Molecular study of the fibulin-5 (FBLN5) gene in a large consanguineous Turkish family with four patients affected by AR cutis laxa type I demonstrated the presence of a homozygous missense mutation (T998C) in the FBLN5 gene resulting in a serine-to-proline (S227P) substitution in the fourth calcium-binding epidermal growth factor-like domain of fibulin-5 protein.