THE PATHOLOGY OF CORNEA IN TANGIER DISEASE (FAMILIAL HIGH-DENSITY-LIPOPROTEIN DEFICIENCY)

Aims-To clarify the underlying causes of corneal opacification in Tang ier disease. Methods-Both corneas were removed at death from a 62 year old man with Tangier disease, and were examined by direct and transmi ssion electron microscopy, histochemistry, biochemical analysis by thi n-layer and gas-liquid chromatography after extraction, and by differe ntial scanning calorimetry. Results-Membranous inclusions in the strom a were seen on transmission electron microscopy. Direct analysis confi rmed enrichment with phospholipids and cholesterol, with acyl patterns and proportions as ester broadly similar to those of normal cornea. T angier cornea showed major thermotropic phase transitions in the range 28-37 degrees C, peak 30-33 degrees C, extending above profiles of no rmal clear cornea and without the complexity of those seen with cornea with heavy arcus involvement. Conclusions-Lipid accumulation underlie s corneal opacification in Tangier disease. The excess material is mai nly phospholipid and cholesterol esters. As at other sites which are b elow body core temperature, notably tonsil, accumulation may be enhanc ed by local impaired mobilisation of material as the phase transitions of the excess lipid present extend above ambient corneal temperatures .