocation (centric fusion), mostly t(14;21)
Robertsonian translocation (centric fusion) can occur in which chromosomes?
13, 14, 15, 21 and 22 (acrocentric chromosomes)
Ring chromosome can occur in which chromosomes
Any chromosome
What are the symptoms of Turner syndrome?
Short stature, webbed neck, sexually undeveloped
What are the chances a kid will inherited an AR disease from his parents, if both are heterozygote healthy (carriers)?
25%
Marfan syndrome- name the inheritance mode, the defected gene and protein
Autosomal dominant, FBN1 gene and fibrillin protein
Fragile X syndrome- name the inheritance mode, the defected gene and the mutation
X-linked dominant, FMR1 gene and it is a triplet repeat disease (more than 200 triplets of CGG)
What are the symptoms of Angelman syndrome?
Developmental retardation
Compulsive movements
Inappropriate laughter (“happy puppet syndrome”)
Poor / incomplete speech ability
Name all the chromosome structural aberrations
Deletion (interstitial or terminal) Duplication Translocation (can be Robertsonian) Insertion Inversion Ring chromosome Isochromosome
Give an example of loss of imprinting (LOI) in a cancer
Loss of IGF2 imprinting in colon cancer (usually, only the maternal is expressed but in colon cancer the paternal is also expressed due to LOI)
What is the consequence of mutation in the polyadenylation site?
Decreased mRNA stability
What is the consequence of anaphase bridge?
Breakage of the chromosome, can be seen as acentric fragment (micronucleus)
How does red-green color blindness is inherited?
X-linked recessive
What is the consequence of exon mutation?
Changed amino acid or truncated protein (i.e., stop codon)
Huntington’s disease manifest earlier and more severely in successive generation. This is example of what?
Anticipation (a special type of variable expressivity)
Which 2 mutations occur in most of the cancers (60%)?
Ras (oncogene) and P53 (tumor suppressor) mutations
Which gene is defected in achondroplasia?
FGF3 gene
What are the chances a kid will inherited an AD disease from his parents, if one is heterozygote (sick) and the other is healthy?
50%
Define in-frame mutation
Triplet nucleotide insertion or deletion that will keep the reading frame
What is the reason for multipolar division?
Atypical duplication and division of the centrosome
What are the genetic causes of Angelman syndrome?
Maternal deletion (70%) - del(15q11-13) Paternal UPD of chromosome 15 (4%) Wrong imprinting (~8%) UBE3A mutation (~8%)
Chimerism can occur due to?
Double fertilization
Dizygotic twins
Gene manipulation
Define frame shift mutation
Insertion or deletion of nucleotide bases that change the reading frame
What is the most common translocation in C-myc incase of Burkitt’s lymphoma? what are the others?
Reciprocal translocations- most common is t(8;14), others are t(2;8) and t(8;22)
What is the consequence of intron mutation?
Errors in splicing or in regulation
What is the inheritance pattern of adult PKD?
AD (remember- ADult is AD)
Replications errors are higher in males or females?
Males
Triplet repeat of CAG is the background of which disease?
Huntington’s disease
Which gene is the most common defected in Waarndenburg syndrome?
Pax3 gene
How many Barr bodies are in a Turner syndrome patient’s cell?
0 (there is no Barr body in Turner syndrome)
What is the consequence of mutation in the 5’ UTR?
Decreased protein synthesis (translation)
What is the mechanism of anaphase bridge?
Merotelic attachment of kinetochore microtubules- one chromatid is pulled from the two poles while the other chromatid is pulled only from one pole
What is the reason fragile X syndrome is more common in males?
Reduced penetrance in females (although it is inherited in X-linked dominant pattern)
Which protein is mutated in androgen insensitivity syndrome (AIS)?
Testosterone receptor
A cystic fibrosis patient has a deletion of F508 in one chromosome and a point mutation in the other allele (of the homologue chromosome). This is example of what phenomenon?
Complex heterozygoty
What will happen if mitosis is not followed by cytokinesis?
Multinuclear (giant) cell will be formed
What is the mutation type in the background of Becker muscular dystrophy?
In-frame mutation (small deletion of trinucleotide repeat)
What are the symptoms of Prader-Willi syndrome?
Obesity
Small hands and feet
Underdeveloped genitalia
Mild mental retardation
What are the most important symptoms of Klinefelter syndrome?
Sexual immaturity (no sperm), breast swelling
What is the inheritance pattern of infantile PKD?
AR
What is the mutation type in the background of Duchenne muscular dystrophy?
Frame-shift mutation (large deletion)
What is the consequence of mutation in the promotor region?
Altered transcription
What are the symptoms of triploidy?
It is lethal (result in death; no symptoms)
What is the result of mutation in sonic hedgehog gene (SHH)?
Cyclopia (rare form of holoprosencephaly), in which the eyes due not separate
