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Genetics
Test 3 Set 4
48
Other
Graduate
02/25/2009

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Term
dystrophin
Definition
in the X-linked dystrophy diseases Duchenne/Becker what is the protein that is deficient
Term
emerin
Definition
in the x-linked dystrophy disease, emery-dreifuss, what is the deficient protein
Term
Fukutin; Merosin
Definition
In Congenital muscular dystrophies (CMD)Fukuyama CMD classic type what are the two proteins that are deficient?
Term
caveolin; sarcoglycans
Definition
In Limb-girdle muscular dystrophies (LGMD) what are the two proteins that are deficient
Term
dysferlin
Definition
in distal dystrophies what is the protein that is deficient
Term
congenital muscular dystrophy
Definition
mutations in 5 glycosyltransferase genes lead to hypoglycosylation of alpha DG and lead to ?
Term
Fukuyama CMD
Definition
a deficiency in Fukutin leads to?
Term
CMD 1C
Definition
a deficiency in fukutin-related protein gene leads to ?
Term
Muscle-brain-eye disease
Definition
a deficiency in POMGnt1 leads to this disease
Term
Walker-Warburg syndrome
Definition
a deficiency in POMT1 leads to this
Term
DMD
Definition
Incidence  1 in 3300 live male births
Lethal in males (reproductive fitness is zero)
 1/3 are predicted to be new mutants and 2/3 have carrier mothers
Term
BMD
Definition
Accounts for 15% of mutations at the locus
Reproductive fitness is high (~70%)
 high proportion are inherited and only about 10% are new mutations
Term
dystrophin
Definition
the following are the major functions of ?? Maintenance of muscle membrane integrity  by linking actin cytoskeleton ot ECM
To position proteins in complex so that they function correctly
May participate in cell-cell and cell-substratum recognition
Term
frameshift
Definition
Almost all deletions causing DMD involve ____ mutations abolishing synthesis of dystrophin
Term
BMD deletions
Definition
are in-frame; hence some protein, although truncated, is synthesized
exemplify allelic heterogeneity
Term
DMD
Definition
what disease does this charcterize; Age of onset: male children at 3-5 years of age (I = 1/3500 )
Slowly progressive muscle weakness, resulting in
awkward gait, inability to run quickly, inability to climb stairs
Pseudohypertrophy of calves  increase in size of the calves as muscles replaced by fat and fibrous connective tissue
Term
Gower's sign
Definition
people with DMD have difficulty rising from the ground and use ?
Term
serum creatine kinase (CK MM)
Definition
what type of serum increase occurs in DMD?
Term
BMD
Definition
Clinical features very similar to DMD, but the disease process runs a much less aggressive course
Mean age of onset 11 years
Many patients remain ambulant until well into adult life
Overall life expectancy slightly reduced
Term
western blot
Definition
using this type of analysis we can conclude that Shorter and reduced amount of dystrophin protein in BMD membrane protein prep.
Complete absence of dystrophin in DMD membrane protein
Term
Multiplex PCR
Definition
Simultaneous amplification of many DNA segments in the same amplification reaction
Term
osteogenesis imperfecta
Definition
Heterogeneous group of disorders characterized by
Bone fragility
Hearing loss
Blue sclera
Abnormality in teeth (dentinogenesis imperfecta)
Due to mutations that alter the structure of type1 collagen  major structural protein of bone and other fibrous tissues
Term
glycine
Definition
fits into the restricted space, where the 3 α-chains come close to each other
Term
2 pro-alpha 1 chains and 1 pro-alpha 2 chain
Definition
what makes up type I collagen
Term
carboxyl
Definition
Mutations in _____ terminal part of the triple helix are more disruptive
Term
null and missense glycine substitution
Definition
what are the two braod classes of mutations in OI
Term
C-terminus, charged, bulkier
Definition
The phenotypic effects of mutations in OI are more severe if
Glycine substitutions are near the ___ ___ of the α-chain
Substituted amino acid residue is ____
Substituted amino acid is much _____than glycine
Term
mild OI
Definition
if only half the normal number of collagen moleules are produced but they are normal results in
Term
3/4
Definition
If half proα1(I) chains are abnormal how much of the collagen is affected?
