Most Common Form of von Willebrand Disease
Type 1 von Willebrand disease is the most common form, accounting for approximately 75% of all symptomatic cases. 1
Classification of von Willebrand Disease Types
Von Willebrand disease (VWD) is the most common inherited bleeding disorder, affecting up to 1% of the general population. The disease is categorized into three main types:
Type 1: Partial quantitative deficiency of von Willebrand factor (VWF)
- Represents ~75% of all symptomatic VWD cases 1
- Characterized by mild to moderate bleeding symptoms
- Typically responds well to desmopressin
Type 2: Qualitative deficiency of VWF with four subtypes:
- Type 2A: Most common Type 2 variant 1
- Type 2B: Less common than 2A
- Type 2M: Less common than 2A
- Type 2N: Less common than 2A
Type 3: Virtually complete quantitative deficiency of VWF
- Very rare (approximately 1 in 1,000 people) 1
- Associated with severe bleeding symptoms
Acquired von Willebrand Syndrome (AVWS):
- Less common than hereditary forms 1
- Associated with specific medical conditions rather than genetic inheritance
Clinical Significance
The prevalence of different VWD types has important clinical implications:
- Type 1 VWD patients typically present with milder bleeding symptoms compared to Type 3 patients 1, 2
- Bleeding manifestations commonly include:
- Mucocutaneous bleeding (nosebleeds, bruising)
- Bleeding from minor wounds
- Heavy menstrual bleeding in women
- Bleeding following surgery or invasive procedures
Diagnostic Considerations
Accurate diagnosis of VWD type is essential for appropriate management:
- Multiple assays are needed to assess VWF levels and function 3
- Type 1 diagnosis can be challenging due to:
Treatment Approach
Treatment strategies differ based on VWD type:
- Type 1 VWD often responds well to desmopressin 3, 2
- Type 3 VWD typically requires VWF replacement therapy 2
- Women with Type 1 VWD experiencing heavy menstrual bleeding may benefit from hormonal therapies 5, 3
Key Pitfalls to Avoid
- Misdiagnosis is common due to complex diagnostic criteria and variable bleeding symptoms 2
- VWF levels can fluctuate due to blood group, exercise, thyroid hormones, estrogens, and aging 2
- Low VWF levels (30-50 IU/dL) may represent a diagnostic challenge, as not all individuals with these levels experience bleeding symptoms 6
In summary, Type 1 VWD is by far the most common form of von Willebrand disease, representing approximately three-quarters of all symptomatic cases, while Type 2 variants (particularly 2A) account for most of the remaining cases, and Type 3 is extremely rare.