Down Syndrome and Haemopilia Flashcards
(14 cards)
What causes a non disjunction and what is the results?
Creates 3 copies of chromosomes, extra 1 copy of a chromosome
Down syndrome extra copy on chromosome 21
What is the cause of Down syndrome?
Fertilised embryo receives an extra copy of chromosome 21 sue to error in meiosis - non disjunction
What are some symptoms of Down syndrome?
Some level of learning difficulty, varying in a range of abilities
Hearing loss and heart problems
What are some examples of screening for Down syndrome?
Blood test screen - 11 - 14 weeks
Chorionic villus sample or amniocentesis used to confirm and diagnosis
Why can’t men be a carrier for haemophilia?
The Y chromosome does not have the gene that causes haemophilia
What problems do people have if they have haemophilia?
Unable to control bleeding
Cannot form blood clots
What is haemophilia?
Sex linked genetic disorder located on the X chromosome
What is a treatment option for haemophilia?
Replacing the missing clotting factors
When do females get haemophilia?
When the gene is present on both X chromosomes
Why are men more likely to get haemophilia?
They only have one copy of the allele so cannot be a carrier
They only need one fault allele to have the disorder
What is XH?
Normal
What is Xh?
Haemophilia allele
What is Y?
Males
Why can a father not pass haemophilia onto their son?
As the X chromosome comes from the mother and as the gene is on the X chromosome if the father has it they pass the Y chromosome so that will have no affect on the son
