Theme 2 - Genetic and environmental cause of disease: Part 2 Flashcards

Question

What is a germline mutation?

Answer 1

- present in egg or sperm | - can be inherited

Answer 2

1. Variation that does not alter the DNA content (number of nucleotides is unchanged) e.g single nucleotide replacements 2. variation that results in a net loss or gain of DNA sequence - can be large (whole chromosome) or small (single nucleotide)

Answer 3

DNA sequence variation occurring when a single nucleotide - A,T,C or G - in the genome differs between members of a species (or between paired chromosomes in an individual)

Answer 4

an amino acid change

Answer 5

change of amino acid to a stop codon

Answer 6

the codon for an amino acid is changed, but the same amino acid is still coded for

Answer 7

Mutations causing late onset disease can be more frequent whereas mutations that compromise early development or neonatal health will not persist in a population

Answer 8

the inverse correlation between skin pigmentation and latitude is thought to have been shaped by selective pressures favouring lighter skin to facilitate vitamin D synthesis in regions far from the equator

Answer 9

Different pathogenic variants in a single gene - multiple different phenotypes example - mutation in FGFR3 (fibroblast growth factor receptor 3) can cause many different phenotypes e.g achondroplasia

Answer 10

mutations at multiple genomic loci are capable of producing the same phenotype (ie. a single trait, pattern of traits, or disorder), and each individual mutation is sufficient to cause the specific phenotype independently.

Answer 11

``` Chromosome problems: -chromosome number -chromosome structure -missing or extra chromosomal material Gene problems: -point mutations -single or multi-exon deletions/insertions -repeat expansions ```

Answer 12

Amino acid substitution within same group e.g alanine and leucine

Answer 13

Amino acid substitution to one in a different group e.g phenylalanine and glutamine

Answer 14

AUG - codes for methionine

Answer 15

variants that occurs at the boundary of an exon and an intron (canonical splice site) and therefore impact splicing

Answer 16

increased activity of FGFR3, severely limiting bone growth e.g dwarfism

Answer 17

Slow down the formation of bone by inhibiting the proliferation of chondrocytes

Answer 18

``` class 1: benign class 2: likely benign class 3: variant of uncertain significance class 4: likely pathogenic class 5: pathogenic ```

Answer 19

``` C-coloboma H- heart defect C - choanal atresia R- retarded growth and development G- genital hypoplasia E- ear anomalies ```

Answer 20

large deletions - one or more exons are missing from the dystrophin gene large duplications - one or more axons have extra copies in the dystrophin gene

Answer 21

- williams syndrome | - Di George syndrome

Answer 22

Bigger expansions throughout generations - earlier age of onset

Answer 23

non-identical twins

Answer 24

maternal folic acid supplementation

Answer 25

shrinkage of brain, tangles of B-amyloid protein in nerve fibres of hippocampus

Answer 26

they seek to relate variation in human DNA sequence with a disease or trait

Answer 27

the probability of rejecting the null hypothesis given that it is true - often set at 0.05

Answer 28

non-random association of alleles at different loci in a given population

Answer 29

- genome wide association study - examination of all or most of the genes of different individuals of a particular species see how much the genes vary from individual to individual

Answer 30

The situation where allele and genotype frequencies in a population remain constant from generation to generation in the absence of other evolutionary influences

Answer 31

the frequency of the less common variant in a population

Answer 32

- women with breast cancer may have better responses to cancer treatments that are specifically designed for BRCA positive patients e.g cisplatin - can encourage prophylactic surgery (removes ovaries) - preventative mastectomy

Answer 33

amniocentesis - 17 weeks chorionic villus sampling - 11 weeks NIPD - 10 weeks

Answer 34

- the use of genetic material (DNA, RNA) as a medicine | - introduction of functional genes, in the form of DNA, to replace mutated genes

Answer 35

information about a persons genotype used to tailor medical care to prevent disease

Answer 36

- multigene family of enzymes found mostly in liver - responsible for the metabolic elimination of most drugs currently used - important for converting pro-drugs to their active forms

Answer 37

- DNA is extracted and fluroescently labelled - co-hybridise normal reference DNA and test genomic DNA - both DNAs compete to combine to the same sites - signal is analysed by computer - if signal is less than control its a loss of a chromosome and if its more than control its a gain of a chromosome

Answer 38

A cytogenetic technique that uses a DNA probe to examine a single locus

Answer 39

unbalanced t(4;8) translocation top region of chromosomes. 4 has replaced top region of chr 8 T(4,8) is a highly recombinant region

Answer 40

low muscle tone

Answer 41

- delayed growth and development - charachteristic facial appearance - intellectual disability

Theme 2 - Genetic and environmental cause of disease: Part 2 Flashcards

(66 cards)