DDAVP responsiveness in children with mild or moderate haemophilia A correlates with age, endogenous FVIII:C level and with haemophilic genotype.

In most individuals with moderate/mild haemophilia A, FVIII:C levels increase following DDAVP administration to a haemostatic range, thus avoiding the need for FVIII concentrates. We sought to determine the relationship between responsiveness to DDAVP in boys (<18 years old) with mild/moderate haemophilia and patient age, haemophilic severity and haemophilic genotype. Our cohort consisted of 13 boys with moderate and 61 boys with mild haemophilia who, between them, had 38 different mutations; 21 had unique mutations not shared by any other clinic patient, whereas 53 shared one of 17 mutations with some other clinic patient (included 26 boys with ≥ 1 haemophilic brother). Patient age and endogenous FVIII:C levels were strong predictors of response to DDAVP. Younger patients responded less well to DDAVP and 10 of the 11 patients, when retested at an older age, showed an improved response to DDAVP. Only 1 patient with moderate haemophilia responded to DDAVP, whereas 80% of patients with mild haemophilia responded (including all patients with an endogenous FVIII:C of >0.15 U mL(-1)). Almost all patients with the same mutation had the same response to DDAVP or only a minor discordance in response. Patient's age, disease severity and genotype all are predictors of response to DDAVP.

Dental disease in type 3 Von Willebrand disease: a neglected problem.

Type 3 Von Willebrand disease (VWD) is a rare, severe, autosomal recessive bleeding disorder. In our institution, we follow 17 children with type 3 VWD. We have observed a high prevalence of dental disease in these patients prompting us to undertake a retrospective review of our cohort of patients with type 3 VWD to catalogue the extent of their dental disease. Sixteen of these patients have been assessed by our dentistry department. Five children have undergone minor dental procedures (e.g. restorations, stainless steel crowns) and seven major procedures (e.g. dental extractions, pulpotomies and root canal treatments). These patients have collectively used 85,400 (ristocetin cofactor) IU of Humate-P on dental procedures alone. In addition to the considerable costs of factor are the cost of operating room time, dentists' costs, and the cost of other topical haemostatic agents (e.g. Tisseel) used during their dental procedures. As such there is considerable morbidity and cost from dental disease in these patients that is much higher than what is seen in patients with haemophilia or in the normal paediatric population. We speculate that the combination of these patients having a significant mucosal bleeding disorder together with various socioeconomic factors contribute to the significant degree of dental disease seen in this group of patients. We would suggest that better preventive dental care needs to be provided to these patients to avoid the considerable morbidity and very high burden of dental disease in type 3 VWD.