IEL, a rare inherited connective tissue disorder that can be autosomal dominant (AD) or autosomal recessive (AR), is caused by mutations in the FBN1 (fibrillin-1), LTBP2 (latent transforming growth factor beta-1 binding protein 2) [6], or ADAMTSL4 (a disintegrin and metalloproteinase with thrombospondin motifs) gene. The gene discussed is FBN1; the disease is Alzheimer disease.