Diseases in MCBG

Question 1

Transmissible spongiform encephalopathies

Answer 1

Diseases that involve misfolded proteins (amyloidoses) - degenerative brain disorders with brain having spongey appearance

Question 2

Obesity

Answer 2

Excessive fat accumulation in adipose tissue
Impairs health and is a major preventable cause of death
Associated with increased risk of some cancers, cardiovascular disease and type 2 diabetes

Question 3

Malnutrition

Answer 3

Poor or insufficient nutrition in children in developing countries
Children with chronic disease
They elderly
Alcoholics
Anorexia nervosa sufferers
Institutionalised children and adults

Question 4

Marasmus, why and how

Answer 4

Due to insufficient energy and protein intake
Fat stores mobilised to release fatty acids, converted to ketone bodies = energy, loss of body fat
When glycogen stores used up, muscle protein broken down to release AA for gluconeogenesis = loss of muscle protein

Question 5

Marasmus - anatomical changes

Answer 5

Loss of body fat and muscle mass = wasted
Brain severely affected
Hypotension, bradycardia, thinning of heart muscle
Pit hormones affect
GI tract affected
Very underweight body, thin limbs with little muscle or fat, old man appearance

Question 6

Kwashiorkor, why and how

Answer 6

Normal calorie intake but low protein intake
Liver can’t synthesise sufficient lipoproteins as essential AA not in diet
Lipids accumulate in live = fatty liver, causes hepatic dysfunction

Question 7

Kwashiorkor - body appearance

Answer 7

Oedema in legs
Swollen abdomen
Thin muscles but fat present
Moon face with little interest in surroundings
Flaky skin

Question 8

Why is there oedema in Kwashiorkor?

Answer 8

Liver can’t synthesise albumin
Reduced oncotic pressure of plasma = fluid shifts
Body fluid moves into tissues

Question 9

Primary lactase deficiency

Answer 9

Absence of lactase persistence allele - common in NW Europe

Only in adults

Question 10

Secondary lactase deficiency

Answer 10

Injury to small intestine eg. Crohn’s, coeliac, gastroenteritis
Can be reversed if infection sorted
In both adults and infants

Question 11

Congenital lactase deficiency

Answer 11

Baby can’t digest milk

Caused by recessive mutation in lactase gene

Question 12

Symptoms of lactose intolerance

Answer 12

Bloating/cramps
Vomiting, diarrhoea
Rumbling stomach
Flatulence

Question 13

Crohn’s disease

Answer 13

IBS

Question 14

Galactosaemia

Answer 14

Body can’t use galactose
Galactokinase deficiency - rare
Galactose accumulate or transferase deficiency - common, galactose and G-1P build up
Galactose enters other pathways, using up NADPH which is important in maintaining free sulphydryl groups = inappropriate S-S bond formation - depletes sense of eye, liver, kidney and brain function

Question 15

G-6P dehydrogenase deficiency

Answer 15

In RBC NADPH decreases
S-S bonds formed
Proteins aggregate - Heinz bodies, haemolys

Question 16

Aneuploidy

Answer 16

Unusual number of chromosomes

Question 17

Huntington’s disease

Answer 17

Caused by HTT gene = many CAG repeats
Normally 6-39 but in disease there are 35-121, causes neuron degeneration
Mutant protein aggregates in neurones affecting basal ganglia - in cerebral hemisphere in middle of brain
Progressive, late onset disease

Question 18

Ehlers-Danlos syndrome

Answer 18

Mutation in collagen type V or lysine oxidase deficiency causing v stretchy skin

Question 19

Sickle cell anaemia

Answer 19

Anaemia, susceptibility to infection, weak
Autosomal recessive inheritance
Mutation from Glu to Val = sticky hydrophobic pocket allowing polymerisation of HbS into long chains
Sickle cells more likely to lyse and are more rigid

Question 20

Beta thalassaemia

Answer 20

Decreased of absent beta globin chain so alpha chains can’t form stable tetramers = oxygen bound too tightly and can’t be given up

Question 21

Alpha thalassaemia

Answer 21

Decreased or absence alpha globin chain production, B chains form stable tetramer with increased oxygen affinity due to multiple copies of the alpha chain present

Question 22

Haemophilia

Answer 22

Formation of clots sped up due to defect in factor VIII that causes stimulation of serine protease