Finding diseases / Genetic Testing

Question 1

What type of study is the most common type of genetic study?

Answer 1

candidate gene association study

Question 2

What type of study is best for mendelian traits (uncommon alleles with strong effects)?

Answer 2

Genetic linkage

Question 3

What types of study can discover new unknown genes?

Answer 3

Genetic linkage, GWAS

Question 4

What happens to recombination if the loci are too close to eachother?

Answer 4

loci close = tight linkage = lower crossover freq = lower recombination

Question 5

What happens to recombination if the loci are too far from eachother?

Answer 5

loci far= absent linkage = higher crossover freq = higher recombination

Question 6

WAGR

caused by?

Answer 6

deletion in Pax6 locus on 11p13
Wilms tumor
Aniridia
Genital malform
Retardation

Question 7

What type of genetic test should be used for WAGR

Answer 7

chromosomal analysis

Question 8

Chromosomal analysis can diagnose

Answer 8

aneuploidies,

chromosomal: deletions, duplications insertions, rearrangements

Question 9

Chromosomal analysis cannot diagnose

Answer 9

simple gene deletions,
pt mut
nucleotide repeats
small: dup insertions, methylation

Question 10

FISH probes cannot diagnose

Answer 10

• deletions, rearrangements not spec. tested for
• duplications
• pt mut
• small del

Question 11

Microarray can diagnose:

Answer 11

aneuploids
UNBALANCED chromosomal rearrangements
ch del/dup >200kb

Question 12

Microarray cannot diagnose:

Answer 12

del/dup <200kb

balanced ch rearrangements/translocations

Question 13

DNA seq cannot diagnose

Answer 13

larger indels, rearrangements

Question 14

What mode of inheritance is cystic fibrosis?

Answer 14

Autosomal recessive

Question 15

Cystic fibrosis is genetically homogenous/heterogeneous

Answer 15

genetically homogeneous

shows allelic heterogeneity not genetic heterogeneity

Question 16

genetic heterogeneity

Answer 16

multiple genes (when mutated) are associated with same phenotype

Question 17

what mode of inheritance is hypertrophic cardiomyopathy

Answer 17

autosomal dominant

Question 18

hypertrophic cardiomyopathy shows allelic/genetic heterogeneity

Answer 18

both

Question 19

What cofactor would you give for homocystinuria patients

Answer 19

pyridoxine

Question 20

Multiple endocrine neoplasia (MEN)
cause?
mode of inheritance?

Answer 20

RET mutation

autosomal dominant

Question 21

What substance would you avoid for:

G6PD Deficiency

Answer 21

antimalarial drugs
(avoidance)
-you should avoid antimalarial drugs if you are G6PD deficient

Question 22

What substance would you give for:

PKU

Answer 22

low phenylalanine diet

dietary restriction

Question 23

What substance would you give for:

congenital hypothyroidism

Answer 23

thyroxine

replacement

Question 24

What substance would you give for:

urea cycle deficiency

Answer 24

sodium benzoate

diversion

Question 25

What substance would you give for: | hypercholesterolemia

Answer 25

statin drugs (inhibition) Or LDL apheresis (depletion)

Question 26

Fabrys disease | caused by? results in?

Answer 26

deficiency in alpha-galactosidase | resulting in accumulation of glycosphingolipids

Question 27

Fabrys disease | phenotype

Answer 27

``` belly button spots microvascular disease neuropathy nephropathy sweat gland damage ```

Question 28

2 ways to treat Fabrys disease

Answer 28

recombinant enz replacement therapy: alpha-gal or chaperone based therapy

Question 29

Mode of inheritance of Fabrys

Answer 29

x linked

Question 30

Nonsyndromic deafness | caused by?

Answer 30

Mut in GJB2 gene (DFNB1) encoding connexin26

Question 31

What fraction of deafness cases are due to congenital defects? How much of that is due to hereditary/genetic factors?

Answer 31

1/2, 3/4(nonsyndromic)

Question 32

Deafness with retinitis pigmentosa indicates:

Answer 32

usher syndrome

Question 33

Deafness with thyroid goiter indicates:

Answer 33

prendred

Question 34

Deafness with sudden death indicates:

Answer 34

jervell and lange nielson (AR) syndrome

Question 35

Deafness with white forelock indicates:

Answer 35

waardenburg

Question 36

Deafness with 8th n schwannomas indicates:

Answer 36

neurofibromatosis type II

Question 37

Premutation of CGG repeats indicates what?

Answer 37

1. Fragile X associated tremor/ataxia syndrome | 2. Premature ovarian failure

Question 38

TNRs are hyper/hypomethylated

Answer 38

hypermethylated -> reduced/absent FMRP prot

Question 39

Do premutations of CGG have hypermethylation present?

Answer 39

no. Not hypermethylated -> increased FMRP RNA!

Question 40

What substance would you avoid for: | acute intermittent porphyria

Answer 40

barbiturates