Autosomal Dominant Flashcards Preview

M2M Unit II > Autosomal Dominant > Flashcards

Flashcards in Autosomal Dominant Deck (46):
1

Law of Segregation

each parent passes one randomly selected allele for each trait

2

Law of Independent Assortment

separate genes are passed independently of one another

3

Autosomal Dominant traits are manifested in _______.

homozygotes and heterozygotes

4

Autosomal Dominant traits map to an _______.

autosome

5

Autosomal Dominant traits are manifested in which gender?

both males and females

6

Autosomal Dominant traits can be passed on by which parent?

either one

7

Autosomal Dominant pedigrees have ______ patterns.

vertical

8

It is rare to have a _______ autosomal dominant condition.

homozygous

9

Penetrance

having the genotype and showing the phenotype

10

100% penetrance means?

If you have the genotype, you will always show the phenotype

11

Name a disease with 100% penetrace.

achondroplasia

12

What is the incidence rate of achondroplasia?

1:15,000

13

What is the new mutation rate in achondroplasia?

80%

14

What are the signs and symptoms of achondroplasia?

short stature, Rhizomelic limb shortening, trident hands, frontal bossing, small foramen magnum, genu varum

15

Achondroplasia is caused by a ___ mutation in the _____ gene on chromosome ____.

amino acid substitution of G to A; FGFR3; 4

16

Paternal age effect can be seen in diseases such as _____.

achondroplasia

17

What is the paternal age effect due to?

increased error rates in spermatogenesis in older men

18

pure dominant

homozygotes and heterozygotes are equally affected

19

incompletely dominant

homozygotes are more severely affected

20

Which diseases have reduced penetrance?

retinoblastoma, BRCA, Huntington Disease

21

Achondroplasia is fatal in the ______ form.

homozygous

22

What is the incidence rate for retinoblastoma?

1:15,000 live births

23

Retinoblastoma associated protein regulates _____.

the cell cycle

24

Retinoblastoma is ____ penetrant.

90%

25

Retinoblastoma gene is ____ on chromosome ____.

RB1; 13

26

On a pedigree, you might see incomplete penetrance when _____.

a generation is skipped

27

expressivity

the degree to which the phenotype is expressed given a genotype

28

Name 2 diseases with variable expressivity.

1) neurofibromatosis type 1
2) osteogenesis imperfecta type 1

29

Neurofibromatosis type 1 incidence rate? new mutation rate?

1:3000 births; 50%

30

How is neurofibromatosis type 1 clinically diagnosed?

café-au-lait spots, neurofibromas, freckling in axillary or inguinal areas, optic glioma, lisch nodules, osseous lesions, 1st degree relative

31

1st degree relative

share 50% of your genes (parents, siblings, children)

32

What is the mutation in neurofibromatosis type 1? What kind of mutation? What chromosome?

NF1; loss of function; 17

33

What is the incidence rate of osteogenesis imperfect type 1?

1:30,000

34

What are the signs and symptoms of osteogenesis imperfect type 1?

multiple fractures, mild short stature, adult onset hearing loss, blue sclera

35

What is the mutation in osteogenesis imperfect type 1? What does it do? Which chromosome?

COL1A1; reduces collagen production by half; 7

36

What is the incidence rate of Marfan Syndrome? What is the new mutation rate?

1:5000; 50%

37

What is the mutation in Marfan Syndrome? What does it do? Which chromosome?

FBN1; decreases microfibrils and increases flexibility and stretching of tissues; 15

38

locus heterogeneity

a mutation in more than one locus causing the same clinical condition

39

What is an example of a locus heterogeneity disease?

AD polycystic kidney disease

40

What is the incidence rate of AD polycycstic kidney disease? What is the de novo mutation rate?

1:1000; 5%

41

What are the clinical symptoms of AD polycycstic kidney disease?

bilateral renal cycts, cysts elsewhere, vascular abnormalities, renal disease

42

What is the mutation and chromosome in AD polycycstic kidney disease?

1) PKD1 of chromosome 16 (85% of cases)
2) PKD2 of chromosome 4 (15% of cases)

43

What is the incidence rate of familial hypercholesterolemia? What is the new mutation rate?

1:200-500; very low

44

What are the clinical manifestations in familial hypercholesterolemia?

very high cholesterol and LDL; xanthomas; CAD and death

45

xanthomas

cholesterol deposits under the skin

46

What is the mutation in familial hypercholesterolemia?

mutations of genes:
1) LDLK
2) APOB
3) PCSK9