# Vitamin K-dependent and other rare coagulation factor deficiencies: a single-center experience

## TL;DR

This study examines rare coagulation factor deficiencies in children, focusing on clinical features, treatment, and outcomes.

## Contribution

The study provides insights into the clinical presentation and management of rare coagulation factor deficiencies in a single-center cohort.

## Key findings

- The most common deficiencies were FVII and FXII, with combined vitamin K-dependent deficiencies in 3 patients.
- Bleeding symptoms varied widely, with oral and nasal mucosal bleeding being most common.
- Prophylactic treatment was used in 27 patients with recurrent bleeding.

## Abstract

Rare coagulation factor deficiency (RFD) is characterized by a deficiency of factor (F) I, FII, FV, FVII, FX, FXI, FXII, FXIII, or a combined deficiency of FV + FVIII or vitamin K-dependent factors and accounts for approximately 5% of all bleeding disorders. The prevalence of RFD in the general population can range from 1 in 1,000,000 for FX to 1 in 2–3 million for FXIII. Combined deficiencies of vitamin K-related factors have been reported in 30 families worldwide. These patients can present with a wide range of clinical symptoms, from mucocutaneous bleeding to life-threatening symptoms such as central nervous system and gastrointestinal bleeding. Treatment of these disorders is primarily based on the replacement of the deficient factor.

In this retrospective study, data from 92 children with RFDs were analyzed to describe the distribution, clinical features, treatment patterns, and outcomes of RFDs.

The most common factor deficiencies were F VII and F XII deficiency and while combined vitamin-K dependent coagulation factor was found in 3 patients. Of the 92 patients included in the study, 72 exhibited bruising and/or bleeding. The most common type of bleeding was oral and nasal mucosal bleeding. Factor activity was ≤ 5% in 22 patients, 6–20% in 12 patients, and 20–50% in the remaining 60 patients. Among patients with factor levels < 5%, there were both patients without bleeding and patients with recurrent cerebral hemorrhage. Similarly, when factor levels reached 50%, some patients experienced bleeding while others remained asymptomatic. Acute and severe bleeding was controlled with treatment in nine patients. Twenty-seven patients with recurrent bleeding symptoms received prophylaxis. RFDs are more common in regions with high rates of consanguineous marriage, which was 29% in our study.

No significant results were obtained regarding an increased risk of bleeding as factor plasmatic levels decreased in patients with RFD. Because of its autosomal recessive inheritance, improving access to genetic counseling and testing is important. Delays in diagnosis and treatment and lack of appropriate prevention are important risk factors that increase life-threatening bleeding.