Tay Sachs: A rare disease- causes progressive damage to the CNS: normally genetically inherited
Bronchopneumonia: Acute inflammation of the lungs and bronchioles
Autosomal Recessive: A characteristic/condition taht only appears in individuals who have both copies of an altered gene; one from each parent
Obstetrician:
Chorionic Villus Sampling: A form of prenatal diagnosis to determine chromosomal or genetic disorders in the foetus (10-12 weeks)
Amniocentesis: Used in prenatal diagnosis of chromosomal abnormalities & foetal infections, & also for sex determination (16 -22 weeks)
Prenatal/ Antenatal: 'Occurring before birth'
What are the different patterns for inheritance?
Single Gene Disorders
Autosomal Dominant
Autosomal Recessive
X-linked Recessive
X- linked Dominant
Y- linked
Mitochondrial
Affected males usually born to unaffected parents- mother usually
asymptomatic carrier; Mainly males affected- Sons will be unaffected,
daughters will be carriers; No male to male transmission; Carrier
females have 50% chance of having affected son
Parents of affected individuals are usually asymptomatic carriers;
Affects either sex; After birth of an affected child, each subsequent
child has a 25% chance of being affected; *Consanguinity
CF; Haemochromatosis;
Sickle Cell; Thalassaemia
Usually at least one affected parent; Transmitted by
either sex; A child w/ one affected & one unaffected
parent has a 50% chance of being affected
A genetic disease in which hexosaminidase enzyme of lysosomes is
defective (Cellular Pathology- D.J.Cook)
Prevents the destruction of one type of glycolipid
(GANGLIOSIDES), which then accumulates in the lyssosmes
Epidemiology: Childhood form of disease high in Ashkenazi Jews (Eastern Europe): 1in
25 people being a carrier, compared to 1 in 250 in general population!
S&S's: Swelling of neurones- can lead to seizures; Poor development; Blindness
Onset: 3 to 6 months- death at ~4/5 y/o
Rare autosomal genetic disorder
Treatment: None yet! But experimental work is on going
Lysosomal Storage Disease
Produced by accumulations of substrates (in this case the glycolipid-
Ganglioside) which aren't metabolised because of deficiencies in
lysosomal enzymes. Excess substrate leads to cell, tissue & organ
dysfunction.
Enzymes need to be delivered across the cell membrane & this has
been achieved by modification
Also known as GM2 Gangliosidosis or Hexosaminidase A
Results from mutations in the HEXA gene on human chromosome 15
ONSET
Types of Tay-Sachs
Classic Infantile
Juvenille
Late Onset
Age of Symptoms Appearance
Around 6 months of age
Between 2 & 5, or anytime during childhood
Adolescence/ early adulthood or even later
What types of Genetic Screening will the family have to undergo? And how do they work? (Benefits & Risks)
Chorionic Villus Sampling
What: Procedure carried out to determine chromosome/ single-gene disorders. Sample of cells-
CHORIONIC villi cells will be taken from the placenta
When: Between 11-13th week
Why: An earlier antenatal screening test suggests a possible problem. Had previous preg's w/
these problems (chromosome abnormality). Family hx of condition like CF or muscular dystrophy
How: Transabdominal CVS- needle inserted through abdo. Transcervical CVS tube/ forceps inserted through the cervix
AMNIOCENTESIS
What: a Diagnostic test to detect serious or potentially serious disorder in foetus.
When:15-20 weeks
Why:
How: A needle is used to extract a sample of amniotic fluid. Amniotic fluid contains cells shed from
the foetus that can be examined for a no. of conditions
Molecular Genetic Tests: Look @ single genes/ short lengths of DNA taken from a person's blood/ body fluids to identify large changes in the gene
Chromosomal Genetic Tests: Look @ features of a person's chromosomes (structure, arrangement,
number). Parts of chromosomes may be missing, there may be extra or even be moved to a diff. part
of another chromosome
Karyotyping- a picture of all of a person's chromosomes. Identity's changes in the no. of chromosomes
Fluorescent In Situ Hybridisation (FISH) analysis- looks @ certain parts of the
chromosomes & can detect very small pieces of chromosomes that are
missing/ extra
What are the Guidelines & Ethics surrounding Abortion?
Abortion is legal in the UK up to 24 weeks under the Abortion At 1967
There is no age limit for treatment
Abortions must be carried out in a hospital/ specialist licensed clinic
2 doctors must agree that an abortion would cause less damage to a woman's physical/ mental health than ontinuing the pregnancy
24 weeks +: Necessary to save woman's life; Prevent frave permanent injury to physical/ mental
health of pregnant woman; There's substantial risk that child would be born w/ serious physical/
mental disabilities
Generally should be carried out as early as poss. Usually <12 weeks and ideally <9 weeks
Risks: Haemorrhage (1 in 1,000); Damage to Cervix (10 in 1,000; Damage to womb (4in 1,000)
Protein synthesis & transport and sorting.
Ribosomes protein synthesis translate RNA into
protein. Proteins made by bound ribosomes
cross the rER membrane. Proteins folded &
modified in ER. Sugars added- glycosylation to
protect proteins
Cytoplasm
Lysosomes
Originate @ Golgi. Contain digestive enzymes.
Defence against disease. Autophagy-clean up of cell
organelles. Autolysis after cell death
Mitochondrion
Energy production as ATP- needed for metabolic
functions, apoptosis. Outer/ Inner Membrane, Cristae
(increases s.a. of inner membrane), Matrix. mtDNA
sER
Synthesis- Carbs, Lipids. Storage (calcium).
Detoxification- ER enzymes detoxify absorbs drugs
toxin (liver & kidney). Modify/ detoxify hydrophobic
chemicals e.g pesticides & carcinogens by converting
them to more water-soluble, conjugated products
G.A.
Synthesis & Packaging of secretiongs (hormones/ enzymes). Packaging
of enzymes w/in vesicles for cellular use. Cell membranes. Proteins
tagged for delivery
Peroxisome
Originate @ rER. Metabolism of lipids (fatty
acids). Detoxifying free radicals from normal
metabolic process : hydrogen peroxide, alcohol.
Liver & Kidner
Imaging: Microscopy (Light, Electron).
Labelling Techniques: Immunocytochemistry or Immunohistochemistry