# Monochorionic diamniotic twin brothers with severe hemophilia A: a case report

## TL;DR

This case report describes twin brothers with severe hemophilia A diagnosed in the neonatal period and successfully managed with prophylactic treatment.

## Contribution

The novelty lies in the early diagnosis and management of severe hemophilia A in monozygotic twins during the neonatal period.

## Key findings

- Both twins had completely absent Factor VIII activity (0.7%) confirming severe hemophilia A.
- Emicizumab prophylaxis was effective in preventing major bleeding events in the first year.
- Early coagulation factor assays were critical for diagnosing hemophilia A in newborns.

## Abstract

Congenital hemophilia A is a recessive inherited hemorrhagic disorder caused by factor VIII (FVIII) deficiency. According to the activity of functional coagulation FVIII, the severity of hemophilia A is divided into three levels: mild, moderate and severe. The characteristic phenotype in hemophilia is the bleeding tendency. Clinical severity depends on the extent of the FVIII deficiency and the first bleeding episode in severe and moderate congenital hemophilia A usually occurs in early childhood. At present, there are few reports on symptomatic severe congenital hemophilia A in the neonatal period.

We describe a pair of monozygotic twin brothers with severe hemophilia A. Patient-related factors, including a birth weight discrepancy of 10%, the need for non-invasive respiratory support due to mild respiratory distress, duration of breastfeeding, and vaccinations, were similar in both twins. Anti-hemorrhagic prophylaxis was carried out after birth with IM vitamin K. Due to the presence of prolonged bleeding at the sampling site after performing EGA (Blood Gas Analysis) and neonatal screening, a coagulation test was carried out and a coagulation factor assay (dosage of activity of factors VII, IX, XI, XII) was performed accordingly: activated partial thromboplastin time (APTT) was prolonged without extended prothrombin time (PT). Factor VIII activity was completely absent (0.7%) in both twins. Hematological consultancy was requested and a diagnosis of severe congenital hemophilia A was established. Emicizumab was started as the primary anti-hemorrhagic prophylaxis, with good response and no major bleeding events in the first year of therapy.

The coagulation system is not fully developed at birth, complicating clinical decision-making and the correct interpretation of coagulation testing. Targeted coagulation profiling and factor assays are mission-critical for newborns from twin pregnancies when a hematological disorder is suspected. Coagulation factor assays are essential to confirm the diagnosis of hemophilia A. An early diagnosis of hemophilia is crucial for the timely initiation of an appropriate management plan.