OKTs Flashcards
what pattern is AD inheritance?
vertical inheritance
what is Marfan Syndrome?
it is an AD condition that presents with dislocation of the lens of the eye
what is a carrier?
it is an individuals that it heterozygous for a recessive condition
what is the phenotypes?
how the genetic change manifest themselves
what shape is mitochondrial DNA?
circular
what is a psuedogene?
it is an evolutionary remnant in the form of a DNA sequence. It resembles a gene elsewhere in the genome closely but has mutations that appear to render it inactive
what is anticipation?
it is increasing severity of inherited disease as it passes down through successive generations
what is the karyotype?
we have 46 chromosomes in ours and it was correctly defined in 1956
what is consanguinity?
it is a aspect of family structure that increases the risk of autosomal recessive inheritance
where does mitchondrial inheritance come from?
maternal
what is the nucleosome?
it is the first level of assemble of the genome into chromatin for gene regulation through chemical modifications - they are units of chromatin containing around 200bp of DNA wound around a histone
what is the role of the centromere?
to separate the p and q or short and long arms of the chromosome
where are okazaki fragments found?
in DNA replication on the lagging strand
what is the exon?
it is the part of the gene whos sequence is represented in mature mRNA
what is a carcinoma?
it is a malignant epithelial tumour
what is the most common type of autopsy?
the coroners autopsy
what is histopathology?
it is the investigation and diagnosis of disease from the examination of tissues
what is degranulation?
it is the release of preformed mediators from mast cells
what is cytopenia?
a reduction in the number of blood cells
what is a dendrocyte?
it is a type of APC
what is the prognosis?
it is the anticipated course of a disease in terms of its cure, remission or fate
what does the suffix penia denote?
lack of
what is pathogenesis?
it is the mechanisms through which the aetiology of a disease produces its clinicopathological effects
what is one of the mechanisms of tissue damage in type III hypersensitivity?
generation of active components of complement factors
how common is selective IgA deficiency?
it is the commonest primary defect of specific immunity in the UK
what is an important characteristic of a type IV hypersensitivity reaction?
delayed
what is the suffix that denotes an increased number of cells?
cytosis
what is aetiology?
it is the study of causes of a disease
what is integral to cell mediated immunity?
cytotoxic surface CD8+ T cells that respond to MHC FIB
what is bronchiecstasis?
it is the widening of the bronchi or of their branches
what is anaplasia?
it is usually in tumours and is the lack of normal differentiated state
what does dys in dysplasia mean?
disordered
what is special about IgG?
it is the only immunoglobulin that is able to cross the placenta
what is granuloma?
it is infectious or foreign material that cannot be degraded or removed and is therefore engulfed in inflammatory tissue
what does the T in T cell stand for?
thymus
what does thymic aplasia result in?
lack of T cells resulting in DiGeorge syndrome
what is SCID?
it is the acronym that is used for severe combined immunodeficiency that is seen in infants where the is a failure of both B and T lymphocyte function
what does meta as a prefix mean?
change from one state to another
what is a polymorphism?
it is a common genetic variant that is present in 1% or more of the population
what is glutamine for by?
the CAG trinucleotide that is involved in some neurodegenerative disorders - anticipation is part of this and is usually polymorphic
what does alternative splicing result in?
increased diversity of gene products
what mutations results in short limbed dwarfism?
a unique activating mutation at position 308 of the fibroblast growth factor receptor 3 - results in a wellknown form of achronoplasia
what is the structure of chromosomes after S phase of cell cycle?
each chromosome comprises two identical sister chromatids
what does Sanger sequencing depend on?
the synthesis of DNA strands in the presence of chain terminators
what does a missense mutation result in?
amino acid substitution
what are examples of sex chromosome aneuploidy?
Klinefelters - 47,XXY
Turners - 45,X
what does a 45,XX-18 have?
monosomy
what is a robertsonian translocation?
it is when the two acrocentric chromosomes are fused - the vestigial short arms of acrocentric chromosomes differ in content from that of other chromosome arms as they contain no indispensable single copy genes
what is inversion?
it is an example of a recurrent mutation that is mediated by recombination between repeat sequences near the tip of the X chromosome and is commonly underlying haemophilia A
what is the result of a genetic bottleneck?
reduced diversity
what is alphoid?
a centromeric DNA repeat family
what is FISH?
it is a cytogenetic technique using DNA probes that examines a single locus
where is the splice acceptor site found?
it is found at the 5’ boundary of all but the first exon in a gene - splice donor and splice sites in the primary RNA transcript are recognised by the splicing machinery - spliceosome
what are dizygotic twins?
non identical
what is a somatic mutation?
it is a non inheritable mutation because cells that have somatic mutations make non identical daughter cells. Provided this mutation occurs early enough in development the mutated cell can make up a large amount of the individual which may cause cancer or mosaicism
what is an association study?
it is a type of genome wide genetic study that is based on a population rather than familial inheritance and is a common approach to identifying the genetic contribution to common disease
what are terminator types of codon in bacteria?
