Systemic investigation of keratoepithelin deposits in TGFBI/BIGH3-related corneal dystrophy.
OBJECTIVE
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.
El Kochairi
Ilhem
I
Institut de Recherche en Ophtalmologie, Sion, Switzerland. ilhem.elkochairi.2@unil.ch
Letovanec
Igor
I
Uffer
Sylvie
S
Munier
Francis L
FL
Chaubert
Pascal
P
Schorderet
Daniel F
DF
D000368:Aged; D001120:Arginine; D003315:Cornea / Q000378:metabolism / Q000473:pathology; D003317:Corneal Dystrophies, Hereditary / Q000150:complications / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D003545:Cysteine; D004252:DNA Mutational Analysis; D005091:Exons; D016326:Extracellular Matrix Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications; D014018:Tissue Distribution; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism*; D000099222:betaIG-H3 Protein
D001120:Arginine; D003545:Cysteine; D016326:Extracellular Matrix Proteins; D016212:Transforming Growth Factor beta; D000099222:betaIG-H3 Protein