Genetics Flashcards
Which autosomal dominant disease is a/w floppy mitral valve, dissecting aortic aneurysm, berry aneurysm?
Marfan’s syndrome (fibrillin 1 defect)
Which autosomal dominant disease is a/w mitral valve prolapse, liver disease, berry aneurysms?
Autosomal dominant polycystic kidney disease (ADPKD)
Which autosomal dominant disease has neural tumors and pigmented iris hamartomas?
neurofibromatosis type 1
Which autosomal dominant disease has a very strong association with colon cancer
FAP (APC gene)
Which autosomal dominant disease can cause MI before age 20?
Familial hypercholesterolemia (hyperlipidemia type IIa)
Which autosomal dominant disease has hemangioblastomas of the retina/ cerebellum/ medulla?
von-hippel lindau
Which autosomal dominant disease has increased MCHC and hemolytic anemia?
Hereditary spherocytosis
Which autosomal dominant disease has bilateral acoustic schwannomas?
Neurofibromatosis type 2
Which autosomal dominant disease has facial lesions, seizure disorder, cancer risk
Tuberous sclerosis
Which autosomal dominant disease has caudate atrophy and dimentia?
Huntingtons
Which autosomal dominant disease has cystic medial necrosis of the aorta?
Marfans
Which autosomal dominant disease has a defect of the fibroblast growth factor (FGF) receptor 3
Achrondroplasia (a/w advance paternal age)
Which renal lysosomal storage disease is associated with renal failure
Fabry’s disease (dialysis treats renal disease)
What are the only two X linked recessive lysosomal storage disease? What is the mode of inheritance of the others?
Fabry’s and Hunters. Autosomal recessive
What is the most common lysosomal storage disorder
Gaucher’s disease
Which lysosomal storage diseases are associated with an early death (usually by age 3)
Tay-sachs, Niemann-Pick, Krabbe’s disease
Which lysosomal storage disease is a demyelinating disease?
Metachromatic leukodystrophy
How might corneal clouding and mental retardation help distinguish between the mucopolysaccharidoses?
Hurler’s- corneal clouding (+) Mental retardation (+)
Hunter’s- corneal clouding (-) Mental retardation (+)
Scheie’s- corneal clouding (+) Mental retardation (-)
I-cell- corneal clouding (+) Mental retardation (+/-)
Which lysosomal storage disorder is deficient in alpha-L-iduronidase
Hurler’s and Scheie’s (Scheie’s is pretty much just a more mild form of Hurler’s and doesnt have the mental retardation)
Which lysosomal storage disorder is deficient iduronate suflatase
Hunter’s syndrome
Which lysosomal storage disorder is deficient in arylsulfatase A
metachromatic leukodystrophy
Which lysosomal storage disorder is deficient in alpha-galactosidase A
Fabrys (alpha gals Always look Fab)
Which lysosomal storage disorder is deficient in galactocerebrosidase (galactocerebroside accumulation)
Krabbe’s (those who LAC gaLACtocerebrosidase get Krabbe)
Which lysosomal storage disorder is deficient in Beta-glucocerbrosidase (glucocerebroside accumulation)
GaUcher’s (GlUcocerebrosidase deficiency)
Which lysosomal storage disorder is deficient in hexosaminidase?
Tay sachs (tay saX -> heXosaminidase deficiency leads to GM2 ganglioside accumulation)
Which lysosomal storage disorder is deficient in sphingomyelinase (sphingomyelin accumulation)
Niemann-Pick disease (Niemann-Pick(S) the liver and spleen. Hepatosplenomegally. (S) is for spingomyelinase.
Characterized by an accumulation of GM2 ganglioside
Tay sachs
Characterized by accumulation of dermatin sulfate
Hurler’s, Hunter’s and Scheie’s
Which lysosomal storage disorders are particularly common among the Ashkenazi Jews?
Tay-sachs, Niemann-Pick, some form of Gaucher’s disease
Which lysosomal storage disorder has “crinkled paper cytoplasm”?
