Genetics Flashcards
(23 cards)
What is multifactorial in terms of genetics?
Environmental influences act on a genetic predisposition- 1 organ system is usually affected.
Single gene ?
Dominant or recessive can affect structural proteins, enzymes and receptors (mendelian)
Chromosomal means what in terms of genetics?
Thousands of genes multiple organ systems, usually de novo (from beginning)
Mitochondrial
mitochondrial dna
Where does mitochondrial dna come from?
Mother
What is genetic penetrance?
If fully penetrant then environmental factors/other genes have no effect
What is characteristic of downs syndrome?
Trisomy of 21st chromosome, protruding tongue, short femurs, sandal gap, simmian line, round face, sunken eyes. 47 XX +21
Three types of reasons for downs?
Mosaicism, robertsonian and translocation
What is edwards syndrome?
trisomy 18
P’tau syndrome?
Trisomy 13
Klinefelter syndrome?
47XXY Infertility 1 in 1000
Turner syndrome ?
45XO 1 in 5000 females (primary amenorrhoea, short stature)
What are microdeletions and lead to what?
A bit of chromosome missing, identified via specific techniques- prader villi and digeorge
what does FISH stand for ?
Fluorescenece in situ hybridisation use to identify parts of chromosome which are abnormal or missing
Single gene mutation also know as ?
Mendelian
3 types of single gene mutation?
Recessive, dominant and Xlinked
Huntingdons has a fault gene on which chromosome?
4
Huntingdons shows which feature of genetic disorders?
Genetic anticipation
What is gowers manouvre?
In duchennes muscular dystrophy (pushing self up by knees)
Moasicism is what?
Abnormal seperation of chromosomes into the cells (mitotic disjunction)
Robertsonian is what?
Breakage of 2 acrocentric chromosomes = fusion of long and the short arms are lost
Philadelphia chromosome is what?
Between chromosome 9 and 22 translocation leads to CML (chronic myelogenous leukaemia)
Chromosomal anomaly where there is a de novo error during meiosis
Numerical anomaly
