Cell Biology - W2 Pathology Flashcards
(44 cards)
What is the most common form of dwarfism and what is its patten of inheritance?
- Achondroplasia
- Autosomal Dominant
Explain the mechanism of Achondroplasia.
In this disease, there is an FGFR3 (Fibroblast Growth Factor Receptor 3) mutation. This leads to an inhibited production of Collagen II (restricted chondrocyte proliferation) > inhibited long bone growth.
What does FGFR3 specifically do to bone growth?
It negatively regulates it by having constant activation of the receptor tyrosine kinases, which inhibits chondrocyte proliferation.
What is the pattern of inheritance for Marfan’s Syndrome?
Autosomal Dominant
Explain the mechanism of Marfan’s syndrome.
Marfan’s syndrome has a defect in the Fibrillin gene (FBN1), which is necessary for the function of elastin. This leads to weak elastin tissue.
What are some common clinical presentations of Marfan syndrome?
- Aortic/Mitral Regurgitation
- Retinal detachment, Lens issues
- Arachnodactyly (long limbs & fingers)
- Pectus excavatum (funnel chest)
What is the most common cause of kidney failure in the world?
Diabetic Neuropathy
Explain the mechanism of Diabetic Nephropathy.
With diabetes mellitus, there are gylcosylated changes in the renal basement filter in the kidney (specifically the HSPG’s). HSPGs determine the sieving properties and also inhibit uncontrolled replication of cells attached to the BM.
- Hyperglycemia > downregulation of HSPGs > collagen cross linking
- GBM thickening (increased collagen and decreased HSPGs)
- Expansion/hypertrophy of mesangial matrix
Explain the mechanism of Pemphigus Vulgaris.
In this autoimmune disease (or genetic defect of desmosomal cadherins), there is an attack on the desmosomes. This leads to constant blistering and sores of the skin and mucous membranes.
How does someone treat Pemphigus Vulgaris?
Steroid Therapy
What is the pattern of inheritance for Charcot-Marie-Tooth Neuropathy (CMT Disease)?
X-Linked
Explain the mechanism for CMT Disease?
In this disease, there is a mutation in Connexin 32, which leads to gap junction disfunction in the peripheral neurons.
What is the most common inherited peripheral neuropathy in humans?
CMT Disease
What are three important Connexin mutations?
- Connexin 26: Deafness
- Connexin 32: CMT Disease
- Connexin 50: Blindness
What are some common clinical presentations for CMT disease?
- Progressive degeneration of peripheral nerves
- Muscle weakness and atrophy
- Impairment of deep tendon reflexes
What are some important collagen disorders and what types of collagen are they correlated to?
- Osteogenesis Imperfecta (Collagen I)
- Ehlers-Danlos Syndrome (Collagen 1, 3, 5)
- Alport Syndrome (Collagen 4)
- Goodpasture Syndrome (Collagen 4)
- Epidermolysis Bullosa (Collagen7)
Explain the mechanism of Osteogenesis Imperfecta.
In this disease, there is a defect in collagen I. This leads to a substitution of an invariant glycine that is more deleterious.
What are some common clinical presentations for Osteogenesis Imperfecta?
BITE
B = Bones have multiple fractures I = Eyes have blue sclerae T = Teeth have dental imperfections E = Ears have hearing loss
What type of Osteogenesis is lethal?
Type II
What type of Osteogenesis is deforming?
Type III and mildly so in Type IV.
What is the mildest form of Osteogeneis?
Type I
What autoimmune blistering disease presents itself at 60 yrs old or greater? What does this autoimmune disease attack?
- Bullous Pemphigoid
- Autoantibodies to Hemidesmosomal proteins
What are some common clinical presentations for Ehlers-Danlos Syndrome?
- Connective Tissue Weakness (hyperextensible skin, hypermobile joints)
- Rupture of colon or large arteries
- Varicose veins
Explain the mechanism of Ehler-Danlos Syndrome.
In this disease, there is a defective fibrillar collagen synthesis or structure.
The most common mutation is collagen type 5 (then type 1), but there can also be type 3.
