Normal and abnormal development

Question 1

Entirely genetic disease

Answer 1

Either inherited or prenatally acquired defects of genes.

Question 2

Multifactorial

Answer 2

Interaction of genetic and environmental factors.

Question 3

Entirely environmental

Answer 3

No genetic component to risk of disease.

Question 4

What are the diseases called that predisposing to tumours?

Answer 4

Pre-neoplastic conditions. (Crohn’s disease to colon cancer)

Question 5

What term describes the lesions from which tumours can develop?

Answer 5

Pre-neoplastic lesions.

Question 6

What is the permissive effect of diseases?

Answer 6

Allowing environmental agents that are non-pathogenic to cause disease. I.e. opportunistic infections.

Question 7

Prenatal factors

Answer 7

• Genetic abnormalities
• Transplacental transmission of environmental agents (Fetal Alcohol Syndrome, maternal rubella infection)
• Nutritional deprivation (critical effects during fetal morphogenesis)

Question 8

What is the Barker hypothesis?

Answer 8

Risk for a disease is programmed partly by nutritional deprivation in utero.

Question 9

Examples of polygenic disorders

Answer 9

Breast CA
AD
DM
OP
Coronary atherosclerosis

Question 9

HLA-B27

Answer 9

Ankylosing spondylitis

Question 9

HLA-DR3, B8

Answer 9

Coeliac Disease

Question 10

Haemophilia

Answer 10

X-linked recessive disorder.

Question 11

Heterozygote advantage

Answer 11

Protection against environmental pathogens (Sickle cell disease in black people - protection against malaria)

Question 12

Genetic abnormalities may be

Answer 12

Inherited

Acquired during conception or embryogenesis

Acquired during postnatal life

Question 13

Inherited or prenatally acquired often lead to..

Answer 13

Congenital metabolic abnormalities or structural defects

Question 14

Neoplasms

Answer 14

Postnatally acquired genetic abnormalities.

Question 15

HOX genes

Answer 15

Homebox genes - highly conserved 183 base pair sequence. Their expression during embryogenesis follows the order in which they are arranged, thereby sequentially directing body axis formation.

Question 16

Mitochondrial DNA

Answer 16

Circular double stranded conformation

High rate of spontaneous mutations

Few introns

Maternal inheritance

Question 17

Genes in mitochondrial DNA encode for…

Answer 17

Enzymes involved in oxidative phosphorylation. Therefore problems are found in genes with high energy demands - muscle cells and neurones.

Question 18

Examples of mitochondrial diseases

Answer 18

Familial mitochondrial encephalopathy and Kearns-Sayre syndrome.

Question 19

Functional genetics

Answer 19

Biochemical abnormality is known - DNA sequence can be probed.

Question 20

Positional genetics

Answer 20

Abnormality is not known - position to a well-known neighbouring gene that is on the same chromosome and will be inherited along.

Question 21

Mutagens have two consequences

Answer 21

Affect embryogenesis: teratogenic

Tumour development: carcinogenic

Question 22

Haptens

Answer 22

Very small molecules are not antigenic (too small on their own) bind to larger molecules i.e. proteins.

Question 23

Diathermy

Answer 23

Thermal injury used in surgery to coagulate and arrest bleeding.