Lecture 3 Flashcards
symptoms:
classically autossomal recessive
mutation on A to T transversion in the HBB encoding beta-globin.
codon 6: glutamic acid (E) to valine (V). E6V mutation.
mutation results in abnormal hemoglobin (Hbs)
low hemoglobin concentration high reticulocytes hemolytic amemia blood film bony infarctions can cause unequal finger length infections and problem with blood flow
Sickle cell disease
why is sickle cell disease common on some populations much more than others?
people who are carriers for sickle cell disease, dont have the disease, but become protected against malaria.
this is called the heretozygous advantange.
type of mutation on sickle cell disease?
single amino acid mutation. change of a glutamic acid by a valine (hydrophobic)
heterozygous for sickle cell
can have symptoms under oxidative stress
pleiotropy of sickle cell anemia?
a single gene affects multiple seemingly unrelated phenotypic traits.
correlation of pleiotropy with sickle cell?
sickling dont flow well thotugh blood vessels. leadung to phenotype.
also get traped in spleen leading to low blood cell, anemia and megasplenia
what is altered in sickle cell mutation?
restriction site. 5 bp palyndrome
an interrupted palyndrome. separated by a base that is not part of the palyndrome.
how mutation allele of sickle cell is identified?
by PCR and RFLP analysis
how are the mutant and wild type alleles cut with restricted enzymes in sickle cell?
the wild type will be cut with restriction site,
the mutant type will not be cut, because the mutation is in the middle of the restriction site.
gene mutated in hereditary homochromatosis?
HFE gene. C282Y is the most common mutation
what effect does the mutation have on the restriction sites in the HFE locus?
the fragment in the mutation, has another restriction site that gets cut and runs off the gel
turner syndrome karyotype result?
45 X
most cases due to loss of a chromosome after fertilization (mosaicism)
typical characteristic in turner syndrome?
infertile.
how are the gonads in Turner syndrome patients
if 46XY cells are present (mosaicism) tend to develelop malignancies and so it is important to check for their presence
how is PCR used to ID 46 XY cells in turner syndrome?
test the Y chromosomes.
allele specific PCR
similar to ASO hybridization, for small fragments
