Genetics Flashcards
______ is the presence of multiple, genetically different cell lines within the body
Mosaicism
_______ is the probability that a person with a given genotype will exhibit the corresponding phenotype
Penetrance
______ is the occurrence of multiple, seemingly unrelated phenotypic manifestations in different organ systems, as a result of a SINGLE genetic defect
Pleiotropy
Fragile X syn, Huntington disease, friedreich ataxia, and spinocerebellar ataxia are all examples of disorders caused by genes that contain repeated _______ sequences
TRINUCLEOTIDE
_______ syndrome is an AUTOSOMAL DOMINANT connective tissue disorder that classically affects the cardiovascular and musculoskeletal systems as well as the eyes.
Marfan syndrome
Marfan syndrome is a good example of ________ because there is a difference in phenotype although members of the same family have the same genetic mutation.
VARIABLE EXPRESSIVITY
________ is used to describe an inheritied disease state in which sucessive generations experience earlier onset or increased severity of the disease (e.g. Huntington’s Disease)
GENETIC ANTICIPATION
_______ describes a phenominon in which a disease phenotype can be caused by one of SEVERAL genotypes (e.g. osteogenesis imperfecta can come from mutations in COL1A1 or COL1A2)
GENETIC HETEROGENETIY
_______ is a condition in which multiple sets of genetic information are found in the germ cells producing ova or sperm. It can result in mutations being passed to offspring even if the pt’s somatic cells are unaffected
GERMLINE mosaicism
_________ describes instances when different mutations at the same genetic locus cause similar phenotypes
Allelic Heterogneity
WHEELHOUSE: Name the AUTOSOMAL DOMINANT disorder-head circumference in 90th percentile, mid-face hypoplasia, humeral and femoral shortening. Hands have shortened digits and space between 3rd and 4th digits.
Achondroplasia
Achondroplasia is a point mutation on WHAT GENE?
fibroblast growth factor receptor 3 (FGFR3)
WOW ___% of achondroplaisa mutations occur in the fetus of UNAFFECTED PARENTS…its USUALLY the meternal OR paternal allele???
90%…paternal
Wow, I was way off..________ is a rare X LINKED genetic condition that results in a defect in the signal transduction molecule known as Bruton’s tyrosine kinase (BTK)
Bruton AGAMMAGLOBULINEMIA
In Bruton Agammaglobulinemia, what cells cannot mature and leave the bone marrow?
B cells (Bruton = B Cells)
BOOM. YOU READY FOR SOME SHIT: 3 common diseases associated with chormosome 7. GO
1.Cystic Fibrosis 2.Ehlers-Danlos Syndrome 3.Osteogenesis Imperfecta
2 common diseases associated with chromosome 16. GO.
1.polycystic kidney disease 2.tuberous sclerosis
1 common disease associated with chromosome 20. GO.
type I diabetes
1 common disease associated with chromosome 22. GO
DiGeorge syndrome
This SHOULD be wheelhouse…get it there-Early onset osteoporosis, scoliosis, blue sclera of the eye, and hearing loss…WHAT GENE AND PROTEIN PRODUCT ARE INVOLVED??
OSTEOGENESIS IMPERFECTA…COL1A1 and COL1A2 for type I collagen (I LOVE how they name genes!)
Activation of the ____ proto-oncogene which occurs in MEN2 syndrome is an example of an ACTIVATING mutation that predisposes to malignancy. ONLY 1 copy of a proto-oncogene is sufficient to promote tumor development!!!
RET
What cancer is associated with fusion of 2 genes to form a novel protein? In this case, its between chromosomes 9 and 22 (AKA PHILADELPHIA chromosome)
CML (chronic myeloid leukemia)
The mechanism behind MOST heritable cancer syndromes-including Li-Fraumeni Syndrome- is a SINGE _____ cell aquiring a “second hit” and developing a second inactivating mutation in the remaining copy.
SOMATIC
In an X-linked Recessive disorder, what are the chances a duaghter will be a CARRIER? What are the chances a son is AFFECTED?
BOTH are a 1/2 chance
What type of genetic disorder (AD, AR, X-linked, etc.) is DUCHENNE Muscular Dystrophy?
X-linked Recessive
What is the name for the sign when a boy with DUCHENNE Muscular Dystrophy, aged 3-5 y/o, begins to use his hands as support when they rise from the floor?
GOWER’s sign
What deficiency is an X-Linked deficiency most common among African, Asian, or Mediterranian decent and caused hemolysis and acute-onset anemia?
G6PD (Glucose-6-Phosphate Dehydrogenase) deficiency
Alpha-thalassemia is characterized by impaired ________
HEMOGLOBIN SYNTHESIS
Which disease is due to a deficiency in BETA-glucoCERE-BRO-sid-ase?
Gaucher disease
What is the electron microscopy appearance of GAUCHER disease? What type of inheritance is it?
“wrinkled tissue paper”…Autosomal Recessive
Glucose-6-phosphatase deficiency causes _______ disease…it is of _______ inheritance
von Gierke…
TAY-SACHS disease is a __________ deficiency…it is of _______ inheritance
hexos-aminidase A deficiency…Autosomal recessive
NEIMANN-Pick is a ________ deficiency and is of _______ inheritance
Sphingo-myelin-ase deficiency….Autosomal Recessive
ERBB2 is an epidermal growth factor receptor that is overexpressed in ________
breast cancer
______ genes are KEY regulatory genes for EYE and BRAIN development
PAX (Paired Box)
____ is a tumor supressor gene MUTATED in Li-Fraumeni syndrome which is associated with breast cancer and sarcomas at a young age
TP53
_______ syndrome occurs due to an autosomal dominant mutation of mismatch repair genes leading to microsatellite instability…What are the 3 most common neoplasms associated with this condition?
LYNCH…1.Colorectal Cancer 2.Endometrial Cancer 3. Ovarian Cancer
This one was tricky…what is the other autosomal recessive disorder that has very similar manifestations to MARFAN Syndrome, BUT also has intellectual disability and DOWNWARD lens dislocation?
HOMO-CYSTIN-URIA
Influenza pandemics are typically the result of _______ shift, caused by GENETIC REASSORTMENT of H and N proteins on the influenza A (ORTHOMYXOVIRUS) virus.
ANTI-GENIC shift
McArdle disease is an autosomal recessive disease that presents with exercise intolerance. Its a deficiency in muscle _____ _______, which DEGRADES GLYCOGEN into glucose-1-phosphate subunits
GLYCOGEN PHOSPHORYLASE
Cystic HYGROMAS are most commonly associated with CHROMOSOMAL _________
A-NEU_PLOIDY (turner or trisomies)
INTERESTING!! _______ inactivation occurs when an unequal raitio of genes are expressed on a females 2 X chromosomes. A possible outcome of this is even if a female is HETEROZYGOUS for an X-linked disorder-like hemophila-they can still express the disorder.
SKEWED X INACTIVATION
Monosomy X is the most common cause of _______ syndrome
Turner
________ ________ is an autosomal recessive disease characterized by the failure of the NUCLEOTIDE EXCISION REPAIR and therefore susceptibility to cutaneous malignancies. Tx is AVOIDANCE of UV light
Xerodoma Pigmentosum (XP)
Li Fraumeni Syndrome results from defects in the ____ tumor suppressor gene and therefore pts are at risk for developing breast cancer and soft tissue sarcomas
p53
Prader-Willi syndrome occurs due to a loss of PATERNAL expression of a critical region of chromosome ___
15
________ _______ is an error that occurs during MITOTIC division resulting in offspring with 2 copies of a chromosome from ONE parent
UNIPARENTAL DISOMY
