Objective: To investigate clinical features and analyse defect gene transmission in a severe vWD pedigree.
Methods: Phenotypes of a severe hemorrhagic pedigree including 26 family members of four generations were diagnosed with vWF multimer banding and ELISA. Defective gene transmission among the family members was investigated with a series of RFLP and VNTR loci within vWF gene.
Results: For the proband, plasma vWF:Ag was less than 2%, and multimer banding was negative. Gene analysis showed that she carried 2 different defective vWF haplotypes from her parents. The family members carrying one of the defective haplotypes showed normal or slight decrease of vWF:Ag and normal multimer banding pattern.
Conclusion: 1. The proband could be regarded as a putative compound heterozygote of type 3 vWD. The defect vWF gene carried by heterozygote family members could be compensated by a normal allele. 2. DNA analysis based on polymorphism markers within vWF gene has practical values in genetic consulting of severe vWD pedigrees.