Genetics

Question 1

______ is the presence of multiple, genetically different cell lines within the body

Answer 1

Mosaicism

Question 2

_______ is the probability that a person with a given genotype will exhibit the corresponding phenotype

Answer 2

Penetrance

Question 3

______ is the occurrence of multiple, seemingly unrelated phenotypic manifestations in different organ systems, as a result of a SINGLE genetic defect

Answer 3

Pleiotropy

Question 4

Fragile X syn, Huntington disease, friedreich ataxia, and spinocerebellar ataxia are all examples of disorders caused by genes that contain repeated _______ sequences

Answer 4

TRINUCLEOTIDE

Question 5

_______ syndrome is an AUTOSOMAL DOMINANT connective tissue disorder that classically affects the cardiovascular and musculoskeletal systems as well as the eyes.

Answer 5

Marfan syndrome

Question 6

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.

Answer 6

VARIABLE EXPRESSIVITY

Question 7

________ 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)

Answer 7

GENETIC ANTICIPATION

Question 8

_______ 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)

Answer 8

GENETIC HETEROGENETIY

Question 9

_______ 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

Answer 9

GERMLINE mosaicism

Question 10

_________ describes instances when different mutations at the same genetic locus cause similar phenotypes

Answer 10

Allelic Heterogneity

Question 11

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.

Answer 11

Achondroplasia

Question 12

Achondroplasia is a point mutation on WHAT GENE?

Answer 12

fibroblast growth factor receptor 3 (FGFR3)

Question 13

WOW ___% of achondroplaisa mutations occur in the fetus of UNAFFECTED PARENTS…its USUALLY the meternal OR paternal allele???

Answer 13

90%…paternal

Question 14

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)

Answer 14

Bruton AGAMMAGLOBULINEMIA

Question 15

In Bruton Agammaglobulinemia, what cells cannot mature and leave the bone marrow?

Answer 15

B cells (Bruton = B Cells)

Question 16

BOOM. YOU READY FOR SOME SHIT: 3 common diseases associated with chormosome 7. GO

Answer 16

1.Cystic Fibrosis 2.Ehlers-Danlos Syndrome 3.Osteogenesis Imperfecta

Question 17

2 common diseases associated with chromosome 16. GO.

Answer 17

1.polycystic kidney disease 2.tuberous sclerosis

Question 18

1 common disease associated with chromosome 20. GO.

Answer 18

type I diabetes

Question 19

1 common disease associated with chromosome 22. GO

Answer 19

DiGeorge syndrome

Question 20

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??

Answer 20

OSTEOGENESIS IMPERFECTA…COL1A1 and COL1A2 for type I collagen (I LOVE how they name genes!)

Question 21

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!!!

Answer 21

RET

Question 22

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)

Answer 22

CML (chronic myeloid leukemia)

Question 23

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.

Answer 23

SOMATIC

Question 24

In an X-linked Recessive disorder, what are the chances a duaghter will be a CARRIER? What are the chances a son is AFFECTED?

Answer 24

BOTH are a 1/2 chance

Question 25

What type of genetic disorder (AD, AR, X-linked, etc.) is DUCHENNE Muscular Dystrophy?

Answer 25

X-linked Recessive

Question 26

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?

Answer 26

GOWER’s sign

Question 27

What deficiency is an X-Linked deficiency most common among African, Asian, or Mediterranian decent and caused hemolysis and acute-onset anemia?

Answer 27

G6PD (Glucose-6-Phosphate Dehydrogenase) deficiency

Question 28

Alpha-thalassemia is characterized by impaired ________

Answer 28

HEMOGLOBIN SYNTHESIS

Question 29

Which disease is due to a deficiency in BETA-glucoCERE-BRO-sid-ase?

Answer 29

Gaucher disease

Question 30

What is the electron microscopy appearance of GAUCHER disease? What type of inheritance is it?

Answer 30

“wrinkled tissue paper”…Autosomal Recessive

Question 31

Glucose-6-phosphatase deficiency causes _______ disease…it is of _______ inheritance

Answer 31

von Gierke…

Question 32

TAY-SACHS disease is a __________ deficiency…it is of _______ inheritance

Answer 32

hexos-aminidase A deficiency…Autosomal recessive

Question 33

NEIMANN-Pick is a ________ deficiency and is of _______ inheritance

Answer 33

Sphingo-myelin-ase deficiency….Autosomal Recessive

Question 34

ERBB2 is an epidermal growth factor receptor that is overexpressed in ________

Answer 34

breast cancer

Question 35

______ genes are KEY regulatory genes for EYE and BRAIN development

Answer 35

PAX (Paired Box)

Question 36

____ is a tumor supressor gene MUTATED in Li-Fraumeni syndrome which is associated with breast cancer and sarcomas at a young age

Answer 36

TP53

Question 37

_______ 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?

Answer 37

LYNCH…1.Colorectal Cancer 2.Endometrial Cancer 3. Ovarian Cancer

Question 38

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?

Answer 38

HOMO-CYSTIN-URIA

Question 39

Influenza pandemics are typically the result of _______ shift, caused by GENETIC REASSORTMENT of H and N proteins on the influenza A (ORTHOMYXOVIRUS) virus.

Answer 39

ANTI-GENIC shift

Question 40

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

Answer 40

GLYCOGEN PHOSPHORYLASE

Question 41

Cystic HYGROMAS are most commonly associated with CHROMOSOMAL _________

Answer 41

A-NEU_PLOIDY (turner or trisomies)

Question 42

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.

Answer 42

SKEWED X INACTIVATION

Question 43

Monosomy X is the most common cause of _______ syndrome

Answer 43

Turner

Question 44

________ ________ 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

Answer 44

Xerodoma Pigmentosum (XP)

Question 45

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

Answer 45

p53

Question 46

Prader-Willi syndrome occurs due to a loss of PATERNAL expression of a critical region of chromosome ___

Answer 46

15

Question 47

________ _______ is an error that occurs during MITOTIC division resulting in offspring with 2 copies of a chromosome from ONE parent

Answer 47

UNIPARENTAL DISOMY