SummaryResuscitation of children and neonates with severe or refractory bleeding due to surgery or trauma often requires massive transfusion (MT). Findings from recent studies have led to a better understanding of the complex pathophysiology in massive haemorrhage and the effects of MT on haemostasis. Current management of the massively bleeding adult patient has evolved over the past few decades, shifting to early transfusion of products in a balanced ratio as part of MT protocols (MTPs). Paediatric data on successful management of MT are limited and the optimal transfusion approach is currently unknown, leading to practice variability among institutions, depending on resource availability and patients' needs. Here, we review new important concepts in the biology of massive bleeding and MT, outline important management principles and current practices, and highlight available relevant adult and paediatric data.

Jacobsen syndrome (JS) is a rare contiguous gene disorder characterized by a deletion within the distal part of the long arm of chromosome 11 ranging in size from 7 to 20 Mb. The clinical findings include characteristic dysmorphic features, growth and psychomotor delays and developmental anomalies involving the brain, eyes, heart, kidneys, immune, hematologic, endocrine, and gastrointestinal systems. The majority of cases are due to a terminal deletion of 11q; however interstitial deletions have also been reported. We report on a child with clinical manifestations consistent with JS who had a 2.899 Mb interstitial deletion at 11q24.2-q24.3 which is the smallest interstitial deletion reported so far to our knowledge. This deletion includes the KIRREL3 gene, and given our patient's history of neurocognitive delay and autism spectrum disorder, it raises the possibility that this gene is a candidate for the social and expressive language delay observed in our patient.