Podcast
Questions and Answers
What is the typical recurrence risk for unaffected parents when a new mutation occurs?
What is the typical recurrence risk for unaffected parents when a new mutation occurs?
- High
- Low (correct)
- Very high
- Moderate
In which condition is the risk of new mutations associated with advanced paternal age?
In which condition is the risk of new mutations associated with advanced paternal age?
- Huntington disease
- Sickle cell anemia
- Neurofibromatosis
- Achondroplasia (correct)
Which of the following conditions exemplifies delayed onset of symptoms despite gene inheritance?
Which of the following conditions exemplifies delayed onset of symptoms despite gene inheritance?
- Marfan syndrome
- Ehlers-Danlos syndrome
- Neurofibromatosis
- Huntington disease (correct)
Which of the following best describes 'variable expressivity' in genetic conditions?
Which of the following best describes 'variable expressivity' in genetic conditions?
What does it mean for a phenotype to be caused by variants at different gene loci?
What does it mean for a phenotype to be caused by variants at different gene loci?
Which syndrome is known to have a single locus affecting multiple distinct phenotypes?
Which syndrome is known to have a single locus affecting multiple distinct phenotypes?
How common are new mutations in achondroplasia cases?
How common are new mutations in achondroplasia cases?
Which of the following syndromes is a type of hereditary cancer syndrome?
Which of the following syndromes is a type of hereditary cancer syndrome?
What is a defining characteristic of autosomal dominant inheritance?
What is a defining characteristic of autosomal dominant inheritance?
What is the significance of non-penetrance in genetic inheritance?
What is the significance of non-penetrance in genetic inheritance?
In sex-influenced traits, which of the following statements is accurate?
In sex-influenced traits, which of the following statements is accurate?
What does genetic heterogeneity imply in the context of genetic disorders?
What does genetic heterogeneity imply in the context of genetic disorders?
What does it mean for a trait to be influenced by anticipation?
What does it mean for a trait to be influenced by anticipation?
What is germline mosaicism?
What is germline mosaicism?
Which of the following is true about adult-onset conditions?
Which of the following is true about adult-onset conditions?
How does pleiotropy affect genetic traits?
How does pleiotropy affect genetic traits?
Flashcards
Non-penetrance
Non-penetrance
A genetic variant associated with a specific trait or disease, but the individual doesn't exhibit the associated phenotype or condition.
New mutation
New mutation
A situation where a genetic mutation occurs spontaneously in the germ cells (sperm or egg) of a parent, leading to the offspring inheriting the mutation even though neither parent carries it.
Adult-onset conditions
Adult-onset conditions
A condition where an individual inherits a disease gene but doesn't develop the disorder until later in life.
Anticipation
Anticipation
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Sex-influenced trait
Sex-influenced trait
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Consanguinity
Consanguinity
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Heterogeniety
Heterogeniety
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Pleiotropy
Pleiotropy
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Recurrence Risk for New Mutations
Recurrence Risk for New Mutations
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Late-Onset Disorders
Late-Onset Disorders
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Variable Expressivity
Variable Expressivity
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Genetic Heterogeneity
Genetic Heterogeneity
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Syndromes
Syndromes
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Paternal Age and New Mutations
Paternal Age and New Mutations
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Study Notes
Patterns of Genetic Inheritance-2
- Lecture covers autosomal dominant inheritance and complicating factors like non-penetrance, new mutations, adult-onset conditions, consanguinity, and interaction.
- Sex-limited/sex-influenced traits are also discussed, along with germline mosaicism, anticipation, heterogeneity, and pleiotropy.
- Non-penetrance is when an individual has a disease-causing gene variant but does not show the associated phenotype or condition. This can "skip" generations. Retinoblastoma is an example.
- Autosomal dominant inheritance with sex-limited/sex-influenced traits: Males with one recessive allele will express the trait; females need two recessive alleles to express the same trait. Gene expression can be limited to specific sexes
- New mutation: A change in the egg or sperm that causes the affected individual to be the first in their family to have that condition. Recurrence risk for unaffected parents is low. Achondroplasia is an example of a disorder associated with advanced paternal age.
- Late-onset traits: Diseases that appear in adulthood instead of childhood or at birth. Huntington disease and many hereditary cancer syndromes are examples.
- Variable expressivity: The severity of a genetic disorder can differ among individuals with the same genotype. Neurofibromatosis (NF1, NF2, NF3) and Treacher Collins syndrome are examples.
- Locus heterogeneity: Variants at different gene loci can cause similar or identical phenotypes for a disorder or disease. Ehler Danlos Syndromes, hereditary deafness, retinitis pigmentosa, and tuberous sclerosis are examples.
- Pleiotropy: A single locus can be responsible for a number of diverse and seemingly unrelated phenotypic effects. Marfan syndrome is an example.
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