The mutational inactivation of both isoforms causes autosomal recessive cutis laxa type 1C (ARCL1C) in humans and an ARCL1C-like phenotype in Ltbp4−/− mice, both characterized by high postnatal mortality and severely affected elastogenesis. This evidence concerns the gene LTBP4 and cutis laxa with severe pulmonary, gastrointestinal and urinary anomalies.