Low-frequency inherited complement receptor variants are associated with purpura fulminans.

ABSTRACT: Extreme disease phenotypes can provide key insights into the pathophysiology of common conditions, but studying such cases is challenging due to their rarity and the limited statistical power of existing methods. Herein, we used a novel approach to pathway-based mutational burden testing, the rare variant trend test (RVTT), to investigate genetic risk factors for an extreme form of sepsis-induced coagulopathy, infectious purpura fulminans (PF). In addition to prospective patient sample collection, we electronically screened over 10.4 million medical records from 4 large hospital systems and identified historical cases of PF for which archived specimens were available to perform germline whole-exome sequencing. We found a significantly increased burden of low-frequency, putatively function-altering variants in the complement system in patients with PF compared with unselected patients with sepsis (P = .01). A multivariable logistic regression analysis found that the number of complement system variants per patient was independently associated with PF after controlling for age, sex, and disease acuity (P = .01). Functional characterization of PF-associated variants in the immunomodulatory complement receptors CR3 and CR4 revealed that they result in partial or complete loss of anti-inflammatory CR3 function and/or gain of proinflammatory CR4 function. Taken together, these findings suggest that inherited defects in CR3 and CR4 predispose to the maladaptive hyperinflammation that characterizes severe sepsis with coagulopathy.

New plasma protein C and protein S concentrate: A synergy for therapeutic purposes.

BACKGROUND AND OBJECTIVES: Deficiencies of protein C (PC) or protein S (PS) are rare diseases, characterized by mutations in the PC or PS genes, which encode plasma serine proteases with anti-coagulant activity. Severe PC or PS deficiencies manifest in early life as neonatal purpura fulminans, a life-threatening heamorrhagic condition requiring immediate treatment. First-line treatment involves replacement therapy, followed by maintenance with anti-coagulants. Replacement therapy with specific protein concentrates is currently only limited to PC, and therefore, a PC + PS concentrate represents a useful addition to therapeutic options, particularly for severe PS deficiency. Further, the production of a PC + PS concentrate from unused plasma fractionation intermediates would impact favourably on manufacturing costs, and consequently therapy prices for patients and health systems. MATERIALS AND METHODS: Several chromatographic runs were performed on the same unused plasma fractionation intermediates using different supports to obtain a PC/PS concentrate. The best chromatographic mediums were chosen, in terms of specific activity and recovery. A full process of purification including virus inactivation/removal and lyophilization steps was set up. RESULTS: The final freeze-dried product had a mean PC concentration of 47.75 IU/mL with 11% of PS, and a mean specific activity of 202.5 IU/mg protein, corresponding to over 12,000-fold purification from plasma. CONCLUSION: The development of a novel concentrated PC/PS mixture obtained from a waste fraction of other commercial products could be used for its potential therapeutic role in the management of neonatal purpura fulminans pathology.

Use of hyperbaric oxygen therapy of purpura fulminans in an extremely low birth weight preterm: A case report.

Purpura fulminans (PF) is a rare and fatal complication of septic shock or diffuse intravascular coagulation (DIC) resulting in skin and soft tissue necrosis. PF can be caused by congenital or acquired protein C (PC) or protein S (PS) deficiency. The most common cause of PF in a neonate is sepsis. In our extremely low birth weight preterm case, due to PF that started in the right-hand fingers, examination was made and protein S deficiency was detected as well as MTHFR (A1298C) and Factor V Leiden (R506Q) homozygous mutations. While being unresponsive to fresh frozen plasma (FFP) and unfractionated heparin (UFH) therapy, we want to highlight the curative treatment with hyperbaric oxygen (HBOT), which has not previously been used in extremely low birth weight preterm infants for this purpose.

Clinical and genetic features of Chinese pediatric patients with severe congenital protein C deficiency who first presented with purpura fulminans: A case series study and literature review.

INTRODUCTION: Purpura fulminans (PF) is a hematological emergency that can be caused by severe congenital protein C (PC) deficiency. It has been rarely reported in the Chinese population. We aimed to characterize the clinical and genetic features of Chinese pediatric patients with severe congenital PC deficiency who first presented with PF. MATERIALS AND METHODS: Twelve pediatric patients were diagnosed with severe congenital PC deficiency with PF, which was diagnosed based on our hospital records and previous reports from 1988 to July 2021 in China. We evaluated the clinical and genetic features of these patients. RESULTS: Nine patients (9/12, 75%) had onsets that were observed within the first 48 h after birth. Six patients had a family history of thromboembolism. There was no consanguinity. Other symptoms were intracranial thrombosis or hemorrhage (4, 33.3%), ocular lesions (2, 16.7%), gastrointestinal hemorrhage (2, 16.7%) and kidney infarction before birth (1, 8.3%). All but one of the patients (one case not detected) had a plasma PC activity of <10%. The genetic study indicated that in the eight patients with inherited PC deficiency, two were homozygous, five were compound heterozygous and one was heterozygous for PC deficiency. CONCLUSION: This is the first and largest case series of Chinese pediatric patients with severe congenital PC deficiency who first presented with PF. It has been shown that treatment with both fresh frozen plasma and anticoagulants is recommended when PC concentrate is not easily available, especially in developing countries.

