Gene Mutations
A purine replaced by purine or pyrimidine replaced by pyrimidine is a
transition base-pair substitution
the most common hereditary disorder in the US (1 in 8 are carriers)
hereditary hemochromatosis (HFE gene Cys282Tyr)
William's Syndrome causes de novo deletion of 25-28 genes on chromosome 7. What 2 critical genes are lost and their functions?
ELN- elastin component
LIMK1- brain expressed kinase, visual-spatial cognition deficits
short telomeric deletion near the end of chrom. 4 results in what syndrome?
Wolf-Hirschhorn (greek warrior helmet NSD2 gene)
what results from nondisjunction during mitotic division?
mosaicism (Turner and Kleinfelter)
polymorphisms are often
Fragile X syndrome (FMR-1 gene, X-linked dom) has this many trinucleotide repeats of CGG
>200 CGG repeats (normal is <40)
one or more complete sets of chromosomes is called?
one or more individual chromosomes is added or removed is called?
polyploidy
aneuploidy
FISH studies can detect which two chromosomal deletion syndromes?
Wolf-Hirschhorn Syndrome & William's Syndrome
nondisjunction in the father effecting the SHOX gene causes what syndrome?
Turner Syndrome (haploinsufficiency)
A missense mutation in the beta globulin chain of hemoglobin is seen in
Sickle Cell Disease (auto recess) (hydrophilic Glu for hydrophobic Val)
>40 CAG repeats on HTT gene on chrom. 4 leads to additional toxic glutamines. This is indicative of complete penetrance of which disease
Huntington's Disease (auto dom)
movement of genetic material between non-sister chromatids on homologous chromosomes
movement of genetic material between nonhomologous chromosomes
crossing over vs translocation
Prader-Willi syndrome can be caused by uniparental disomy or microdeletions in chrom 15. Which parent's homolog was deleted?
Paternal deletion
most inherited metabolic diseases are what classification?
Autosomal recessive
thalassemia alpha and beta produce
homotetramers of globin chain
3 explanations for dominant disorders
haploinsufficiency, GOF mutations, dominant negative mutations
Out of the 6 possible gametes to come from reciprocal translocation, how many are viable?
2
The most common inherited neurological disorder
Type 1A Charcot-Marie-Tooth Disease (PMP22 gene on chrom. 17)
TP53 mutations do not follow the two hit model due to what?
dominant negative effect
BCL11A downregulation increasing HbF levels can be used as a treatment for
beta thalassemia major
Which nucleotide base often fills the space opposite of the apurinic site
Adenine (A)
The most common Robertsonian translocation occurs between which chromosomes?
14q21q
A pericentric inversion...
includes the centromere
What autosomal dominant syndrome has a TP53 mutation that predisposes someone to early-onset cancers?
Li-Fraumeni Syndrome (LFS)