Genetics

Question 1

Both alleles contribute to phenotype of heterozygote

Answer 1

Codominance

Question 2

Phenotype varies among individuals with same genotype

Answer 2

Variable Expressivity

ex. NF1

Question 3

Not all individuals with a mutant genotype show the mutant phenotype

Answer 3

Incomplete Penetrance

BRCA1 gene mutations don’t always cause breast or ovarian cancer

Question 4

One gene contributes to multiple phenotypic effects

Answer 4

Pleiotropy

Question 5

Increased severity or earlier onset of disease in succeeding generations

Answer 5

Anticipation (ex Huntington)

Question 6

Loss of heterozygosity

Answer 6

develops a mutation in a tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops

Question 7

Dominant Negative Mutation

Answer 7

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

Question 8

Linkage Disequilibrium

Answer 8

tendency for certain alleles at 2 linked loci to occur together more often than expected by chance

Question 9

Somatic Mosaicism

Answer 9

mutation propagates through multiple tissues or organs

Question 10

Gonadal Mosaicism

Answer 10

mutation only in egg or sperm cells

Question 11

Arises from mitotic errors AFTER fertilization

Answer 11

mosaicism

Question 12

McCune Albright Syndrome

Answer 12

Cafe-au-lait, early puberty, abnormal bones
if mosaic - survivable
if somatic - lethal

Question 13

Mutations at different loci can produce a similar phenotype

Answer 13

Locus heterogeneity (Albinism)

Question 14

Different mutations in the same locus produce SAME phenotype

Answer 14

Allelic heterogeneity (beta-thalassemia)

Question 15

Heteroplasmy

Answer 15

both normal and mutated mtDNA

variable expression of mitochondrial inherited disease

Question 16

Heterodisomy

Answer 16

meiosis I error

Question 17

isodisomy

Answer 17

meiosis II error or postzygotic chromosomal duplication of one of a pair of chromosomes and loss of the other original pair

Question 18

Hardy-Weinberg

Answer 18

p^2+ 2pq + q^2
2pq is frequency of heterozygosity
p^2 frequency of homozygosity for allele p
X-linked recessive dx in males in q and females is q^2

Question 19

Assumption of Hardy-Weinberg

Answer 19

No mutation occurring at locus, natural selection is not occurring, completely random mating, no net migration

Question 20

Gene from mom is normally silent and Paternal gene is deleted or mutated
Maternal Imprinting

Answer 20

Prader-Willi Syndrome

Question 21

Gene from dad is normally silent and Maternal gene is deleted/mutated
Paternal Imprinting

Answer 21

Angelman Syndrome

Question 22

Hyperphagia, obesity, intellectual disability, hypogonadism, and hyptonia

Answer 22

Prader-Willi Syndrome

Question 23

Happy puppet

Answer 23

Angelman Syndrome, also gets seizures, ataxia and severe intellectual disability

Question 24

transmitted through both parents
mothers transmit to 50% of daughters and sons
Fathers transmit to all daughters but no sons

Answer 24

X-linked dominant

Question 25

Type of inheritance for Hypophosphatemic Rickets

Answer 25

X-linked Dominant

Question 26

Hypophophatemic Rickets

Answer 26

vitamin D resistant rickets, increased phosphate wasting at proximal tubule

Question 27

Ragged Red Fibers

Answer 27

Mitochondrial Myopathies

Question 28

Cysts on both kidneys

Answer 28

Autosomal Dominant Polycystic Kidney Disease

Question 29

PKD1

Answer 29

On chromosome 16, 85% for AD polycystic kidney disease

Question 30

PKD2

Answer 30

On chromosome 4, 15% for AD polycystic kidney disease

Question 31

Familial Adenomatous Polyposis

Answer 31

Autosomal dominant, chromosome 5 (APC gene)