TAG, TGA and TAA
what is LD?
linkage disequilibrium means that alleles on two adjacent genetic loci are not randomly assorted into haplotypes - if they are far apart on chromosome then they will be inherited independently but if they are close then will be coinherited
what is a reciprocal translocation?
two different chromosomes break and exchange material - if there is no loss it is known as balances
what is heritability?
it is the proportion of multifactorial causation of a common disease that can be attributed to genetic factors
what is an oncogene?
a gene whos expression tends to cause or promote cancer development
what does the prefix g mean in mutation descriptions?
genome
what does Williams syndrome result from?
a microdeletion in the elastin ELN gene
what base presents in RNA but not DNA?
uracil
what is a conservative mutation?
it is a substitution of a chemically similar amino acid
when is concordance greater?
when there is a genetic influence then concordance will be greater in identical than non identical twins
what is the chiasm?
it is the site of meitotic recombination that is an essential part of gametogenesis. It is also a source of errors that can result in chromosomal duplications and deletions
what is retinoblastoma?
it is an often hereditary cancer that is predominant in childhood and involves the eye
what happens with the BRCA1 mutation?
women with this mutation have a high chance of developing breast and ovarian cancer
what does polygenic mean
more than one gene contributes to the susceptibility of a disease
what is diptheria caused by?
a bacterial endotoxin
what is commensalism?
it is a symbiotic relationship where one organisms benefits and the other is neither benefiting or harmed
what is the main risk factors for atherosclerosis?
smoking
what is lockjaw?
it is an alternative name for tetanus
what is the final destination for an amniotic emboli?
the lungs
what is necrosis?
it is the process of cell death associated with ischaemia
what type of embolism is associated with many TIAs in the brain?
platelet
what can anaesthetic accidents result in?
neurogenic disruptive shock
what is recanalisation?
it is the process through which new blood vessels form within a thrombus meaning that blood can return to the occluded vessel
what maintains the low pH of the vagina?
bacterial species such as lactobacillus
what are cocci?
they are spherical bacteria
what is portal hypertension associated with?
cirrhosis
what is S. Saprohyticus?
it forms part of the normal flora of the vaginal orifice
what is gangrene?
it is a condition resulting from the infection of ischaemic tissue from anaerobic bacteria
what is mitral stenosis?
it is the pathological cause of raised left atrial pressure in pulmonary hypertension
what are endotoxins?
they are the disease causing lipopolysaccharide components of the outer membrane of bacteria
what species of bacteria is responsible for botulism?
belong to the clostridium species
how can haemorrhagic stroke result?
from ruptures aneurysm
what is tinea capitis?
it is ringworm affecting the scalp
what is an important growth factor released by platelets?
PDGF
what is the common fate of gangrenous toes associated with diabetes?
dry gangrene
what are pyogenic bacteria?
they are organisms that are involved in the formation of abscesses
what are microdeletions?
they are loss of chromosomal segments that are too small to be picked up on metaphase chromosome banding - they are detectable by FISH or aCGH such as in DiGeorge or WIlliams syndromes.
what does haploinsufficient mean?
when a gene will not tolerate the loss of one copy
what is methylation?
it is a DNA modification where the major site is the cytosine residue within a CG dinucleotide
how does a processed gene arise?
through retrotransposition - it is the reverse transcribed copy of mRNA and lacks introns
what is an obligate carrier?
in CL recessive it is a woman who must be a carrier due to her position on the pedigree. It could be a woman with two affected sons or one who is a daughter of an affected father
what is monozygotic?
it is identical twins - the genetic differences between DZ and MZ can show the heritability of a genetic trait
what is decipher?
it is a database of human chromosomal variation and its clinical effects, where a patients genome imbalance can be compared to those of a large number of deposited cases
what is microsatellite instability?
it is hallmark of impaired DNA mismatch repair which is used to allow replication errors to be recognised and put right - if it is impaired then errors can accumulate and cause cancer - deficient must be recognised through changes in size of STRs
what is the initiator codon?
it is the first triplet in the open reading frame of mRNA and is usually AUG which encodes methionine
what is the Knudsen effect?
it describes the inactivation of the TSG following a two step two hit mechanism and is used to describe the inheritance of retinoblastoma
when does a single nucleotide deletion cause a frameshift effect?
in protein coding region as it will truncate or scramble the protein and therefore render it non functional. If it is earlier on then it is much less likely to be tolerated however if it occurs close to the end of an open reading frame then might still produce a functional protein
what is 69XXY karyotype?
it is a triploidy syndrome with an extra set of 23 chromosomes that can be either paternally (diandric) or maternally (digynic) inherited. Digynic very occassionally are live born
`what is the telomere in mammals?
they are specialised structures that form the ends of the chromosome and are synthesised by an enzyme complex telomerase. In humans they are long stretched of repeat sequences of TTAGGG
what is cachexia?
it is an extreme form of systemic atrophy that may be associated with pathological loss of appetite
what is malignant?
