[Fibrillin-1 gene mutation in Chinese patients with Marfan syndrome and its gene diagnosis by haplotype analysis].

Objective: To 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.

Methods: Nine 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.

Results: In 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.

Conclusion: The combination of mutation analysis and haplotype analysis can provide more evidence for gene diagnosis.