Genetics

Question 1

Which syndrome is associated with increased risk of Alzheimer’s and why

Answer 1

Down’s syndrome

Due to amyloid precursor protein on C’some 21

Question 2

Angelman’s syndrome - what genetic abnormality and what are its characteristics

Answer 2

Chromosome 15 deletion of maternal origin.

Characterized by severe developmental delay/intellectual disability, severe speech impairment, gait ataxia, tremulousness of the limbs, inappropriate happy demeanor that includes frequent laughing, smiling, excitability

Question 3

Prader-Willi syndrome - what genetic abnormality and what are its characteristics

Answer 3

Chromosome 15 deletion of paternal origin

Severe infantile hypotonia with poor suck and failure to thrive, hypnotism causing genital hyperplasia and pubertal insufficiency, characteristic facial features, early onset childhood obesity and hyperphagia, developmental delay, short stature

Question 4

What genetic disorder has a high association with a schizophrenia like psychosis

Answer 4

Velo-cardio facial syndrome/DiGeorge sequence

22q11 deletion syndrome, conotruncal anomalies, face syndrome and CATCH 22.

Question 5

CGG Trinucleotide Repeat is seen in

Answer 5

Fragile X syndrome

Commonest cause of intellectual disability in males, most common single gene cause of autism

Elongated face, prominent ears, post-pubertal macroorchidism. Mild to severe cognitive impairment in males, less severe in females

Question 6

Which disorder is associated with mental retardation and social anxiety

Answer 6

Fragile X

Question 7

Rett’s syndrome

Answer 7

Mutation in MECP2

• microcephaly, developmental delay

Question 8

Which condition is GAD1 abnormality implicated in

Answer 8

Schizophrenia

Candidate genes are 22q11 - interstitial deletion at this location causes velocardiofacial syndrome/diGeorge syndrome

Question 9

Which disorder are these gene polymorphisms implicated in: DAOA (G72) and BDNF

Answer 9

Bipolar disorder

Question 10

The two main genes associated with which disorder are EN2 and SLC6A4

Answer 10

Autism

Question 11

High MAO-A activity protects against the development of this condition

Answer 11

Antisocial behaviour

Question 12

Chromosome 17 linkage is associated with this condition

Answer 12

Frontotemporal dementia - C’some 17 linked with the FTD-parkinsonism variant

Question 13

Which term describes a single genetic defect producing a variety of defects

Answer 13

Pleiotropy

Question 14

The exchange of genetic material between two chromosomes

Answer 14

Epistasis

Question 15

Any marker that is heritable and found in high rates in families with a disease

Answer 15

Endophenotype

Question 16

Phenotypic variation that can be attributable to genetic factors

Answer 16

Heritability

Question 17

Which lipoprotein is associated with Alzheimer’s disease, specifically earlier onset of it

Answer 17

APOE4

Question 18

Where is the site of the COMT gene linked to dopamine in the frontal cortex?

Answer 18

22q11.2 - it is a deletion syndrome associated with a markedly elevated risk of SCZ in adulthood

A VAL-VAL polymorphism reduces the availability of pre-frontal dopamine

Question 19

What signs are associated with Fragile X syndrome

Answer 19

Hand flapping, gaze avoidance and social anxiety

Question 20

Which chromosome is DISC1 (implicated in schizophrenia) located on

Answer 20

Chromosome 1

Question 21

What is the genetic disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT) and its features

Answer 21

Lesch-Nyan syndrome

Self-mutilating behaviours, hyperuricemia, neurological dysfunction

Question 22

What is the syndrome characterized by a distinctive elfin facial appearance, cheerful demeanor, low nasal bridge and mild to moderate mental retardation with relative strengths in verbal skills and extreme weakness in visuospatial tasks. They tend to hyperfocus on faces and are over friendly with strangers.

Answer 22

Williams Syndrome
- deletion from q11.23 on chromosome 7

Question 23

Which chromosome are PSEN-1 and PSEN-2 genes located on

Answer 23

14 and 1

Question 24

Which chromosome is APP gene located on

Answer 24

21

Question 25

Which chromosome are the APOE genes located on

Answer 25

19

Question 26

Trisomy 18 is also known as

Answer 26

Edward’s syndrome

Question 27

Trisomy 13 is also known as

Answer 27

Patau’s syndrome

Question 28

What is the name of the syndrome cause by a mutation in 17p11 with pronounced injurious behaviour, self hugging and a hoarse voice

Answer 28

Smith-Magenis syndrome

Question 29

Which trinucleotide repeat does Fragile X syndrome involve

Answer 29

CGG in FMR1 gene

Question 30

Which disorder is caused by mutation in genes such as NIPBL and is characterized by microcephaly, arched eyebrows, long eyelashes, growth retardation and ID

Answer 30

Cornelia De Lange syndrome

Question 31

Which genetic syndrome is commonly associated with hyperacusis

Answer 31

Williams syndrome

Question 32

Which chromosomal area is affected in Cri Du Chat

Answer 32

5p

Question 33

What is the most common genetic cause of both FTD and ALS

Answer 33

C9orf72 hexanucleotide repeat expansion

Question 34

What repeat sequence is involved in Fragile X syndrome

Answer 34

CGG

Question 35

What repeat sequence is involved in Friedreich’s ataxia

Answer 35

GAA

Question 36

Which gene is believed to predispose people to developing frontotemporal dementia

Answer 36

Progranulin

Question 37

What genotype is associated with a good response to SSRIs

Answer 37

5HTT gene ‘L’ genotype

Question 38

What disorder are variants at risk locus ADCY2 linked to

Answer 38

Bipolar disorder

Question 39

Monozygotic twins, one of which has bipolar disorder. what is the risk of the other twin developing it

Answer 39

60%

Question 40

How is Androgen Insensitivity Syndrome transmitted

Answer 40

X-linked recessive transmission

Question 41

What’s the chance of someone developing schizophrenia if their identical twin (monozygotic) has it

Answer 41

50%