Marfan syndrome is an autosomal dominant disorder involving different organ 
systems. Marfan syndrome type 1 (MFS1) is caused by mutations in the FBN1 gene. 
Heterozygosity for mutations in the TGFBR1 or TGFBR2 genes cause Loeys-Dietz 
syndrome (LDS) types 2A and 2B that overlap with MFS1 in their clinical 
features. The phenotype of MFS1 is defined by the Ghent nosology, which 
classifies the clinical manifestations in major and minor criteria. Dural 
ectasia is one of the major criteria for Marfan syndrome but it is rarely tested 
for. We here report 22 novel and 9 recurrent mutations in the FBN1 gene in 36 
patients with clinical features of Marfan syndrome. Sixty patients with 
identified mutations in the FBN1 gene and three patients with mutations in the 
TGFBR1 or TGFBR2 genes were examined for dural ectasia. Forty-seven of the 60 
patients (78%) with MFS1 showed the dural ectasia criterion and 13 (22%) did 
not. Thirty-three (55%) patients were suspected of having Marfan syndrome and 24 
(73%) of them had dural ectasia. Two of the three patients with LDS had dural 
ectasia.