Inheritance of Genetic Disease

likelihood that a clinical condition will occur when a particular genotype is present (complete / reduced)

different pathogenic variants in a single gene associated with multiple different phenotypes

the range of symptoms that can occur in different people with the same genetic condition

one phenotype can be caused by pathogenic variants in multiple different genes

when only some of an individuals cells have a specific variant

error occurs post-zygotically

occur for the first time in an affected individual without a family history

.each inherited trait is defined by a gene pair .parental genes are randomly separated to the sex cells .offspring inherit one allele from each parent cell when sex cells fuse

2 identical changes at a locus - more common in consanguineous families

2 different changes in a gene which are in trans

Dominant usually lethal in males

hemizygous for genes on the X-chromosome

sperm tail not incorporated (falls off), contains all the mitochondria

Randomly - proportion of infected passed on is random

.volume and quantity of sperm decrease with age .copying errors - de novo mutations .selfish sperm hypothesis

.increases chromosome segregation errors during meiosis - aneuploidy embryos produced

cells with certain genetic errors have a selective advantage over other cells - increase in number through clonal expansion