Gaucher’s disease
What is the differential diagnosis for cherry red spot on the retina?
Tay-Sachs, Niemann-Pick, Central retinal artery occlusion
What is the probability that a female heterozygous for an X-linked disease will pass it on to her son?
50%
What is the probability that a female heterozygous for an X-linked disease that mates with a normal male will have a carrier daughter?
50%
What is the probability that a female carrier of an X-linked disease will have a child with that disease assuming she mates with a normal male?
25%
If aa symbolizes a recessive disease, what is the likelihood that parents Aa and Aa will have a phenotypically normal child?
75%
Cystic fibrosis is an autosomal recessive disorder. Two parents that are heterozygous for cystic fibrosis have a normal, nonaffected child. What is the probability that the child is homozygous normal?
33% (we must remove the heterozygous recessive possibility because we no that this child is phenotypically normal)
Upon examination of a pedigree, you not that both males and females are affected with a disease in every generation. Which genetic disease is this?
Autosomal dominant
What is the frequency of the Aa genotype and the AA genotype if the frequency of a allele A is 0.95
AA = 0.95 x 0.95 = .9025 Aa = 0.95 x 0.05 x 2 = .095
If 49% of a particular population is homozygous for a curly hair gene that is dominant to a straight hair gene, what is the percentage of the population that has curly hair?
p^2 = .49 therefore p = 0.7 Therefore q = 0.3 2 x 0.7 x 0.3 = .42 0.49 (p^2) + 0.42 (2pq) = 0.91 91% of the population has curly hair
Genetic disease that is a/w floppy mitral valve, dissecting aortic aneurysm, berry aneurysm
Marfans (auto dom)
Genetic disease that a/w mitral valve prolapse, liver disease, berry aneurysms
ADPKD
Genetic disease that has hemangioblastomas of the retina/ cerebellum/ medulla
Von Hippel Lindau (auto dom)
Genetic disease that has increased MCHC and hemolytic anemia
Hereditary spherocytosis (auto dom)
Genetic disease that has cafe-au lait spots and soft tissue growths
Neurofibromatosis type 1 (auto dom)
Genetic disease that has macro-orchidism and autism
Fragile X (X linked recessive)
Genetic disease in which endocardial cushion defects are common
Down syndrome
Genetic disease with recurrent pulmonary infections and steatorrhea
Cystic fibrosis (auto recessive)
Genetic disease w/ multiple fractures, easily confused with child abuse
Osteogenesis imperfecta (usually auto dom decrease in type 1 collagen)
Genetic disease is that a/w Alzheimers after age 35
Down syndrome
Genetic disease that prone to bilateral acoustic schwannomas
Neurofibromatosis type 2 (auto dom)
Genetic disease with excess fibrofatty tissue deposits amongst muscle
Duchenne’s Muscular dystrophy (X linked recessive) -> Calf pseudohypertrophy
What is the test used to diagnose cystic fibrosis?
Chloride sweat test (> 60 mEq / L)
What is the difference b/w Southern Blot, Northern Blot, and Western Blot?
SNoW DRoP
Southern blot: DNA sample, DNA probe
Northern blot: RNA sample, DNA probe
Western blot: Protein sample, Antibody probe
Accumulation of GM2 ganglioside
Tay-Sachs
Lysosomal storage disease a/w renal failure
Fabry’s (FabRy’s -> R for renal)
Accumulation of dermatin sulfate
Hurler’s, Hunter’s and Scheie’s
Deficiency of hexosaminidase
Tay sachs (tay saX -> heX)
Two patient have the same mutation on chromosome 15 but have different phenotypic expressions. One patient received the mutation from the father while the other received the mutation from the mother. What is this an example of?
Imprinting (Prader-Willi and Angleman syndromes)
Frequency of CFTR in mutation X in pts with cystic fibrosis is 0.1 Cystic fibrosis can be caused by either mutation X or mutation Y in the CFTR gene. What percentage of cystic fibrosis patients are homozygotes for mutation Y?
X = 0.1 Y = 0.9 -> Y^2 = 81%
