Genetics

Question 1

What is multifactorial in terms of genetics?

Answer 1

Environmental influences act on a genetic predisposition- 1 organ system is usually affected.

Question 2

Single gene ?

Answer 2

Dominant or recessive can affect structural proteins, enzymes and receptors (mendelian)

Question 3

Chromosomal means what in terms of genetics?

Answer 3

Thousands of genes multiple organ systems, usually de novo (from beginning)

Question 4

Mitochondrial

Answer 4

mitochondrial dna

Question 5

Where does mitochondrial dna come from?

Answer 5

Mother

Question 6

What is genetic penetrance?

Answer 6

If fully penetrant then environmental factors/other genes have no effect

Question 7

What is characteristic of downs syndrome?

Answer 7

Trisomy of 21st chromosome, protruding tongue, short femurs, sandal gap, simmian line, round face, sunken eyes. 47 XX +21

Question 8

Three types of reasons for downs?

Answer 8

Mosaicism, robertsonian and translocation

Question 9

What is edwards syndrome?

Answer 9

trisomy 18

Question 10

P’tau syndrome?

Answer 10

Trisomy 13

Question 11

Klinefelter syndrome?

Answer 11

47XXY Infertility 1 in 1000

Question 12

Turner syndrome ?

Answer 12

45XO 1 in 5000 females (primary amenorrhoea, short stature)

Question 13

What are microdeletions and lead to what?

Answer 13

A bit of chromosome missing, identified via specific techniques- prader villi and digeorge

Question 14

what does FISH stand for ?

Answer 14

Fluorescenece in situ hybridisation use to identify parts of chromosome which are abnormal or missing

Question 15

Single gene mutation also know as ?

Answer 15

Mendelian

Question 16

3 types of single gene mutation?

Answer 16

Recessive, dominant and Xlinked

Question 17

Huntingdons has a fault gene on which chromosome?

Answer 17

4

Question 18

Huntingdons shows which feature of genetic disorders?

Answer 18

Genetic anticipation

Question 19

What is gowers manouvre?

Answer 19

In duchennes muscular dystrophy (pushing self up by knees)

Question 20

Moasicism is what?

Answer 20

Abnormal seperation of chromosomes into the cells (mitotic disjunction)

Question 21

Robertsonian is what?

Answer 21

Breakage of 2 acrocentric chromosomes = fusion of long and the short arms are lost

Question 22

Philadelphia chromosome is what?

Answer 22

Between chromosome 9 and 22 translocation leads to CML (chronic myelogenous leukaemia)

Question 23

Chromosomal anomaly where there is a de novo error during meiosis

Answer 23

Numerical anomaly