Genetics: Hodgepodge Flashcards Preview

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Flashcards in Genetics: Hodgepodge Deck (14):
1

Muscular dystrophies

1. Duchenne's
2. Becker
3. Myotonic type 1

2

Duchenne's

X linked FRAMESHIFT mutation
--largest gene= increased risk of SPONTANEOUS MUTATION
Weakness begins in pelvis and moves superiorly
Pseudo hypertrophy of calf muscles (fibrofatty replacement of muscle)
Gower maneuver:
DEATH FROM CARDIOMYOPATHY

3

Becker

X linked recessive due to NONFRAMESHIFT INSERTION in dystrophin gene
Less severe than Duchenne's
Onset early adolescence

4

Myotonic type 1
NOT RECESSIVE DISEASE

AUTO DOM
CTG expansion in DMPK gene
Myotonia, cataracts, testicular atrophy, arrhythmia
"My Tonia, my testicles, my toupee, my ticker"

5

Fragile X syndrome

X linked dominant
Trinucleotide repeat in FMR1 gene
"Xtra large testes, jaw and ears"
Macroorchidism, long face with large jaw, large reverted ears, autism, mitral valve prolapse

6

Trinucleotide repeat expansion diseases

Try hunting for my fried eggs
X girlfriend's first aid helped ace my test
Fragile X - CGG (large testes--lots of circular things)
Friedrich Ataxia - GAA (ataxia--two a's)

Hungtingtons - CAG
Myotonic dystrophy - CTG

7

Down Syndrome

Trisomy 21
Fetal US: increased beta HCG
1. Duodenal atresia
2. Hirshprung's
3. AV septal defect
4. Alzheimer's
5. Increased risk of ALL and AML

8

Edwards Syndrome

Trisomy 18 (election age = 18)
Rocker bottom feet, small jaw
Low set ears, clenched hands with overlapping fingers
Prominent occiput
Death within 1 years of birth

9

Pautau syndrome

Trisomy 13: Puberty = 13
Severe MR, microcephaly, cleft lip/palate, holoprosencephaly, polydactyly
Death within 1 year of life
MIDLINE DEFECTS! (No cut midline)

10

Robertsonian translocation

Long arms of 2 acrocentric chromosomes fuse at the centromere and the 2 short arms are lost
Unbalanced translocation - Down Syndrome and Patau syndrome

11

Cry du chat syndrome

Congenital micro deletion of short arm of chromosome 5 (46 XX or XY)
Microcephaly, MR, high pitched crying, epics that folds, VSD

12

Williams Syndrome

Deletion of long arm of chromosome 7
"Elfin" facies, MR, hypercalcemia, well developed verbal skills, extreme friendliness with strangers, CV problems
"Serena Williams does look like an elf" a very stocky elf...

13

Cystic Fibrosis

Autosomal recessive
Defect in CFTR gene on ch: 7
--misfolded protein
encodes a ATP gated Cl channel -- secretes Cl in lungs and GI tract, reabsorbs Cl
Abnormally thick mucus
1. Recurrent pulm infections
2. Pancreatic insufficiency
3. Infertility
--men: absence of vas deferens
--women: abnormally thick cervical mucus

14

22q11 deletion syndromes

CATCH22
Cleft palate
Abnormal facies
Thymic aplasia
Cardiac defects
Hypocalcemia (parathyroid aplasia)
1. DiGeorge Syndrome: thymic, parathyroid and cardiac defects
2. Velocardiofacial Syndrome: palate, facial, and cardiac defects