Genetics

Question 1

One gene contributes to multiple phenotypic effects

Answer 1

Pleiotropy

Question 2

Increased severity or earlier onset of disease in succeeding generations

Answer 2

Anticipation

Question 3

If a patient inherits a mutation in a tumor suppressor gene, the complementary allele must be mutated before cancer develops

Answer 3

Loss of heterozygosity

Question 4

Loss of heterozygosity: examples

Answer 4

Retinoblastoma and the two hits hypothesis
Lynch syndrome
Li-Fraumeni syndrome

Question 5

Loss of heterozygosity is not true for

Answer 5

Oncogenes

Question 6

Example of mosaicism

Answer 6

McCune Albright syndrome

Question 7

Mutations at different loci can produce a similar phenotype

Answer 7

Locus heterogeneity

Question 8

Different mutations in the same loci produce the same phenotype

Answer 8

Allelic heterogeneity

Question 9

Exaple of allelic heterogeneity

Answer 9

Beta thalassemia

Question 10

Presence of both normal and mutated mtDNA

Answer 10

Heteroplasmy

Question 11

Offspring receives 2 copies of a chromosome from 1 parent and no copies from the other parent

Answer 11

Uniparental disomy

Question 12

Uniparental disomy that indicates an error in meiosis I

Answer 12

HeterodIsomy

Question 13

Uniparental disomy that indicates an error in meiosis II

Answer 13

IsodIsomy

Question 14

p2+2pq+q2=1

Answer 14

Population at Hardy Weinberg equilibrium

Question 15

Frequency of an X-linked recessive disease in males (Population at Hardy Weinberg equilibrium)

Answer 15

q

Question 16

Frequency of an X-linked recessive disease in females (Population at Hardy Weinberg equilibrium)

Answer 16

q2

Question 17

Hardy Weinberg law assumptions

Answer 17

1. No mutation occurring at the locus
2. Natural selection is not occurring
3. Completely random mating
4. No net migration

Question 18

Examples of mutations in the not imprinted allelle

Answer 18

Prader-Willi
Angelman
Mutation in chromosome 15

Question 19

Paternal gene mutated

Answer 19

Prader Willi syndrome

Question 20

Maternal gene mutated

Answer 20

Angelman

Question 21

Happy puppet

Answer 21

Angelman syndrome

Question 22

Hyperphagia, obesity, intellectual disability, hypogonadism, hypotonia

Answer 22

Prader-Willi syndrome

Question 23

Fathers transmit to all daughters but no sons

Answer 23

X-linked dominant

Question 24

X-linked dominant examples

Answer 24

Hypophosphatemic ricketts
Fragile X syndrome
Alport syndrome

Question 25

Transmitted only through the mother

Answer 25

Mitochondrial inheritance

Question 26

Ragged red fibers

Answer 26

Mitochondrial myopathies: accumulation of diseased mitochondria

Question 27

Hunter syndrome is the only mucopolysaccharidose disease with an ____________ inheritance