it is a tumour that has begun to invade and metastasise
what is pleiomorphism?
it is when there is variation in size, shape and staining of malignant cells and their nuclei
what is Barretts Oesophagus?
it is the condition associated with metaplasia of the oesophagus due to chronic reflux
what is the bone relative to breast and primary lung cancer?
it is the favoured site of haematogenous spread
what is dysplasia?
it is the premalignant change in proliferation and differentiation that is associated with metaplasia
what is transcoelomic spread?
it is the spread of tumour cells across a body cavity such as around the peritoneal cavity
what does anaplastic mean?
it is the word used to describe a population of tumour cells that have become so differentiated that they cell type of origin is impossible to establish
what is metaplasia?
it is the reversible change of one cell type/differentiated state to another
what is the most common type of metastatic spread of tumour cells?
lymphatic
what is standard for blood gas analysis?
arterial samples
what are clonal tumour cells?
population that is derived from a single precursor cell
what can cigarette smoke lead to?
the transformation of pseudostratified ciliated bronchial epithelium to squamous epithelium
what happens to the thymus during normal ageing and why?
size decreases due to atrophy
what is acidosis?
when the blood pH is less than 7.4
what happens to the oxyhaemoglobin curve when pH decreases?
lower affinity so released more easily so shifts to right
what is an epigenetic change?
it is a modification to the genome that does not result in a change to the nucleotide sequence
what is uniparental disomy?
it is when both copies of the chromosome are are from one parents - may be completely without clinical effect or result in significant phenotypes such as Prader-Willi syndrome
what is warfarin?
it is an anticoagulant that shows genetically determined dosage sensitivity
what is Beckwith syndrome?
it is an overgrowth syndrome due to the dysregulation of the IGF2 gene - this is an insulin like growth factor that is important in foetal growth regulation and is encoded by an imprinted gene on 11p15
what regulates gene expression?
modifications to the histone class of protein
what does a deficiency in butyrylcholiesterase or pseudocholinesterase result in?
failure to wake up from an anaesthetic
what isw a CpG island?
it is a cluster of CG nucleotides frequently found near the 5’ end of the gene - increased density where it is normally depleted - usually unmethylated but sometimes can become methylated and change gene transcriptional activity
what does Lynch syndrome result from?
hereditary non polyposis colon cancer - AD disorder due to a defect in any of the several genes involved in post replicative DNA repair
what is the hallmark of lynch syndrome?
microsatellite instability
what is the genetic abnormality behind complete hydatidiform moles ?
androgenesis
what does thiopurine methyltransferase show?
genetic variation in activity that results in toxicity in response to treatment with cytotoxic drugs which result in side effects due to bone marrow supression
what is lyonisation?
the term for X inactivation in females
when are preimplantation genetic tests done?
on in vitro cultured embryos
what are pseudoautosomal regions?
they are small shared regions shared between the X and Y chromosomes - exchange of material occurs in these regions during genetic recombination
what is name for the involuntary movement that is typical in HDD?
chorea
what are imprinted genes?
genes that are monoallelically expresses according to their parent of origin that may change according to stage of development
what is penetrance?
it is the frequency with which an inherited disorder manifests itself within gene carriers and is usually applied to dominant disorders that have incomplete penetrance
what are cytochrome P450 oxidases?
they are enzymes that are encoded by a family of genes and are responsible for metabolising many common drugs - there are many members of the gene family and are polymorphic
what is CVS?
chorionic villus sampling is an invasive method for obtaining tissue of foetal genotype for prenatal diagnostic testing - the alternative is amniocentesis
what is the grade of a tumour?
it is how aggressive a tumour is in terms of how closely it resembles its tissues of origin
what are teratomas?
malignant tumours of germ cells
what is a rhabdomyosarcoma?
it is a malignant tumour of the striated muscles
what is collagen?
it is the most abundant protein in the ECM and the target of MMPs
what is aflatoxin?
it is a potent carcinogen that is produced by a species of aspergillus growing on food
what happens over a lifetime with oestrogen?
exposure accumulates and plays an important role in the risk of developing breast cancer
what is the initial spread of carcinoma cell through?
lymphatic route
what is an angioma?
a benign tumour of the blood vessels
what is a lipsarcoma and a lipoma?
the malignant tumour of adipose tissue
lipoma is benign
what is amplification/?
it is a common mechanism by which a proto-oncogene may become abnormally over expressed
what are promoters?
they are types of carcinogens that are effective at directly or indirectly stimulating the proliferation of cells
what staging method is used in colorectal cancer?
dukes staging method
what is the increased cellular feature in invasion?
motility
what is osteosarcoma?
malignant tumour of the bone
what is intravasation?
the stage at which the metastatic sequence allows access to vascular dissemination
what is meningioma?
benign disease of the meninges
what is stage?
it is the extent to which a tumour has spread
what site of tumours is usually associated with the condition XC?
the skin
in TMN, what do N and M stand for?
N = nodes M = metastasis
what is multiple myeloma?
a malignant disease of the bone marrow
