GiM lectures 9,10,11 Flashcards
(45 cards)
What is morphology
scientific study of the structure and form of either animals and plants or words and phrases
What % of births have congenital malformations?
- when are these malformations more likely to be genetic?
2-3%
multiple malformations, dysmorphic, family history
22q11. 2 Deletion
- phenotype
- frequency
- dysmorphology
- also known as?
Very variable phenotype 1/5000 Learning difficulties - 70% Congenital heart defects 75% hypocalcaemia Seizures Immune deficiency Renal malformation Velopharyngeal insufficiency 32% Cleft palate 15% small lip and lower jaw slanted eyes short stature
aka - DiGeorge syndrome
Achondroplasia
- frequency
- mutation type
- risk factors?
- clinical features
1/20,000 autosomal dominant - often denovo - increased with paternal age - rhizomelic limb shortening - short stature - foramen magnum compression - hydrocephalus
Beckwith-Wiedemann syndrome
- frequency
- clinical features
1/10000
Large tongue, ear pits/creases, exomphalos (umbilical herniation of guts), hemihypertrophy, neonatal hypoglycaemia,
microcephaly
increased risk of Wilms tumour
Down syndome
- frequency
- clinical features
1/800
learning difficulties, congenital heart defects, hypotonia in neonates, single palmar crease, cataracts, hearing impairment, hypothyroidism, leukaemia, atlanto-axial instability, alzheimers
What % of the normal population have a single palmar crease?
- unilateral
- bilateral
unilateral = 4% bilateral = 1%
Kabuki syndrome
- frequency
- clinical features
1/30,000
learning difficulities, congenital eart disease 50%, poor growth, hearing impairment, cleft palate, premature breast development, persistent fetal finger pads 96%, flat broad nose, everted eyelids, cleft palate
mosaicism
- how is it diagnosied
- how can it be recognised
diagnosis by skin biopsy
can be hypo/hyper pigmented patches - may follow blaschko’s lines
What are blaschko’s lines
Blaschko lines are thought to represent pathways of epidermal cell migration and proliferation during the development of the fetus. only visible when a condition affecting the skin is present
Peutz-Jeghers Syndrome
- frequency
- clinical features
Treacher collins syndrome
Frequency
inheritance
clinical features
1/50000
autosomal dominant
very variable phenotype
cleft palate, hearing impairment,
Waardenburg syndrome
- frequency
- clinical features
1/250000
sensorineural hearing impairment, irisheterochromia, premature greying, white forelock, areas of skin hypo pigmentation, congenital malformations VSD, hirschprungs
William’s syndrome
- what is it
- frequency
- clinical features
7q11 deletion 1/20,000 learning difficulties cocktail party speech congenital heart disease - supravalvular aortic stenosis, peripheral pulmonary artery stenosis hypercalcaemia, wide mouth, sunken nasal bridge,
What is cocktail party speech
able to speak fluently in small talk but unable to go into deeper complex social issues due to learning difficulties
What is the structure of DNA
deoxyribose ring (5 carbons) -OH on C1,3,5 C1 - binds to nucleotide base C3 - binds to phosphate C5 - binds to phosphate DNA is stable RNA is unstable (transient
What direction is DNA/RNA synthesised
5’ to 3’
What does the shorthand DNA sequence of
5’ AACGT represent
5’ AACGT
TTGCA 5’
Sense strand is the one written and is the one that makes the mRNA
What is the haploid genome size of the following organisms
1) Mycoplasma genitalium
2) E. Coli
3) Schizosaccharomyces pombe
4) Caenorhabditis elegans
5) drosophila melanogaster
6) Human
7) salamander
1) 0.6Mbp
2) 5Mbp
3) 14 Mbp
4) 80Mbp
5) 165Mbp
6) 3000Mbp
7) 50000Mbp
Facts about the Human genome
- how many Mb dsDNA are there per haploid genome?
- What is the size of the largest and smaller chromosome
- what % of DNA is non coding
- How many protien coding genes are there
- 3 000 Mb dsDNA per haploid genome
- Chromosome 1 – 263 Mb
- Chromosome 22 – 39 Mb
- > 90% is non-coding DNA
- Approx. 20 000 protein-coding genes
What are single copy sequences in the human genome
genes
what are repetitive sequences within the human genome
Interspersed repeats - e.g. Alu repeats
Satellite DNA - large blocks or repetitive sequence, heterochomatin
What are Genes?
Functional unit of DNA
Transcription - copied to RNA
Translation - RNA to protein
Components of genes
exons, introns, regulatory sequences (promoters, enhancers, locus control regions)
What parts of protein synthesis occur in the nucleus
What parts of protein synthesis occur in the cytoplasm
Transcription, capping, cleavage and polyadenylation,
(splicing - takes RNA out into cytoplasm)
mRNA - Translation
Protein created
(post translational modificaitions)
