Thus, FBN1-haploinsufficient Marfan syndrome including our Marfan model pigs may present early onset when the methylation pattern of the FBN1 CpG island shore of the WT allele is accidentally disturbed after birth to a DNA hypermethylation direction, resulting in decreased functional mRNA/protein levels in connective tissues. This evidence concerns the gene FBN1 and Marfan syndrome.