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56 Cards in this Set
- Front
- Back
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What is the inheritance of Cystic fibrosis?
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Autosomal recessive
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Gene/Ch defect in CF:
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CFTR gene on Ch' 7 - one more than cystic, one less than fibrosis
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What is the most common deletion on the CFTR gene on Ch' 7 in CF?
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Phe 508
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What is the CFTR protein product/function?
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A Chloride channel that
-Secretes Cl' in GI/lungs -Reabsorbs Cl' from sweat |
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What is the result of defective Cl- channel due to the Phe 508 mutation on the CFTR gene?
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Abnormally thick mucous is secreted that plugs up the lungs, pancreas, and liver.
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What does the plugged up junk lead to - 4 things:
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Recurrent pulmonary infectionn
Chronic bronchitis Bronchiectasis Pancreatic insufficiency |
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What are 2 organisms that are hallmark causes of recurrent pulm infection in CF patients?
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-Staph aureus
-Pseudomonas |
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What is the manifestation of pancreatic insufficiency in CF patients?
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Malabsorption and Steatorrhea
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What do neonates with CF present with?
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Meconium ileus
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What is the diagnostic test for CF?
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Elevated sweat chloride
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What are the X-linked RECESSIVE disorders?
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Be Wise, fool's GOLD has false hope
Bruton's, Wiskott, Fabry, G6pd, Ocular albinism, Lesch nyhan, Duchenne's MD, Hemophilia A/B, Fragile X, Hunter's |
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Why are Female carriers of X-linked Recessive disorders so rarely affected?
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Because of random X inactivation (lyonization)
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What are the 2 types of muscular dystrophies?
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-Duchenne's
-Becker's |
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What is Duchenne's MD gene mutation?
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Frame-shift mutation resulting in DELETION of the Dystrophin gene
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What is Becker's MD gene mutation?
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NOT a deletion - the mutation is less severe than in Duchenne's
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What is the result of deletion of the Dystrophin gene in Duchenne's MD?
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Accelerated breakdown of muscle
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At what age is the typical onset of Duchenne's md?
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Before 5 yo
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What is the anatomical progression of Duchenne's MD?
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Weakness begins in PELVIC GIRDLES and progresses up
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What are 3 hallmark findings in Duchenne's MD patients?
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-Pseudohypertrophy of CALF muscles from fibrofatty replacement of muscle
-CARDIAC myopathy -Gower's sign |
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Gower's sign
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Use upper limbs to help stand up bc lower limbs are too weak
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How is muscular dystrophy diagnosed?
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-Elevated CPK
-Muscle biopsy |
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What are the 3 triple nt repeat diseases to know of?
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-Huntington's
-Myotonic dystrophy -Friedreich's ataxia -Fragile X syndrome |
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How can you remember the tri-NT repeat expansion diseases?
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Try Hunting for My Fried Eggs
-trinucleotide -Huntington -Friedrich -Myotonic dystrophy -Fragile X |
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What feature can any of the Tri-NT repeat expansion diseases show?
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Anticipation - increasing disease severity and earlier onset with successive generations
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What is the gene defect in Fragile X syndrome?
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Defective methylation and expression of the FMR1 gene on the X chromosome
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MAJOR IMPORTANT THING to remember about FRAGILE X SYNDROME:
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#2 cause of MENTAL RETARDATION!!
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What's the #1 cause of mental retardation?
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Downs syndrome
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What is the Triplet of NT's that repeats in Fragile X?
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CGG
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What are the 4 classic findings in patients with Fragile X syndrome?
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Xtra large
-Testes (macroorchidism) -Jaw (long face) -Ears (large/everted Autism - mental retardation |
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What are the 3 important Autosomal trisomies? Which Ch'? Incidence?
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-Downs 21 - 1/700
-Edwards 18 - 1/8000 -Patau 13 - 1/15000 |
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What is Down's syndrome the 'most common' of for 2 things?
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-Most common chromosome disorder
-Most common cause of mental retardation |
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3 findings in utero that are a tipoff to a baby having Downs:
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-LOW AFP in serum/amniotic fluid
-HIGH b-hCG -Increased nuchal TRANSLUCENCY |
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What are the clinical findings on patients with Downs?
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-Simean crease
-Epicanthic folds -Flat Facies |
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What are the physiological manifestations of Down's?
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-Mental retardation
-Duodenal atresia -Congenital heart defects -Alzheimer's in patients >35 |
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What cancer are patients with Down's at increased risk for?
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ALL - acute lymphocytic leukemia
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What is the most common congenital heart defect in Downs patients?
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Septum primum-type ASD - due to endocardial cushion defects
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What are 3 chromosomal abnormalities that can lead to Down's? % of each?
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95% Meiotic nondisjunction of homologous chromosomes
4% Robersonian translocation 1% Mosaicism |
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Which kind is associated with advanced maternal age?
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Only the meiotic nondisjunction form
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What is the incidence of DS in women <20? >45?
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<20 = 1/1500
>45 = 1/25 |
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How does the severity of Edwards and Patau syndrome compare to downs?
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Much more severe - death is usually within the 1st year
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What are the 7 classic findings in EDWARD syndrome/Trisomy 18?
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-SEVERE mental retardation
-Rocker bottom feet -Low set ears -Micrognathia -Congenital heart defects -Clenched hands -Prominent occiput |
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What are the 7 classic findings in PATAU syndrome/Trisomy 13?
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-SEVERE mental retardation
-Microopthalmia (small eyes) -Microcephaly (small brain) -Cleft lip/palate -ABnormal forebrain structures -Congenital heart defects -POLYdactyly |
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So what disease is associated w/
-Syndactyly -Polydactyly |
Syn - Edwards
Poly - Patau |
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What is the Ch' defect that occurs in Cri du chat?
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Deletion of the short arm of Ch' 5!
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So what is the karyotype of an individual with Cri du chat?
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46,xx/xy, 5p-
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What are the hallmark findings in Cri-du-chat syndrome?
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-SEVERE mental retardation
-Microcephaly -Mewing -Epicanthal folds -Cardiac abnormalities |
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CATCH-22
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-Cardiac abnormalities
-Abnormal facies -Thymic aplasia -Cleft palate -Hypocalcemia |
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What is CATCH-22 aka? What is the gene defect?
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DiGeorge syndrome - microdeletion at Ch' 22q11
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Why the hypocalcemia in DiGeorge?
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Parathyroid aplasia
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What does the term "22q11 syndromes" refer to exactly?
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DiGeorge syndrome + Velocardiofacial syndromes
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What is DiGeorge exactly?
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-Thymic
-Parathyroid -Cardiac |
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What is Velocardiofacial syndrome exactly?
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-Palate
-Facial -Cardiac defects |
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What is Fetal Alcohol syndrome caused by?
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Maternal consumption of HIGH amounts of alcohol during pregnancy weeks 3-8
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What are the teratogenic effects of maternal alcohol consumption from weeks 3-8 of embryogenesis?
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-Pre/postnatal Developmental Retardation
-Microcephaly -Face abnormalities -Limb dislocation -Heart/lung fistulas |
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What is a mechanism that causes the congenital defects of FAH?
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Inhibition of CELL MIGRATION
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What is the #1 cause of Congenital Malformations in the US?
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Fetal alcohol syndrome
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