To explore if mutations in FBN3 have some relation with MFS, we analyzed FBN3 allelic variants in twelve Chinese patients with MFS by direct sequencing analysis.
We identified six single nucleotide polymorphisms (SNPs) that have already been reported for FBN3 and five novel mutations including two frameshift mutations (c.
These novel mutations were found in FBN3 of MFS patients only while forty healthy individuals showed none of the mutations indicating that these mutations might be the cause for MFS.
The FBN3 gene is fragmented into 63 exons, transcribed in a 9 kb mRNA that encodes a 2809 amino acid protein which has overall homology of greater than 60% with either FBN1 or FBN2, and contains multiple EGF-hike domains.
We amplified exons 11, 22, 25, 30, 38 and 44 of FBN3 by polymerase chain reaction (PCR) using the primer sequences given in Table 1.
We sequenced exons 11, 22, 25, 38 and 44 in patients and in normal individuals, aligning the sequences from these individuals with standard FBN3 sequence showed different polymorphisms (Table III).
Two new frameshift mutations in exon 25 of FBN3 were also identified.
List of primers for amplification and sequencing of FBN3 gene.
FBN3 is important extracellular matrix macromolecules that perform architectural functions in most connective tissues as FBN1, and it has been proved a cause of Weill- Marchesani syndrome that is caused by the disruption of extracellular matrix macromolecules (Robinson and Godfrey, 2000).
As these SNPs were found in FBN3 of both patients and normal controls, so they may not be responsible for MFS (Uyeda et al.
Except these identified SNPs, we identified five novel mutations in the FBN3 gene, including two frameshift mutations (c.
1642G greater than P was located in the site near the fourth TB domain just before where the isoform of FBN3 start, and the mutation p.