More genetics Flashcards Preview

FA Review > More genetics > Flashcards

Flashcards in More genetics Deck (76):
1

What is codominance?

Both alleles contribute to the phenotype

2

What is variable expressivity?

Phenotype varies among individuals with the same genotype

3

What is incomplete penetrance?

Not all individuals with a mutant genotype show the sme phenotype

4

What is pleiotropy?

One gene contributing to multiple phenotypic effects

5

Musty body odor = ?

PKU

6

What is the loss of heterozygosity?

Two hit phenomenon

7

What is a dominant negative mutation?

A heterozygote produces a nonfunctional altered protein that also prevents the normal gene product functioning

8

What is linkage disequilibrium?

Tendency for certain alleles at 2 linked loci to occur together more often that expected by chance

9

What is locus heterogeneity?

Mutations in the same locus produce a similar phenotype

10

What is allelic heterogeneity?

Different mutations in the same locus produce the same phenotype

11

What is heteroplasmy?

Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondrial inherited disease

12

What is uniparental disomy?

here an offspring receives 2 copies of a chromosome from 1 parent, and no copies from the other.

13

What does heterodisomy (a uniparental disomy) result from?

Meiosis I error

14

What does isodisomy (a uniparental disomy) result from?

Meiosis II error

15

What is the Hardy-Weinberg equation?

= {p^2 + 2pq + q^2 : p and q are the frequencies of separate alleles}

16

What are the four assumptions made in the Hardy-Weinberg equation?

1. No mutation
2. Natural selection is NOT occurring
3. Random mating
4. No net migration

17

What is imprinting?

Methylation of a certain set of genes, causing silencing

18

What is the cause of Prader-willi syndrome?

Paternal gene deleted on 15q

19

What is the cause of Angelman syndrome?

Maternal gene deleted on 15q

20

What are the symptoms of Prader-Willi syndrome?

Food seeking, MR, obesity

21

What are the symptoms of Angelman syndrome?

MR, Happy puppet

22

What is the inheritance pattern of hypophosphatemic rickets (vitamin D deficient rickets)?

X linked dominant

23

What is the inheritance pattern of MEELAS and MRRF?

Mitochondrial

24

What is the genetic defect in autosomal dominant polycystic kidney disease? (which two proteins on which two chromosomes)

Mutation in PKD1 on chromosome 16 and PKD2 on 4

25

What is the genetic cause of familial adenomatous polyposis (HNPCC)? Which chromosome is this on?

Mutation of APC gene on chromosome 5

26

What is the genetic defect in familial hypercholesterolemia?

Defective LDL receptor

27

What is hereditary hemorrhagic telangiectasia?

Inherited disorder of blood vessels

28

What is hereditary spherocytosis?

Spheroid erythrocytes due to spectrin or ankyrin defect

29

What is the genetic bases of huntington's disease?

CAG repeats on chromosome 4

30

What are the two neurotransmitters in the brain that are decreased in Huntington's? What two areas of the brain are most affected?

GABA and ACh

Caudate nucleus and putamen

31

What is multiple endocrine neoplasias (MEN)?

Familial tumors of endocrine glands. Associated with the RET gene

32

What is the genetic basis for neurofibromatosis 1?

NF1 gene mutated on chromosome 17

33

What is the genetic basis for neurofibromatosis 2?

NF2 gene mutated on chromosome 22

34

What is tuberous sclerosis?

Neurocutaneous disorder with multi-organ system involvement.

35

What is the von hippel-Lindau disease?

Deletion of VHL gene on chromosome 3

36

Are mucopolysaccharidoses usually AD or AR in inheritance pattern?

AR

37

What is the genetic basis for CF?

Mutation in CFTR gene on chromosome 7

38

What does the CFTR gene code for?

A Na/Cl channel

39

What are the signs of CF? (3)

Salty baby
Contraction alkalosis
Hypokalemia

40

DO CF patients present with hyperkalemia or hypokalemia?

Hypo

41

What is the bacteria that CF patients are often infected with?

Pseudomonas Aeruginosa

42

What is the treatment for CF?

N-acetylcysteine (loosens mucus plugs)

43

What is Bruton's Agammaglobulinemia? What is its mode of inheritance?

X-linked recessive lack of B cells, resulting in no antibody production

44

What is Fabry's disease? What is its mode of inheritance?

X-linked recessive lysosomal storage disease

45

What is Wiskott Aldrich syndrome? What is its mode of inheritance?

X-linked recessive thrombocytopenia

46

What is G6PD deficiency? What is its mode of inheritance?

X-linked recessive lack of glucose-6-phosphate dehydrogenase, resulting in hemolytic anemia d/t loss of glycolysis in RBCs

47

What is Lesch Nyhan syndrome? What is its mode of inheritance?

X-linked recessive loss of HGPRTase used in purine recycling

48

What is the mode of inheritance of Duchenne and Becker muscular dystrophy?

X-linked recessive lack of dystrophin

49

What is Hunter Syndrome? What is its mode of inheritance?

X-linked recessive MPS II from a lack of iduronate sulfatase II

50

What is Ornithine transcarbamylase deficiency? What is its mode of inheritance?

X-linked recessive lack defect in urea cycle (final enzyme in the urea cycle)

51

Early onset muscle weakness that begins at the pelvic girdle and ascends superiorly = ?

Duchenne/becker muscular dystrophy

52

Both Duchenne's and Becker's muscular dystrophy are x-linked recessive inherited disorders. What is the difference between the two?

Duchenne's is frameshift
Becker's is point mutation

53

What is the genetic basis for myotonic type 1 muscular dystrophy? (protein + Gene)

CTG trinucleotide repeat in DMPK gene

54

What is fragile X syndrome?

Trinucleotide repeat in X chromosome, resulting in MR

55

What is the trinucleotide repeat sequence for Huntington's? Friedreich ataxia? Myotonic dystrophy? Fragile X?

Huntington's = CAG
Friedreich ataxia = GAA
Myotonic dystrophy = CTG
Fragile X = CGG

56

Trisomy 13 = ?

Patau

57

Trisomy 18 = ?

Edwards

58

What are the three P's of Patau's?

cleft Palate
holoProsencephaly
Polydactyly

59

What are the symptoms of Edward's syndrome? (3)

MR
Low set ears
Rocker bottom feet

60

What is the Robertsonian translocation?

A non-reciprocal translocation between chromosomes 13, 14, 15, 21, or 22

61

What is Cri0du-chat syndrome?

Congenital microdeletion of short arm of chromosome 5 , causing cat-like cry

62

What is William's syndrome?

Congenital microdeletion of long are of chromosome 7

63

What are the symptoms of 22q11 del syndromes?

Cleft palate
Abnormal Facies
Thymic aplasia
Hypocalcemia
Cardiac defects

64

What causes the hypocalcemia with a deletion of chromeonse 22?

Thymic aplasia

65

What is DiGeorge syndrome?

deletion of chromosome 22, causing thymic aplasia

66

What is velocardiofacial syndrome?

Del of chr 22, causing palate, facial and cardiac defects

67

What are the fat soluble vitamins?

A
D
E
K

68

Vitamin B1 = ?

Thiamine

69

Vitamin B2 = ?

riboflavin

70

Vitamin B3 = ?

Niacin

71

Vitamin B5 = ?

Pantothenic acid

72

Vitamin B6 = ?

Pyridoxine

73

Vitamin B7 = ?

Biotin

74

Vitamin B9 = ?

Folate

75

Vitamin B12 = ?

Cobalamin

76

Which two vitamins are stored in the liver, and are thus not washed out easily?

B12 and B9