Answer 27

Autosomal recessive

Question 28

Cystic fibrosis inheritance and affected gene

Answer 28

Autosomal recessive | CFTR (Cr7): Phe508

Question 29

Most common lethal genetic disease in Caucasian population

Answer 29

Cystic fibrosis

Question 30

Dx of Cystic fibrosis

Answer 30

>60mEq/L Cl in sweat is diagnostic

Question 31

High immunoreactive trypsinogen

Answer 31

Newborn screening that indicates cystic fibrosis

Question 32

Early infancy infection in cystic fibrosis

Answer 32

S aureus

Question 33

Adolescence pulmonary infection in cystic fibrosis

Answer 33

P aeruginosas

Question 34

Suspect if meconium ileus in newborns

Answer 34

Cystic fibrosis

Question 35

Anti-inflammatory agent in cystic fibrosis

Answer 35

Azithromycin

Question 36

Slows down cystic fibrosis progression

Answer 36

Ibuprofen

Question 37

X Linked disorders

Answer 37

``` Oblivious Female Will Often Give Her Boys Her xLinked Disorders: Ornithine transcarbamylase deficiency Fabry disease Wiskott-Aldrich syndrome Ocular albinism G6PD deficiency Hunter syndrome Bruton agammaglobulinemia Hemophilia Lesch Nyhan syndrome Duchenne (and Becker) muscular dystrophy ```

Question 38

Female carriers variably affected depending on the pattern of inactivation of the X chromosome carrying the mutant vs normal gene

Answer 38

X linked recessive disorders

Question 39

Pseudohypertrophy of calf muscles due to fibrofatty replacement of muscle suggests

Answer 39

Duchenne disease

Question 40

Cause of death in duchenne disease

Answer 40

Dilated cardiomyopathy

Question 41

Largest protein-coding human gene

Answer 41

Dystrophine gene (DMD)

Question 42

Results in myonecrosis

Answer 42

Loss of dystrophin in Duchenne disease

Question 43

Non framshift deletions in dystrophin gene

Answer 43

Becker disease

Question 44

Steinert disease

Answer 44

Myotonic dystrophy tipe I

Question 45

Inheritance of Steinert disease

Answer 45

Autosomal Dominant

Question 46

Douchenne and Becker inheritance

Answer 46

XLinked

Question 47

CTG trinucleotide repeat expansion in the DMPK gene

Answer 47

Myotonic dystrophy tipe I: Steinert disease

Question 48

Common findings of Steinert disease

Answer 48

CTG expansion: Cataracts Toupee: early balding in men Gonadal atrophy

Question 49

Patient uses upper extremities to help stand up

Answer 49

Gower sign: muscular dystrophies

Question 50

Trinucleatide repeat in FMR1 gene

Answer 50

Fragile X syndrome

Question 51

Most common cause of inherited intellectual disability and autism

Answer 51

Fragile X syndrome

Question 52

Protruding Chin Macroorchidism Mitral valve prolapse

Answer 52

Fragile X syndrome | CGG repeats: chin, giant gonads

Question 53

Trinucleotide repeat expansion diseases

Answer 53

``` Huntington disease Myotonic dystrophy Fragile X syndrome Friedreich ataxia: Try(trinucleotide) Hunting For my Fragile cageFree Eggs (X) ```

Question 54

Repeats in Huntington disease

Answer 54

CAG: caudate has less ACh and GABA

Question 55

Repeats in myotonic dystrophy

Answer 55

CTG: cataracts, toupee (early balding) and Gonadal atrophy

Question 56

Repeats in Fragile X syndrome

Answer 56

CGG: Chin (protruding), Giant Gonads

Question 57

Repeats in Friedreich ataxia

Answer 57

GAA: Ataxic GAAit

Question 58

Brushfield spots

Answer 58

Down syndrome

Question 59

Most common cause of genetic intellectual disability

Answer 59

Down Syndrome

Question 60

Most common viable chromosomal disorder

Answer 60

Down Syndrome

Question 61

Duodenal atresia and Hirschsprung disease are more common in

Answer 61

Down syndrome

Question 62

Associated with early onset Alzheimer disease

Answer 62

``` Down Syndrome Chromosome 21 (Codes for amiloid precursor protein) ```

Question 63

5% of Down syndrome cases are caused by

Answer 63

Unbalanced Robertsonian translocation (14,21)

Question 64

95% of Down syndrome cases are caused by

Answer 64

Meiotic nondisjunction

Question 65

First trimester US in down syndrome

Answer 65

Increased nucal translucency 3mm Hypoplasic nasal bone Less serum PAPP-A Higher free Beta-hCG

Question 66

Second trimester US in down syndrome

Answer 66

Less alpha-fetoprotein Higher beta-hCG Lower estriol Higher inhibin A

Question 67

Low PAPPA and beta-hCG in first trimester US

Answer 67

``` Edwards syndrome (18 trisomy) Patau syndrome (13 trisomy) ```

Question 68

Findings in Edwards syndrome

Answer 68

``` PRINCE Edwards Prominent occiput Rocker-bottom feet Intellectual disability Nondisjunction Clenched fists Ears low set ```

Question 69

``` Cleft lip/palate Holoprosencephaly Polydactyly Cutis aPlasia Congenital heart disease ```

Answer 69

Patau syndrome

Question 70

Sindrome maullido de gato

Answer 70

Cri-du-chat syndrome: microdeletion of short arm of chromosome 5

Question 71

Microdeletion of long arm of ch 7

Answer 71

Williams syndrome

Question 72

22q11 deletion syndromes

Answer 72

2x1 22q11: aberrant development of 3rd and 4th branchial pouches - DiGeorge syndrome - Velocardiofacial syndrome