OBJECTIVETo analyze fibrillin-1 (FBN(1)) gene mutation in Chinese patients with Marfan syndrome(MFS) and to make a gene diagnosis by haplotype analysis for MFS.

METHODSNine MFS families were analysed with single strand conformation polymorphism(SSCP) and DNA sequencing. With the use of four primers designed in the flanking sequences of each short-sequence tandem-repeat region in FBN(1) gene, the haplotype-segregation analysis for MFS(B) was performed.

RESULTSIn MFS(A)II(1), PCR-SSCP detected SSCP band alterations in exon 25 of FBN(1) gene; direct sequencing showed a small 13bp deletion, the deleted sequence being gcctctgcaccca at base 3243-3456 of cDNA. This mutation caused a frame-shift which was never seen in any unaffected members of the family, and it was a heterozygous mutation; neither of them was identified in 100 chromosomes from 50 normal control individuals. Haplotype-segregation analysis suggested that the disease was passed from Subject I(2) to Subject II(2), Subject II(3), Subject II(5) with the same allele in MFS B family, the proband's daughter also inherited the allele. These data indicated that MFS(B) family was linked to FBN(1) gene, the proband's daughter was an asymptomatic patient.

CONCLUSIONThe combination of mutation analysis and haplotype analysis can provide more evidence for gene diagnosis.