heart complications. The disorder is caused by a mutation in the FBN1 gene. The following DNA sequences show a section of the FBNI gene in an unaffected individual and an individual with Marfan syndrome. Unaffected individual: CCG-CCG-CTT Individual with Marfan syndrome: CGG-CCG-CTT Marfan syndrome is an autosomal dominant disorder, so the mutation that causes it is mutation. According to the DNA sequences shown. Marfan syndrome can be caused by a mutation in the FBNI gene. This mutation is likely a mutation.