Hereditary protein C deficiency caused by novel compound heterozygous mutants in a Chinese pedigree: A case report.

Purpura fulminans (PF) is a neonatal presentation of homozygous or compound heterozygous protein C (PC) deficiency; infants who are diagnosed with it are determined to have a major defect in coagulation regulation which is associated with undetectable levels of PC. We report a pedigree who suffered from the hereditary PC deficiency with compound heterozygous mutants; genetic analysis revealed compound heterozygous mutations of 262 G > T(Asp88Tyr) and 400 + 5G > A that were identified in the proband; moreover, Asp88Tyr and 400 + 5G > A were also detected in the father and the mother, respectively. A bioinformatics analysis revealed 262 G > T is probably damaging, and structural analysis indicated a possible mechanism for the functional impairment of PC in this pedigree.

Acquired Versus Congenital Neonatal Purpura Fulminans: A Case Report and Literature Review.

Neonatal purpura fulminans (PF) is a life-threatening disorder caused by congenital or acquired deficiencies of protein C (PC) or S. PF presents as a cutaneous manifestation of disseminated intravascular coagulation. We describe a case of PF in a newborn with left leg ischemia and undetectable PC levels soon after birth. Despite anticoagulation therapy and PC concentrate, left foot amputation was required. Genetic testing of PROC for congenital PC deficiency was normal. This case highlights the course of PF due to acquired PC deficiency in a newborn treated with PC concentrate which is rarely described in the literature.

Neonatal Purpura Fulminans, a rare genetic disorder due to protein C deficiency: A case report.

Neonatal Purpura Fulminans is a rare and fatal disorder associated with perivascular haemorrhage and disseminated intravascular coagulation. Early clinical recognition, timely investigation and treatment is utmost important. A 6 days old baby boy was brought to emergency with blackish ulcers all over the body. Initially these were over the feet and scalp but later appeared on the abdomen. On examination, child was vitally stable, mildly icteric and had multiple erythematous large bullous blackish lesions on scalp, lower abdomen, perineum, back and soles. Neonatal reflexes and systemic examination was normal. Laboratory investigations showed normal CBC, PT/APTT and Protein S level while Protein C and Antithrombin III levels were low. Neonatal Purpura Fulminans is a life threatening condition and family screening is also mandatory for early recognition of disease in the siblings.

A novel compound heterozygous mutations in protein C gene causing neonatal purpura fulminans.

: Neonatal purpura fulminans is a rare, life-threatening disease caused by severe congenital deficiency of protein C (PC) because of homozygous or compound heterozygous mutations in the PROC gene. Mutation analysis plays a critical role in diagnosing the disorder and offering prenatal guidance. In this study, we identified a genetic defect in the PROC gene leading to neonatal purpura fulminans. The propositus had very low PC activity (4%) and PC antigen activity (5%). DNA screening of the whole PROC gene revealed two compound heterozygous mutations in exon8 (c.795_796insA) and exon9 (c.1206_1207insG). These two variations led to the compound heterozygous mutations of Gly266Argfs4 and Pro405Alafs20, which were inherited from the patient's father and mother, respectively. His older sister is heterozygous for the Gly266Argfs4 mutation. The inserted nucleotides alter the protein by introducing a stop codon at the subsequent AA position, resulting in a truncated protein compared with the wild type. We deduced that the compound heterozygous mutations are responsible for the PC deficiency, the Gly266Argfs4 mutation has been confirmed to be a novel mutation.

Purpura fulminans mimicking toxic epidermal necrolysis - additional value of 16S rRNA sequencing and skin biopsy.

Both purpura fulminans and toxic epidermal necrolysis (TEN) are rare and life-threatening disorders with a high mortality. We present a case of suspected rapidly progressive, severe pneumococcal sepsis-induced purpura fulminans complicated by multiple organ failure, severe epidermolysis and cutaneous necrosis. We show the diagnostic challenge to differentiate between purpura fulminans and TEN, as the extensive epidermolysis in purpura fulminans may mimic TEN and we highlight the additional value of repeated skin biopsies and 16S rRNA gene sequencing.

Skin Necrosis and Purpura Fulminans in Children With and Without Thrombophilia--A Tertiary Center's Experience.

Purpura fulminans (PF) is a very rare clinicopathologic skin disorder comprising dermal microvascular thrombosis associated with perivascular hemorrhage of multiple origins. It may occur as the presenting symptom of severe congenital deficiency of protein C (PC) or protein S (PS) during the newborn period, or later in life following oral anticoagulant therapy with vitamin K antagonists, or of sepsis that may be associated with disseminated intravascular coagulation. Treatment consists of anticoagulants and PC concentrates during acute episodes. We report our experience in the diagnosis and management of pediatric PF. The medical records of the 6 children aged 2-16 years (median: 5 years) who presented with PF to our tertiary care center between 1996 and 2013 were studied. The thrombophilia workup revealed either the presence of congenital homozygous PC deficiency, prothrombotic polymorphisms (factor V Leiden and FIIG20210A heterozygosity), acquired PC/PS deficiency, or no discernible thrombophilia. The skin necrosis resolved following conservative fresh-frozen plasma/anticoagulant therapy in 2 cases, whereas 3 children required interventional plastic surgery. The sixth case, a 10-year-old child with severe PC deficiency, heterozygous factor V Leiden, and FIIG20210A, received recombinant activated PC. PF in childhood is rare and has multiple etiologies. Understanding of the variable pathogenesis and risk factors will facilitate diagnosis and appropriate clinical management.

