Mutation in alpha 5 chain of collagen 4, the diagnosis
Ans. is 'a' i.e. Alport's syndrome Alport's syndrome is a hereditary nephritis, characterized byMicroscopic hematuria (first symptom)QDeafness QPathology of Alport's syndromeAlport's syndrome is characterized by diffuse glomerular basement membrane thickening.The basement membrane of the glomerulus is made up of type IV collagen.Type IV collagen consists of six differenta chains i.e.a1and a2 located on chromosome 13 (col A4A1, col A4A4)a3 and a4 located on chromosome 2 (col A 4A3, col A 4A2)a5 and a6 located on chromosome 6 (col A 4A5 col A 4A6)a3 a4 and a5 form collagen network present inGlomerular basement membraneCochleaLens capsuleIn Alport's syndrome there is defect in the synthesis of type IV collagen Q because there is a mutation in the gene encoding a5 chain of collagen type IV (col 4A5)These mutations are heterogenous and affect all domains of a5 chain.Because of these defects the glomerular membrane is thin and on electron microscopy it demonstrates irregular foci of thickening alternating with thinning with pronounced splitting of the lamina densa often with "basket weave appearance Q"Also knowPathogenesis of Good pasture syndromeGood pasture syndrome is an uncommon autoimmune disease, characterized by the presence of circulating autoantibodies targeted against the noncollagenous domain of the a-3 chain of collagen IVQ.These antibodies initiate an inflammatory destruction of the basement membrane in kidney glomeruli and lung alveoli, giving rise to proliferative usually rapidly progressive glomerulonephritis Q and a necrotizing hemorrhagic interstitial pneumonitis Q.Clinical features of Alport's syndromeMicroscopic hematuria QHearing loss Q
Alport's syndrome
Thin membrane disease
Nodular glomerulosclerosis
Good pasture syndrome
Glomerular Diseases