Deleterious mutations in FBN1, encoding fibrillin 1—a cartilage matrix protein—may be associated with either autosomal dominant tall stature-arachnodactyly-lax joints (Marfan syndrome) or extremely short stature-brachydactyly-stiff joints (acromicric dysplasia, geleophysic dysplasia 2, Weill-Marchesani syndrome 2). The gene discussed is FBN1; the disease is Marfan syndrome.