Long-term follow-up of homozygote protein C deficiency after multimodal therapy.

Homozygous protein C deficiency is an extremely rare condition presenting in the neonatal period with purpura fulminans, with very high rates of morbidity and mortality. Optimal treatment for this condition is highly complex, poorly understood, and often limited by cost and product supply. We report a child who presented 2 days after birth with purpura fulminans and severe prenatal eye damage, but no cerebral lesions. He was treated with novel multimodal therapy culminating in liver transplant at 3 years of age. The patient is now 12 years of age, well, with blindness as his only long-term deficit.

A novel mutation c.1048A>T at codon 350(Lys>Stop) in PROC gene causing neonatal purpura fulminans.

Purpura fulminans in the neonatal period due to severe congenital protein C deficiency (protein C activity <1 IU/dl) is a rare autosomal recessive disorder. If untreated, it is fatal. Early identification of such patients may be lifesaving. Acquired deficiency of protein C caused by increased consumption as overt disseminated intravascular coagulation (DIC) and severe infection creates a diagnostic dilemma. Mutation analysis plays a critical role in confirming the diagnosis of the disease and offering prenatal diagnosis. In this report, we describe a newborn who presented with purpura fulminans and DIC, molecular analysis showed a novel c.1048A>T transversion in a homozygous state at codon 350 (Lys>Stop) of protein C (PROC) gene. Prenatal diagnosis in subsequent pregnancy was done which revealed the affected fetus had the same mutation in homozygous form.

[Purpura fulminans, venous thrombosis and constitutional thrombophilia in an infant]. / Purpura fulminans et thrombose veineuse compatible avec une thrombophilie constitutionnelle chez un nourrisson.

The association of idiopathic purpura fulminans (PF) and venous thrombosis (VT) seldom reveals constitutional thrombophilia in an infant. We report a case of PF in an 18-month-old infant. Laboratory tests showed disseminated intravascular coagulation (DIVC) with normal rates of C and S proteins and antithrombin. The echo-Doppler examination conveyed venous thrombosis of the lower limbs, while the genetic study showed heterozygous mutation of Factor II (G 20210A). Precocious and multidisciplinary management included frozen fresh plasma supplementation and necrosectomy with skin grafts. The diagnosis and therapeutic problems posed by PF combined with deep venous thrombosis are discussed.

The protein C omega-loop substitution Asn2Ile is associated with reduced protein C anticoagulant activity.

We report a kindred with heritable protein C (PC) deficiency in which two siblings with severe thrombosis showed a composite type I and IIb PC deficiency phenotype, identified using commercial PC assays (proband: PC antigen 42 u/dl, amidolytic activity 40 u/dl, anticoagulant activity 9 u/dl). The independent PROC nucleotide variations c.669C>A (predictive of Ser181Arg) and c.131C>T (predictive of Asn2Ile) segregated with the type I and type IIb PC deficiency phenotypes respectively, but co-segregated in the siblings with severe thrombosis. Soluble thrombomodulin (sTM)-mediated inhibition of plasma thrombin generation from an individual with PC-Asn2Ile was lower (endogenous thrombin potential (ETP) 56 +/- 1% that of ETP determined without sTM) than control plasma (ETP 15 +/- 2%) indicating reduced PC anticoagulant activity. Recombinant APC-Asn2Ile exhibited normal amidolytic activity but impaired anticoagulant activity. Protein S (PS)-dependent anticoagulant activity of recombinant APC-Asn2Ile and binding of recombinant APC-Asn2Ile to endothelial protein C receptor (EPCR) were reduced compared to recombinant wild-type APC. Asn2 lies within the omega-loop of the PC/APC Gla domain and this region is critical for calcium-induced folding and subsequent interactions with anionic phospholipids, EPCR and PS. The disruption of these interactions in this naturally-occurring PC variant highlights their collective importance in mediating APC anticoagulant activity in vivo.

Long-term survival of a child with homozygous protein C deficiency successfully treated with living donor liver transplantation.

Homozygous protein C deficiency is an autosomal recessive disorder often presenting with purpura fulminans. Fresh frozen plasma and oral anticoagulation have been used in the treatment of this disease. Lately, protein C concentrate has become the treatment of choice. However, protein C concentrate is not yet widely available in many countries. We report a six-month-old girl with homozygous protein C deficiency who had suffered from frequent thrombotic episodes. She was successfully treated with living donor liver transplantation. Eight years after the transplantation, she remains symptom free. As described here, the liver transplantation offers an alternative curative treatment for children with homozygous protein C deficiency.