Trigger 10: Genetics and obesity diseases Flashcards
the human genome is made up of how many bases
3000 million
how many types of letters
4
A, T, C,G
variation is caused by the difference in
bases between person to person
Monogenic disease occur when one or two bases (in the same gene)
are mutated and inherited from one or both parents
inherited by one parents
heterozygous
inherited by both parents
homozygous
monogenic diseases are related to mutations in how many genes
1
morbidity and mortality in the 21st century is a results of
genetic and environmental factors
name an environmental factor
driving
name a genetic factor
cystic fibrosis
the majority of mortality and morbidity are
non-communicable diseases such as diabetes, heart disease and cancer which are caused by a mixture of genes and environment
single DNA change cause disease and result in a
mendelian pattern of inheritance
autosomal dominant disease
presence of one mutated allele is sufficing too cause disease (50% chance offspring will have disease too)
indel mutations lead to
frameshifts
framshifts
change the reading frame of codons, meaning codon sequences change
when codon sequences change
so do the amino acids which are coded–> deleterious effect on proteins
missense mutations
point mutations in which a single nucleotide change results in a codon that codes for another amino acid
changes ina mino acids
can change the structure of whole protein
change in amino acids can cause
disease e..g CF
CF is caused by a
sigle gene disorder, meaning inheritance follows a mendelian -recessive inheritance
recessive inheritance
causes disease when both alleles are mutated
who are at increased risk of autosomal recessive diseases
children from consanguineous marriages
- more recessive alleles in the population
what is associated with severe early -onset obesity
large, rare chromosomal deltetions
give an example of a disease caused by large rare chromosomal deletion
Prader-Willi
Prader- willi is a
rare disease- few children have it
Prader- will causes
children to over eat
16p.11.2
16p11. 2 deletion syndrome is a disorder caused by a deletion of a small piece of chromosome 16.
- The deletion occurs a location designated p11.2.
where does the deletion occur on chromosome 16
p11.2
large deletions at 16p.11.2 cause
children to have higher BMIs than their unaffected counterparts
name some rate mutations which cause obesity (4)
1) Leptin
2) LEPR
3) POMC
4) MC4R
LEPR
leptin receptor
mutations in:
1) Leptin
2) LEPR
3) POMC
4) MC4R
cause…
changes in food intake and energy expenditure
mutations in MC4R cause
changes in food intake and energy expenditure
- severe childhood obesity
MC4R stands for
melanocortin 4 receptor
what produces leptin
adipose tissue
during periods of fasting
leptin levels fall
release of leptin during fasting triggers
a set of responses in the brain which restore energy balance e.g. find food source
where does leptin act
on neurones whiten the hypothalamic arcuate nucleus
the hypothalamic arcuate nucleus
is a primary sensor of alteration in energy stores
during fasting a fall in leptin causes
neurones expressing agouti related peptide (AgRP) to increase food intake
at the same time as stimulating AgPR, leptin also
inhibits POMC
POMC neurones
stop you form eating
how do POMC neurones stop you from eating
by reducing the amount of a-MSH (melanocytes stimulating hormone)
a-MSH
melanocytes stimulating hormone
melanocytes stimulating hormone
apetite supressant
POMC and AgRP neurones are
integrated by second order neurones which express melanocortin- 4 receptors
fasting leads to an increase in
food intake which restore energy balance due to a decrease in leptin stimulating AGRP which increases appetites and inhibiting POMC which inhibits apppetite
leptin mutations cause
severe obesity in children
individuals with leptin mutations
live in a perceived state of starvation- so become fat
low leptin inhibits
POMC which usually stops us eating
low leptin stimulates
AGRP which increases appetite
giving children leptin can
enhance weight loss
high leptin stimulates
POMC- causes you to stop eating
high leptin inhibit
AGRP- stop you from eating
Leptin
Leptin suppresses food intake and thereby inducing weight loss.