Question 32

Familial Hypercholesterolemia

Answer 32

``` Autosomal dominant, elevated LDL due to defective or absent LDL receptor tendon xanthomas (Achilles Tendon) ```

Question 33

Hereditary Hemorrhagic Telangiectasia

Answer 33

telangiectasia, recurrent epistaxis, skin discolorations, AV malformations, GI bleeding, hematuria Autosomal Dominant

Question 34

Hereditary Spherocytosis

Answer 34

spectrin or ankyrin defect, autosomal dominant hemolytic anemia, increase MCHC osmotic fragility

Question 35

Chromosome Huntington's is on

Answer 35

Chromosome 4

Question 36

cystic medial necrosis of aorta

Answer 36

Marfan Syndrome (autosomal dominant)

Question 37

ret gene

Answer 37

MEN 2A and 2B

Question 38

von Recklinghausen Disease

Answer 38

NF1, chromosome 17 | Autosomal Dominant

Question 39

Bilateral Acoustic Schwannomas and Juvenile Cataracts

Answer 39

Neurofibromatosis 2, Chromosome 22 | Autosomal dominant

Question 40

Cutaneous Neurofibromas

Answer 40

NF1

Question 41

Meningiomas and epndymomas

Answer 41

NF2

Question 42

Numerous benign hamartomas, multisystem involvement

Answer 42

Tuberous Sclerosis, Autosomal Dominant | Incomplete Penetrance

Question 43

von Hippel-Lindau disease

Answer 43

deleted VHL, chromosome 3 | Autosomal Dominant

Question 44

retinal mulberry, rhabdomyoma, sub-ungual fibromas, ashened skin, hematuria

Answer 44

Tuberous Sclerosis | Chr 9 & 16

Question 45

Autosomal Recessive Diseases

Answer 45

Albinism, ARPKD, CF, glycogen storage diseases, hemochromatosis, Kartagener, mucopolysaccharidoses (except hunter syndrome), PKU, sickle cell, aphingolipidoses (except Fabry), thalassemias, Wilson disease

Question 46

Cystic Fibrosis

Answer 46

Chromosome 7, defect in CFTR | commonly Phe508

Question 47

Increased Chloride in Sweat

Answer 47

Cystic Fibrosis

Question 48

Tx for CF

Answer 48

``` N-acetylcysteine to loosen mucus plugs dornase alfa (DNAse) to clear leukocytic debris ```

Question 49

X-linked disorders

Answer 49

Bruton agammaglobulinemia, Wiskott-Aldrich syn, Fabry, G6PD deficiency, Ocular Albinism, Lesch-Nyhan Syn, Duchenne and Beckers, Hunter, Hemophilia A and B, Ornitine Transcarbamylase deficiency

Question 50

Gower Maneuver

Answer 50

Duchenne Muscle dystrophy, frameshift mutation

Question 51

Common cause of death from Duchenne

Answer 51

Dilated Cardiomyopathy

Question 52

Becker Muscular Dystrophy

Answer 52

X-linked point mutation in dystrophin gene

Question 53

CTG trinucleotide repeat expansion in DMPK gene

Answer 53

Myotonic Type 1 Muscular Dystrophy

Question 54

Muscle Wasting, Frontal Balding, Cataracts, Testicular Atrophy, Arrhythmia

Answer 54

Myotonic Type 1 Muscular Dystrophy

Question 55

CGG trinucleotide repeat

Answer 55

Fragile X syndrome

Question 56

methylation and expression of the FMR1 gene

Answer 56

Fragile X syndrome

Question 57

Macroorchidism, mitral valve prolapse, long face with large jaw, large ears

Answer 57

Fragile X syndrome

Question 58

GAA trinucleotide repeat

Answer 58

Friedriech Ataxia

Question 59

CAG trinucleotide repeat

Answer 59

Huntington Disease

Question 60

Brushfield Spots

Answer 60

Whites of the eye in Down's

Question 61

1st trimester: increase nuchal translucency and hypoplastic nasal bone, decreased serum PAPP-A, increase beta-hCG

Answer 61

Down

Question 62

2nd trimester: decreased AFP, increase beta-hCG, decreased estriol, increase inhibin A

Answer 62

Down

Question 63

#1 cause of Down

Answer 63

meiotic nondisjunction of homologous chromosomes

Question 64

Trisomy 18

Answer 64

Edwards Syndrome

Question 65

prominent occiput, rocker-bottom feet, micrognathia, low set ears

Answer 65

Edwards Syndrome

Question 66

Trisomy 13

Answer 66

Patau Syndrome | retarded, rocker-bottom feet, microphthalmia, microcephaly, cleft lip/palate

Question 67

Polydactyly and holoprosencephaly

Answer 67

Patau Syndrome

Question 68

Nonreciprocal Chromosomal Translocation

Answer 68

Robertsonian translocation 13, 14, 15, 21, and 22 occurs on long arms of 2 acrocentric chromosomes

Question 69

microdeletion of short arm Chromosome 5

Answer 69

Cri-du-Chat

Question 70

high pitched crying/mewing, VSD, dumb

Answer 70

Cri-du-Chat

Question 71

Congenital microdeletioin of long arm chromosome 7

Answer 71

deleted elastin gene, Williams Syndrome

Question 72

Elfin facies, dumb, hypercalcemia, well-developed verbal skills, extreme friendliness to strangers

Answer 72

Williams Syndrome

Question 73

Velocardiofacial Syndrome

Answer 73

``` 22q11 deletion (same as DIGeorge) palate, facial, and cardiac defects ```

Question 74

DiGeorge Syndrome

Answer 74

22q11 deletion | thymic, parathyroid, and cardiac defects

Question 75

Who sells the best cookies?

Answer 75

Girl Scouts!