Multifactorial Inheritance 🧬 Flashcards
Liability Threshold Model
The liability threshold model explains the pattern of recurrence risk in families, with higher risk in close relatives and decreased risk in more distant relations.
Concordance in Twins
Concordance in twins refers to the similarity in disease occurrence between twins, with higher concordance rates in genetically identical twins (MZ) compared to fraternal twins (DZ).
Association analysis
A method to test the co-occurrence of a specific allele at a marker locus and a trait in a population by comparing allele frequencies in patients and controls.
Neural Tube Defects
Birth defects such as anencephaly and spina bifida that are caused by incomplete development of the neural tube during pregnancy.
Genome-wide association studies (GWAS)
Studies that compare genomes of individuals with a disease to unaffected individuals to identify genetic markers associated with the disorder.
Threshold Model
Describes a population’s genetic and environmental susceptibility threshold for expressing a disease phenotype, influenced by the combination of genes and environment.
Heritability of quantitative traits
The proportion of variability in a trait that is due to genetic factors, often estimated by twin studies.
Heritability
Heritability is the proportion of observed variation in a particular trait that can be attributed to genetic differences among individuals.
Pyloric Stenosis
Pyloric stenosis is a condition where the pylorus (between stomach and intestines) narrows, more common in males, and affects gastric emptying.
Ascertainment bias
A bias that arises in studies due to the way participants are selected or excluded.
Multifactorial Inheritance
Refers to the inheritance of traits controlled by multiple genes and influenced by environmental factors, leading to continuous variation in phenotypes.
Polygenic Inheritance
Occurs when a trait is controlled by many genes, each making a small contribution to the overall phenotype, such as in complex disorders like heart disease or diabetes.
Single Gene Disorders
Result from mutations in a single gene locus and include autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, and mitochondrial inheritance patterns.
Liability Threshold Model
Explains how a complex disorder’s expression depends on a threshold of genetic and environmental contributions, with a normal distribution of liability determining disease onset.
Multifactorial Inheritance
Multifactorial inheritance refers to traits that do not demonstrate a simple Mendelian pattern and are influenced by both genetic and environmental factors.
