Passmedicine Genetics Flashcards
Congenital toxoplasmosis features
cerebral calcification
chorioretinitis
Hydrocephalus
Gene associated with CML
ABL
When in embryonic development does the neural tube close?
Week 4
What can detect mutated oncogenes?
PCR
What term is used in genetics to describe conditions with a normal phenotype despite an abnormal genotype?
Low penetrance
McCune-Albright syndrome is due to a random, somatic mutation in what?
GNAS gene
What gene is associated with burkitts lymphoma?
C-MYC
What is fabry disease?
Overview
X-linked recessive
deficiency of alpha-galactosidase A
Features burning pain/paraesthesia in childhood angiokeratomas lens opacities proteinuria early cardiovascular diseas
Intermittent breathing movements start around what week of embryonic development?
10
What is P53?
Tumour suppressor gene located on chromosome 17p. It is the most commonly mutated gene in breast, colon and lung cancer
p53 is thought to play a crucial role in the cell cycle, preventing entry into the S phase until DNA has been checked and repaired. It may also be a key regulator of apoptosis
Heteroplasmy is defined as
presence of more than one type of organellar genome (mitochondrial DNA or plastid DNA) within a cell or individual. It results in variable expression of mitochondrial disease
A 5-year-old boy presents to the clinic with short stature suggestive of achondroplasia. What is the genetic basis of this condition?
Autosomal dominant
What does p53
plays a crucial role in the cell cycle, preventing entry into the S phase until DNA has been checked and repaired
William’s syndrome is caused by what?
microdeletion on chromosome 7
What is vincristine?
dimeric catharanthus alkaloid that acts by binding to tubulin, which disrupts microtubules and blocks metaphase in actively dividing cells.
Burkitt’s lymphoma is commonly associated with what?
C-Myc
Features of Prader-Willi syndrome?
hypotonia during infancy dysmorphic features short stature hypogonadism and infertility learning difficulties childhood obesity behavioural problems in adolescence
Most common cause of down’s syndrome?
Non disjunction
What is p53
Tumpur suppressor gene
Haplo-insufficiency refers to what?
inability of a single allele to confer the usual phenotype to an individual
X-linked recessive conditions means what about male to ,male transmission
There is no male to male transmission
In X-linked recessive inheritance only what sex are affected
X linked
Mitochondrial diseases follows a what pattern?
maternal inheritance pattern
Mitochondria are inherited exclusively from the ovum, and therefore there is no increased risk to the children if only the father has mitochondrial disease.
Polymerase Chain Reaction (PCR) uses what stages?
denaturation, annealing and elongation to amplify a desired fragment of DNA
Erb-B2 (HER2/neu) -
breast and ovarian cancer
What is Expressivity
extent to which a particular genotype is expressed in the phenotype of an individual
What is penetrance?
refers to the proportion of the population who have a particular mutation also having the associated disease. An example would be BRCA-1, a mutation of which causes breast cancer in 80% of those affected, giving it a penetrance of 80%.
What is Pleiotropy
Condition where a single mutation causes more than one observable phenotypic effect. A well known example is PKU
Classic triad of congenital toxoplasmosis =
chorioretinitis, intracranial calcifications, hydrocephalus
This patient is presenting with clinical features consistent with Turner syndrome:
short stature, widely spaced nipples, webbed neck, and high-arched palate
A 54-year-old female presents to see her GP as she has just been diagnosed with breast cancer. The underlying pathology of malignancy involves a failure of apoptosis. Where do the receptors which induce apoptosis occur within cells?
Membrane
Mosaicism is defined as what
Presence of two genetically different populations of cells in the body
Genetic imprinting is defined as what?
difference in phenotype dependent on whether the mutation is maternal or paternal origin
