Rolf Ljung

Abstract: Summary.  To investigate disease causing mechanism in haemophilia A patients without detectable mutation. Screening for F8 mutations in 307 haemophilia A patients using: re-sequencing and inversion PCR, reverse transcription (RT-PCR) of mRNA, MLPA analysis, haplotyping using SNP and microsatellite markers. No F8 mutations were detected in 9 of the 307 patients (2.9%) using re-sequencing and inversion PCR. MLPA analysis detected duplication in exon 6 in one patient and RT-PCR showed no products for different regions of mRNA in four other patients, indicating failed transcription. No obvious associations were observed between the phenotypes of the nine patients, their F8 haplotypes and the putative mutations detected. The mutation-positive patients carrying the same haplotypes as the mutation-negative patients show a multitude of different mutations, emphasizing the lack of associations at the haplotype level. VWF mutation screening and factor V measurements ruled out type 2N VWD and combined factor V and VIII deficiency respectively. To further investigate a possible role for FVIII interacting factors the haplotypes/diplotypes of F2, F9, F10 and VWF were compared. The nine patients had no specific haplotype/diplotype combination in common that can explain disease. Duplications and faulty transcription contribute to the mutational spectrum of haemophilia A patients where conventional mutation screening fail to identify mutations.

Abstract: Invasive procedures can be performed safely in children with haemophilia due to the availability of factor VIII/IX for patients without inhibitors. Most guidelines are based on the experiences in adults, but still there is no established consensus on the optimal factor levels or duration of replacement therapy for adults undergoing surgery. Few publications have focused on surgery in children with haemophilia. Children who have developed inhibitors to factor VIII/IX have to be treated with bypassing agents and constitute a group at higher risk for bleeding complications during surgery. The aim of this review is to summarize the experiences and opinions in the literature on replacement treatment of children with haemophilia, with and without inhibitors, during and after surgery, with a focus on the most prevalent clinical situations.