IMMUNOFLUORESCENCE STUDY OF TYPE-IV COLLAGEN ALPHA-CHAINS IN EPIDERMAL BASEMENT-MEMBRANE - APPLICATION IN DIAGNOSIS OF X-LINKED ALPORT-SYNDROME

Objective To detect the distribution of alpha 5(N) chain of collagen o n the glomerular basement membrane (GEM) and epidermal basement membra ne (EBM) in the Chinese Alport syndrome (AS) kindreds and to develop a simple diagnostic alternative method to electronic microscopy for dia gnosis of AS. Methods Four male patients from 4 unrelated families man ifested with hematuria, sensorineural hearing loss and had distinct fa mily history. All patients had the characteristic AS pathologic change s by electron microscopy on their renal biopsy tissues. Three normal s kin samples and 2 normal kidney samples were used as normal controls. Monoclonal antibody-based IF test was performed to examine the alpha 5 (N) NCl domain in EBM of normal controls, S-linked AS patients and the ir parents, and in CBR? of normal controls and AS patients. Results In normal controls as well as the patients' fathers, all the monoclonal antibodies used in EBM and GBM staining showed positive reactions alon g basement membranes in a linear pattern. Characteristically, in AS pa tients there were negative reactions to monoclonal antibodies anti-alp ha 5(N) NCl domain in EBM and anti-alpha 3-5(N) NCl domains in GEM. In patients' mothers, alpha 5(N) chain was distributed segmentally in EB M. Conclusion The staining of alpha 5(N) NCl domain in EBM by IF can b e used to diagnose patients and screen defect-gene carriers of X-linke d AS.