Genetics Flashcards
Autosomal dominant (definition)
A gene on one of the autosomes that may be expressed even if only one copy is present
Autosomal dominant (characteristics)
50% chance of parental transmission;
males and females affected;
phenotype is observed in multiple or every generation with each affected person having an affected parent (vertical transmission on pedigree)
Autosomal recessive (definition)
A genetic disorder that appears only in a patient who has received two copies of a gene mutation, one from each parent. Two genetic mutations on the autosomes.
Autosomal recessive (characteristics)
50% chance of the offspring inheriting one gene mutation carrier;
25% chance of inheriting disease/phenotype;
horizontal transmission on the pedigree proband (known as affected individual) may have affected siblings;
none in parents (carriers), offspring, or other relatives; males and females affected equally.
X-Linked dominant (definition)
Genetic mutations located on the X chromosome requires only one copy for phenotype or disease in males or females
X-Linked dominant (characteristics)
Disorders are rare but most disorders are lethal in pregnancy with male fetus;
no male-to-male transmission;
there is no carrier state; affected males transmit to affected daughters only.
X-Linked recessive (definition)
Genetic mutation located on the X chromosome requires both X chromosomes to be affected in females; males with affected gene will have the disorder
X-Linked recessive (characteristics)
Typically males are affected (rare in females) with transmission from the mother (carrier); 50% of females will inherit the gene from their father and are unaffected carriers; no male-to-male transmission
Mitochondrial mtDNA (definition)
Mutations located in the mitochondria inherited by the mother
Mitochondrial mtDNA (characteristics)
All offspring of affected females; none of the offspring of affected males.