Term
1/2
Definition
if structurally defective proα2(I) chains are how much of the collagen molecules are affected?
Term
OI type I
Definition
Mild, blue sclerae, brittle bones, but no bony deformity, often presenile deafness; AD; all the collagen is made normal but the quantity is reduced by half and there are infrequent substitutions of glycine. Null alleles that impar the production of pro alpha I chains, such as defects that interfer with mRNA synthesis
Term
OI Type II
Definition
perinatal lethal; severe abnormalties, dark sclerae and death within 1 month, AD. Production of abnormal collagen molecules due to substitution in Gly-X-Y of the triple helical domain, with some bias toward the COOOH-terminal half of the protein. Common missense skeletal mutations in the glycine codons of the genes for the alpha 1 and alpha 2 chains
Term
OI Type III
Definition
progressive forming, fractures often at birth, progressive bony deformity, limited growth, blue sclerae, dentiogenesis imperfecta, hearing loss. Abnormal collagen molecules; gly substitutions of many types in the triple helix. Located throughout the protein. Missense mutations in the glycine condons of the genes for the alpha 1 or alpha 2 chains
Term
OI Type IV
Definition
Normal sclerae, deforming; mild to moderate bony deformity, short stature, fractures, hearing loss, dentinogenesis imperfecta, AD. Abnormal collagen molecules gly substitutions of many types in the triple helix. Located throughout the protein. Missense mutations in the glycine codons of the genes for the alpha 1 or alpha 2 chains
Term
Ehlers-Danlos (EDS) Syndrome
Definition
Clinical features
Hyperextensible skin, easy bruising, “cigarette paper scars”
Hypermobile joints
Ocular fragility
Retinal detachment, corneal rupture
Diaphragmatic hernia
Ruptures in internal organs
Intestine, colon
Term
Type IV EDS
Definition
Mutations in genes for type III collagen that alter synthesis, secretion and structure
Term
EDS VI
Definition
Mutations in lysyl hydroxylase cause this disease
Term
Type VII EDS
Definition
Mutations in type I collagen, affecting cleavage of N-terminal peptides of procollagen by N-peptidases
Term
wild type alleles that are polymorphic
Definition
Characterised by an expansion of repeating units of three or more nucleotides in tandem within the affected gene
Repeat unit often is a three nucleotide sequence, but 4 and 5 nucleotide repeats also may be associated with disease
General features
Genes associated with these diseases all have
Term
anticipation
Definition
Appearance of the disease at an earlier age as it is transmitted through a family
Term
maternally
Definition
Friedrich’s ataxia, myotonic dystrophy, and fragile X syndrome are unstable when ____ transmitted
Term
paternally
Definition
Huntington’s disease repeats expand when transmitted
Term
CCTG
Definition
Myotonic dystrophy 2 (close genocopy of myotonic dystrophy)  repeat of
Term
ATTCT
Definition
Diseases due to pentanucleotide repeat expansion
Spinocerebellar atrophy 10  repeat of
Term
class I
Definition
expansion of noncoding repeats that cause a loss of protein function by impairing transcription of the preRNA from affected gene  fragile X syndrome, Friedrich ataxia
Term
class II
Definition
disorders resulting from expansions of non-coding repeats that confer novel properties on RNA  myotonic dystrophy 1 & 2, fragile X-associated tremor/ataxia
Term
class III
Definition
expansion of codons that confer novel properties on the affected protein  Huntington disease, spinocerebellar ataxias
Term
Fragile X
Definition
Second most common cause of moderate mental retardation
Frequency is 1 in 4000 male births
Name due to a cytogenetic marker on X chromosome at Xq27.3  fragile site where chromatin fails to condense properly during mitosis
X-linked Dominant disorder with reduced penetrance
Caused by expansion of triplet repeat CGG, located in the 5’ untranslated region of the first exon of FMR1 gene
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