Definitions Flashcards
Give types of inheritance
X-linked Autosomal Recessive Dominant Polygenic Mitochondrial De Novo Imprinting Sex-determined (BRCA)
Define genomic epidemiology
The study of the cause, distribution and control of genetic disease in populations
Define X-linked inheritance
When a gene is passed on via the X-chromosome.
Eg red-green colour blindness, haemophilia A.
Describe autosomal inheritence
When a gene is passed down to offspring via a non-sex chromosome. Eg CF, Sickle cell anaemia.
Describe recessive inheritance
When possession of a single functional gene is sufficient for normal function and does not result in a disease state. Possession of two recessive alleles results in a disease phenotype. Eg Sickle cell, PKU
Describe dominant inheritance
When possession of a single gene variant results in a disease state. Eg Huntington Disease, DMD
Describe polygenic inheritance
Diseases which are a result of several inherited genes and may also have an environmental contribution.
Describe haplo-insufficiency
When one functional/WT copy of a gene is not enough to allow complete function and results in a disease phenotype.
Describe mitochondrial inheritance
Can only be passed from mother to child. When dysfunctional mitochondria lead to a disease state.
Describe De Novo mutations
New mutations, usually at the germline level, that affect offspring but are not present in parents.
Describe sex-determined inheritance
When a disease-causing gene is autosomal but affects one sex more than another due to differences between sexes. Eg BRCA1/2 can cause ovarian cancers - but not in men.
Describe imprinting
A process of epigenetic DNA and histone modifications which can silence genes. Can lead to the expression of a disease-causing gene over a WT gene when neither are mendelian-pattern dominant.
Define prevalence
How many individuals of a population have a disease/trait at a given time
Define incidence
How many new cases of a disease presented within a given time period
