The 2 cases with an in vivo diagnosis of Marfan syndrome were, respectively, carrying: 1) the fibrillin-1 gene missense variant c.5930G>A, which is causing the aminoacidic substitution p.(Cys1977Tyr) in the epidermal growth factor 34 domain of the fibrillin protein; and 2) the fibrillin-1 gene single-nucleotide deletion c.4011delT, which is causing a frameshift p.(Val1338TyrfsTer75), with subsequent premature truncation at the epidermal growth factor-like 22 domain of the fibrillin protein, respectively. The gene discussed is FBN1; the disease is Marfan syndrome.