QUANTITATION OF FIBRILLIN IMMUNOFLUORESCENCE IN FIBROBLAST-CULTURES IN THE MARFAN-SYNDROME

The Marfan syndrome (MFS) is a heritable connective tissue disorder ma nifested by defects in the skeletal, ocular, and cardiovascular system s. Diagnosis of MFS is based on clinical findings. At present there ar e no laboratory tests for specific determination of this disorder. Def ects in fibrillin, an elastin-associated microfibrillar glycoprotein, are now known to cause the variable and pleiotropic manifestations of MFS. Immunofluorescence studies of skin sections and dermal fibroblast cultures were the first to show this association. Most unequivocal ca ses of the Marfan syndrome exhibited an apparent reduction in fibrilli n immunofluorescence. The prospect of examining patients whose clinica l findings suggest a possible diagnosis of the Marfan syndrome has sti mulated us to attempt quantitation of immunofluorescence. In the study described here we used computer-enhanced image analysis to establish ''normal'' and ''abnormal'' (Marfan) parameters of fibrillin immunoflu orescence in dermal fibroblast cultures. Quantitation of fluorescence from control individuals showed a median of 21%, while the median fibr illin fluorescence in MFS patients was 6% with a confidence interval o f less than or equal to 15%. These findings were statistically signifi cant to p<0.01. It is hoped that these analyses may become a useful ad junct in the clinical diagnosis of MFS.