10: Single Gene Genetic Disorders Flashcards

1
Q

Most common lethal genetic disease in Caucasians

A

CF

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2
Q

What happens in heterozygote carriers of CF?

A

Higher incidence of respiratory and pancreatic disease

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3
Q

Some bacteria that are typical CF pathogens

A
  1. Staphylococcus aureus
  2. Haemophilus influenzae
  3. Pseudomonas aeruginosa
  4. Burkholderia cepacia
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4
Q

Chest radiograph of CF pt

A

Can show bronchiectasis, atelectasis, infiltrates, hyperinflation

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5
Q

How to Dx CF

A
  1. Characteristic phenotype OR Hx CF in sibling OR positive newborn screen
    PLUS
  2. Increased sweat chloride OR 2+ CF mutations OR abnl epithelial nasal ion transport
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6
Q

Galactosemia defect and result

A

Defective galactose-1-phosphate uridyltransferase -> increased galactose -> tissue damage

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7
Q

Lesch-Nyhan

A

Increased intermediate produce and their toxic breakdown products

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8
Q

Single most important preventive measure for pts with a1-antitrypsin deficiency

A

Avoiding cigarette smoking bc it markedly accelerates emphysema

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9
Q

Thalassemias vs sickle cell disease

A

Thalassemia: Mutation in globin gene -> affects amount of globin
Sickle cell disease: mutation in structure of globin molecule

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10
Q

Fibrillin-2 mutation in Marfan’s

A

Rare, causes congenital contractural arachnodactyly

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11
Q

Where are microfibrils involved in Marfan’s found?

A

Aorta, ligaments, ciliary Zonula that support lens

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12
Q

What does increased TGF-B signaling lead to in Marfan’s?

A

Inflammation -> deleterious effects on vascular SM development, increases activity of metalloproteases -> loss of ECM

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13
Q

Serious risks of the three types of Ehler’s Danlos that were studying

A

Classic: diaphragmatic hernia
Vascular: colon and large artery rupture
Kyphoscoliosis: ocular fragility, rupture of cornea, retinal detachment

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14
Q

LDL receptor mutation is the most common cause of FH, but what other two proteins can be mutated to cause it?

A

ApoB, PCSK9

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15
Q

Carrier state for Gaucher + having Neimann-Pick type C increases risk for which two diseases?

A

Carrier of Gaucher: Parkinson’s

Niemann-Pick type C: Alzheimers

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16
Q

How lysosomal enzymes are made and transported

A
  1. Made in ER
  2. Transported to Golgi
  3. Tagged with M6P
  4. Transport out and fuse with lysosomes
17
Q

Link between lysosomal storage diseases and what?

A

Neurodegenerative disorders

18
Q

Primary accumulation vs secondary accumulation in lysosomal storage diseases

A

Primary accumulation: catabolism of substrate is incomplete -> accum in lysosome
Secondary accumulation: impaired autophagy

19
Q

Gm2 gangliosidoses

A

Group fo three lysosomal storage diseases caused by an inability to catabolize Gm2 gangliosides

20
Q

Most common Gm2 gangliosidosis

A

Tay-Sachs

21
Q

Which chromosome (mat or pat) typically expresses Niemann-Pick dz

A

Maternal, paternal usually silenced

22
Q

Cells in Neimann-Pick disease

A

Cells enlarge due to sphingomyelin and cholesterol accum -> foamy cytoplasm + Zebra bodies (lysosomes with concentric lamellations)

23
Q

Cells in Gaucher disease

A

Gaucher cells: distended phagocytes in BM, liver, spleen, LNs, tonsils, thymus, etc. - in bone marrow, causes bone erosion which leads to pathological issues

24
Q

Cytoplasm in Gaucher disease

A

Is fibrillary type cytoplasm -> looks like crumpled tissue paper

25
Q

Mucopolysaccharidoses

A

Deficiencies in enzymes that degrade glycosaminoglycans -> abundant Mucopolysaccharidoses in ground substance of CT

26
Q

Histo of MPS

A
  1. Balloon cells: clear cytoplasm, many vacuoles, swollen lysosomes, PAS+
  2. Lamellated zebra bodies (similar to Niemann-Pick)
27
Q

Sx common to all mucopolysaccharidoses

A

Hepatosplenomegaly, arterial deposits (esp coronary A’s), brain lesions, skeletal deformities, valvular lesions

28
Q

Three major types of glycogen storage disorders and explain them

A
  1. Hepatic: increased storage of glycogen in liver, hypoglycemia
  2. Myopathic: increased glycogen storage in muscles -> muscle cramping, no increase in blood lactate after exercise
  3. Misc: assoc with glycogen storage in many organs and death early in life