Elastin - Biochemistry - Medbullets Step 1

                        Overview
                    
                        Structure
                    
                        rich in proline, lysine, glycine
                    
                        unlike collagen, can exist in nonglycosylated forms
                    
                        fibrillin protein binds to tropoelastin to form elastic fibers
                    
                        Marfan's disease is caused by a defect in fibrillin 
                    
                        presentation
                    
                        long extremities including fingers
                    
                        scoliosis
                    
                        myopia and lens dislocations
                    
                        upward (like a martian leaving for outer space)
                    
                        as opposed to a downward dislocation in homocystinuria
                    
                        mitral valve prolapse
                    
                        ↑ for aortic aneurism
                    
                        Function
                    
                        is an elastic protein
                    
                        found in tissues where stretch is needed
                    
                        lungs, dermis of the skin, large arteries, elastic ligaments, vocal cords, ligamenta flava of vertebrae
                    
                        desmosine interchain cross linking between lysine residues gives the protein its elastic stretch
                    
                        degraded by elastase
                    
                        α1-antitrypsin normally inhibits elastase
                    
                        class of protease inhibitors
                    
                        synthesized in the liver
                    
                        excess elastase activity caused by α1-antitrypsin (AAT) deficiency
                    
                        absent α1-globulin peak in serum protein electrophoresis
                    
                        autosomal codominant inheritence
                    
                        presentation
                    
                        panacinar emphysema
                    
                        worsened by smoking
                    
                        early onset
                    
                        smoking without AAT deficiency usually causes centriacinar emphysema
                    
                        cirrhosis
                    
                        Clinical Significance
                    
                        Disease
                    
                        Comments
                    
                        Marfan syndrome
                    
                        Almost exclusively AD
                    
                        Mutation in FBN gene
                    
                        encodes fibrillin-1 gene on chromosome 15
                    
                        Patients are susceptible to aortic disease, MVP, lens dislocation, scoliosis, pectus deformity, arachnodactyly
                    
                        α1-antitrypsin deficiency
                    
                        Autosomal codominant inheritence
                    
                        α1-antitrypsin inhibits elastase
                    
                        Can lead to panacinar emphysema and hepatic disease

Action	Numeric Key	Letter Key	Function Key
Show Bullets		S	Enter (frontside only)
20%	1	N
40%	2	H
60%	3	F	Enter (backside only)
80%	4	E
100%	5	M
Toss	0	T

Clinical Significance
Disease	Comments
Marfan syndrome	Almost exclusively AD Mutation in FBN gene encodes fibrillin-1 gene on chromosome 15 Patients are susceptible to aortic disease, MVP, lens dislocation, scoliosis, pectus deformity, arachnodactyly
α1-antitrypsin deficiency	Autosomal codominant inheritence α1-antitrypsin inhibits elastase Can lead to panacinar emphysema and hepatic disease