Congenital H-ficolin deficiency in premature infants with severe necrotising enterocolitis

While low levels of MBL occur in 10% of Caucasians, H-ficolin deficiency is extremely rare: studies involving over 100 000 adults found no case of H-ficolin deficiency, suggesting it exerts crucial functions for the human immune system. 2 The first report on the so far only patient diagnosed with H-ficolin deficiency was published only recently, 3 describing a patient with repeated infections who presented with H-ficolin deficiency caused by homozygosity of the FCN3+1637delC frameshift mutation. With a gene frequency of 0.01, homozygosity is expected in 1 out of 10 000 individuals. 3 Necrotising enterocolitis (NEC) is an overwhelming inflammatory disease typically occurring in premature neonates, characterised by failure of the host to contain local infection, which results in extensive bowel necrosis. 4 To date, it remains unclear why some infants develop NEC while others do not.