Module 3: Genetic Confounders Flashcards
De novo
- New mutation in individual that was not in previous generation
- Usually either at the egg or sperm level or early in development
Inherited Mutation
-One of the parents has the same mutation
Variable Expression
- A trait where the same genotype may produce phenotypes of varying severity or manifestations
- Often same variation in siblings but worse in children
Penetrance
-The probability of expressing a phenotype, given that an individual has inherited a predisposing gene
Allelic heterogeneity
- A single disorder, trait, or pattern of traits caused by different mutations within a gene
- Ex: Cystic Fibrosis
Locus heterogeneity
- A single disorder, trait, or pattern of traits caused by mutations in genes at different chromosomal loci
- Ex: Deafness, cardiovascular disease, colon cancer
Gonadal Mosaicism
-A condition where
the cells within the individual’s gonads have different genetic makeup (individual cells vary from each other)
Mosaicism
- A condition where the cells within the same person have different genetic makeup (individual cells vary from each other)
- Ex: person w/ skin different colors in different areas
Anticipation
- Earlier age of onset in subsequent generations
- Ex: Myotonic dystrophy, weak muscles that worsen and show earlier in each generation
Sam has Marfan syndrome (AD) and both his parents are normal. What is the chance Sam’s child will have Marfan syndrome?
50%
What term describes when a condition can range from mild to severe in the same family?
Variable expression
What term describes why 80% of individuals with a mutation in gene X will have symptoms and 20% will be asymptomatic?
Penetrance
What phenotype would you expect in an individual with gonadal mosaicism for the neurofibromatosis (MF) gene?
No clinical symptoms of the condition
