Exam 2 Flashcards
(104 cards)
Affected most persons with the disease or trait are notated as?
Aa
Notation for Affected, rare and sometimes lethal?
AA
Unaffected “normal” persons are notated as?
aa
What is autosomal dominant inheritance?
When a disease or trait is caused by a dominant allele on an autosomal chromosome. Such mutations are expected to result in a phenotypic change
With a mating of Aa x aa what is the ratio of affected to normals?
50:50 or 1:1
broken down as Aa, Aa, aa, aa
With a mating of Aa x aa and the outcome being broken down as Aa, Aa, aa, aa. What are the odds of a 5th child being affected?
Each child is an independent event so the odds are 50:50
What is the most common genetic notation for someone with an autosomal dominant condition?
Heterozygous Aa
What are the 6 key features of someone with an autosomal dominance inheritance pattern?
1- an affected person has an infected parent
2- there is a ‘vertical’ look or pattern of affecteds seen in the pedigree
3-When and affected person mates with a normal, offspring are expected to be affected 50% of the time(and 50% are expected to be normal)
4- when the normal child of an affected person mates with a normal, normal offspring are expected
5- Sometimes an affected person does not have and affected parent, but there is a history of the condition in their family(this is a case of reduced penetrance)
6- Sometimes an affected person will appear in a pedigree with no prior history in that family( even though the condition is known to be dominant) this is a new mutation
What type of genetic disorder is Huntington’s Disease?
Autosomal dominant
Huntington’s disease:
Characterized by?
Mutation?
On set?
- progressive involuntary twitching, personality change and dementia, and death
- mutant gene has undergone a trinucleotide repeat or expansion mutation
- this is a age onset disease that usually sets in at around 40 yrs of age
What type of genetic disorder is Osteogenesis Imperfecta?
Autosomal dominant
Osteogenesis Imperfecta is a disorder of what?
Connective tissue disorder of type 1 collagen
OI is characterized by what?
brittle fragile bone disease and includes short stature, malformed bones, loose joints, blue sclera, opalescent teeth, and hearing deficit
There are many types of OI which one is the most common?
Type 1
Neurofibromatosis Type 1 is aka?
Von Recklinghausen Disease
What genetic mode of inheritance is Neurofibromatosis Type 1?
Autosomal dominant
What is Neurofibromatosis Type 1 characterized by?
Multiple neurofibromas
What is Achondroplasia aka?
Achondroplastic dwarfism
What mode of inheritance is Achondroplasia?
Autosomal dominant
What is Achondroplasia characterized by and what is the rate of new mutations?
1 non-proportional dwarfism
2 new mutations account for roughly 75% of all cases, possibly as high as 90%
What mode of inheritance is Marfan Syndrome?
Autosomal dominant
What is Marfan syndrome characterized by?
Tall persons with dis-proportionally long limbs, arachnodactyly, subluxation of the eye lens, and cardio vascular defects
Which mode of inheritance is Polycystic Kidney disease?
Autosomal dominant
What is Polycystic Kidney disease characterized by and what is the time of onset?
Multiple kidney cysts and ADPKD is later onset(young adulthood)