Autosomal Recessive Flashcards
Angelman syndrome involves active _______ from the _______ and inactive __________ from the ________
SNRPN from father
UBE3A from mother
Symptoms of hurler syndrome
Progressive intellectual disability, skeletal abnormalities, short stature, corneal clouding, and course facial features
Diseases with delayed age of onset can reduce
Natural selection against the disease
Example of a heterogenous disease
Osteogenesis imperfecta col1A1 gene on chromosome 17 or chromosome 7
Hereditary hemochromatosis treatment
Bloodletting
The loss of SNRPN can result in:
Prader-Willi syndrome
The hardy-Weinberg equation is used when ____________ is unavailable
Family (individual) history is available
Hurler syndrome is a ______________ disease
Autosomal recessive
P^2 =
Homozygous frequency
Q^2=
Homozygous frequency
It is estimated that each person carries five recessive genes in the heterozygous form that would result in lethal phenotype if they were present in a homozygous state. This is called:
Genetic burden
Treatment of hurler syndrome
Targeted enzyme replacement therapy, hematopoietic stem cell transplant
Penetrance versus variable expression
Penetrance = did inherent, did NOT express
Variable expression = did inherent, did express in some way
Imprinting involves:
Methylation of specific nucleotides in the DNA and generally transcriptionally silences the gene
When an individual consists of more than one distinct population in eggs or sperm is called
Germline mosaicism
What type of disorder is hurler syndrome?
Mucopolysacharidosis, a lysosomal storage disorder
The hardy-weinberg principle states that the frequency of ______ in a population is mathematically related to the frequency of _________ in a population
Alleles
Genotypes
HFE protein function
Detecting the amount of iron in the body and regulates the production of hepcidin, which influences iron absorption and release
A heterogeneous disease is one where mutations:
At different gene loci can produce the same disease phenotype
The hardy-weinberg principle equation is used most commonly for determining the likelihood that an individual is
Carrying a particular recessive disease allele
Reproduction among family members is referred to as:
Consanguinity
How could one with the genotype of retinoblastoma (RB1) not present with the disease?
Reduced penetrance- manifesting a retinoblastoma usually requires a second mutation that inactivated the other RB1 gene allele, 10% of those with the mutant genotype will not develop the disease
Anticipation in inheritance involves:
An earlier age of onset and/or more severe expression in more recent generations of a pedigree due to repeat expansions
Most common cause of death among those with untreated hemochromatosis
Cardiac failure
2pq =
Heterozygous frequency
Example of a disease that can display anticipation
Myotonic dystrophy
Fragile X
Huntington disease
Gene that Hurler syndrome effects
A-L-iduronidase
A= alpha
Hereditary Hemochromatosis specific gene mutation
Single missense mutation
Myotonic dystrophy specific gene mutation
DMPK gene- expansion of a trinucleotide repeat (CTG) in the 3’ untranslated portion of the gene
Hereditary Hemochromatosis is a _______________ disease
Autosomal recessive
The cause of anticipation is believed to be due to
Slippage of DNA polymerase during DNA replication leading to trinucleotide expansion
Germline mosaicism involves a mutation:
Affected all or some of the germ cells in the ovaries or testes, but not enough of their somatic tissue to produce a phenotype in that parents
Hereditary Hemochromatosis effects which gene
HFE (high iron)
A recessive disease can be passed ________ through generations
Silently
Founder Effect:
Intermarriage within small communities can lead to many individuals carrying the same recessive mutations from the founders
UBE3A gene function
Ubiquitin-mediated protein degradation, strongly in the brain (cognition)
Penetrate refers to:
The proportion of individuals carrying a particular genotype that also express the associated phenotype
Prader-Willi syndrome involves active _________ from the ________ and inactive _________ from the _________
UBE3A from the mother
SNRPN from the father
_________ is present more often in pedigrees involving autosomal recessive diseases, especially rare diseased
Consanguinity
Why are males more commonly affected in hereditary hemochromatosis than females?
Delayed onset of disease (~30 years old), delayed further in women due to menstruation blood loss
Hurler syndome results in the
Buildup of glycosaminoglycan in lysosomes
On average, _____ of the offspring of the mating between two heterozygous carriers will be affected with the autosomal recessive disease
1/4
Examples of pleiotropy
Cystic fibrosis, Marfan syndrome, NF1
Loss of UBE3A gene is associated with
Angelman syndrome
A _______ gene is one that exerts its effects on multiple aspects of physiology or anatomy
Pleiotropic
When does re-imprinting occur?
During opogenesis or spermatogenesis
Many recessive diseases involves mutations in genes that encode for
Enzymes
Osteogenesis imperfecta can be a __________ disease
Germline mosaic autosomal dominant
When two or more siblings are affected with an autosomal DOMINANT disease, but both parents are unaffected, ________ should be considered
Germline mosaicism of one of the parents
SNRPN gene function
Small nuclear riboprotein expressed in the brain
