- Molecular analysis of collagen XVIII reveals novel mutations, presence of a third isoform, and possible genetic heterogeneity in Knobloch syndrome. Suzuki, O.T., Sertié, A.L., Der Kaloustian, V.M., Kok, F., Carpenter, M., Murray, J., Czeizel, A.E., Kliemann, S.E., Rosemberg, S., Monteiro, M., Olsen, B.R., Passos-Bueno, M.R. Am. J. Hum. Genet. (2002)