Bilateral penetrating keratoplasty for sclerocornea in an infant with monosomy 21. Case report and review of the literature.

An 8-month-old caucasian girl with monosomy 21 and sclerocornea underwent bilateral penetrating keratoplasties. Both light and electron microscopic studies were performed on the corneal buttons. Light microscopy revealed variable and abnormal corneal thickness with the peripheral cornea being thinner than the center, lack of Bowman's layer, irregular stromal lamellae, stromal vascularization, markedly underdeveloped or absent Descemet's membrane, and marked attenuation of the endothelium. Electron microscopy demonstrated basal epithelial cells with a thin epithelial basement membrane residing directly on stromal lamellae without intervening Bowman's layer. Stromal collagen fibrils were irregular in size measuring 38-69 nm in diameter. We believe this to be the first report of corneal transplantation and the second reported case of sclerocornea in a patient with monosomy 21.