Purpose: To investigate the location and tissue-specificity of the pathologic keratoepithelin (KE) deposition in a patient with a keratoepithelinopathy (KEP), TGFBI/BIGH3-related corneal dystrophy.
Methods: An autopsy was performed in a patient with lattice type I corneal dystrophy (LCDI) after authorization was obtained from the family. Mutation screening in TGFBI/BIGH3 was done on the patient several years ago. Eighteen different tissues or organs, including brain, heart, lung, kidney, liver, lymph nodes, spleen, aorta, esophagus, bone marrow, urinary bladder (including a papillary urothelial carcinoma), samples of a metastatic squamous cell carcinoma, adrenal gland, parathyroid gland, muscle, prostate, and cornea were investigated, and sections from the tissues were labeled with KE2 rabbit TGFBI/BIGH3 antiserum.
Results: The patient, diagnosed with LCDI and Alzheimer's disease, died at 79 years of age from a complicated chronic obstructive lung disease. Mutation analysis showed the classical Arg124Cys mutation in exon 4 of TGFBI/BIGH3, associated with LCDI. Except for the cornea, immunostaining with KE2 antisera did not reveal any deposits in any of the 17 other organs analyzed.
Conclusions: Pathologic deposits caused by KE accumulation were only observed in the cornea and in no other tissue or organ in this patient. These results suggest a cornea-specific mechanism in the aggregation of KE. Further studies need to be done to investigate whether the degradation of mutated KE generates cornea-specific fragments that aggregate or whether the clearing of normal fragments is different in affected corneas, which then leads to aggregation.