The clinical presentation and genotype of protein C deficiency with double mutations of the protein C gene

Unveiling the enigma: A challenging case of protein C deficiency concealed by fever and epistaxis

Protein C deficiency is a rare genetic disorder caused by mutations in the protein C, inactivator of coagulation factors Va and VIIA gene, affecting approximately 1 in 200-500 individuals. It leads to a hypercoagulable state, increasing the risk of blood clots. Symptoms vary with age, ranging from life-threatening purpura fulminans in neonates to venous thromboembolism, particularly deep vein thrombosis, in adults. A recent case involved a 21-year-old South Asian male presenting with persistent fever, weight loss, epistaxis, abdominal tenderness, and acute pain in the right thigh and leg, raising suspicion of deep vein thrombosis. Tests confirmed deep vein thrombosis in multiple leg veins and a pulmonary embolism. The patient was diagnosed with protein C deficiency and received anticoagulant therapy, thrombolysis, and an inferior vena cava filter. Complications of protein C deficiency include deep vein thrombosis, pulmonary embolism, stroke, and ischemic colitis. Diagnosis involves immunoassays and genetic analysis. Treatment includes heparin followed by anticoagulation therapy with warfarin. In severe cases, an inferior vena cava filter may be implanted. The described case required extensive treatment due to multiple deep vein thrombosis and a pulmonary embolism, with lifelong anticoagulant therapy. Early diagnosis and appropriate management are crucial in young patients with a history of venous thromboembolism to prevent and manage complications associated with protein C deficiency.

Neonatal Purpura Fulminans in a Patient With Arterial Thrombosis and Congenital Renal Agenesis

Neonatal purpura fulminans (PF) is an uncommon skin disorder characterized by acute disseminated intravascular coagulation, tissue necrosis, and small vessel thrombosis. Here, we present a case of a seven-day-old male who was admitted to the Neonatal Intensive Care (NICU) Unit at Gaafar Ibn Auf Tertiary Hospital, in January 2023. He presented with black bullous lesions on the plantar surface of the left foot, deep bluish discoloration over the right buttock and right lower abdomen, and gangrenous changes in the right foot with clear demarcation. Birth history was not significant other than mild pallor and icterus. His blood workup was consistent with severe anemia, thrombocytopenia, elevated prothrombin time, and partial thromboplastin time with decreased protein C and S levels; blood culture yielded no growth. A Doppler ultrasound scan of lower extremities confirmed distal occlusion of the right dorsalis pedis artery. The abdominal ultrasound revealed a free left renal bed and left-sided renal agenesis. We came to a diagnosis of neonatal PF and started administering blood and fresh frozen plasma and subcutaneous heparin injections, but unfortunately, the patient eventually passed away. Hence, we decided to report this case to emphasize the significance of the clinical picture in assisting with early diagnosis, despite limited access to genetic testing. We also want to highlight the importance of a "high index of suspicion" that might be mandatory for better outcomes.

Surgical treatment of traction retinal detachment associated with compound heterozygous congenital protein C deficiency

Purpose

Congenital protein C deficiency leads to a prothrombotic state that may result in potentially sight- and life-threatening thromboembolic attacks. In this report, we report two cases of infants with compound heterozygous protein C deficiency who underwent lensectomies and vitrectomies for the treatment of traction retinal detachments (TRDs).

Observations

One two-month-old and one three-month-old female neonates with leukocoria and purpura fulminans received a diagnosis of protein C deficiency and were referred to ophthalmology. In both cases, the right eye had a total retinal detachment that was considered inoperable, while the left eye had a partial TRD for which surgery was performed. Of the two operated eyes, one resulted in a total retinal detachment, while the other eye has remained stable with no retinal detachment progression three months after surgery.

Conclusions

Compound heterozygous congenital protein C deficiency may lead to the rapid development of severe TRDs with poor visual and anatomical prognoses. Early diagnosis and surgery for the treatment of partial TRDs with low disease activity may help prevent progression towards total retinal detachments in these infants.

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.

Clinical Impact of Heritable Thrombophilia on Neonatal-Onset Thromboembolism: A Nationwide Study in Japan

OBJECTIVE

To clarify the incidence and genetic risk of neonatal-thromboembolism, we conducted a nationwide study exploring the impact of thrombophilia on neonatal-thromboembolism in Japan.

STUDY DESIGN

A questionnaire survey was conducted for perinatal centers in Japan, focusing on the clinical expression, genotype, treatment, and outcome of patients who developed thromboembolism within 28 days of birth from 2014 to 2018.

RESULTS

The estimated incidence of neonatal-thromboembolism was 0.39 cases per 10 000 live births. Intracranial lesions and purpura fulminans occurred in 66 and 5 of 77 patients, respectively. Fifty-eight (75.3%) infants presented within 3 days after birth. Four (5.2%) died, and 14 (18.2%) survived with disability. At the diagnosis, <20% plasma activity of protein C was noted in 16 infants, protein S (in 2), and antithrombin (in 1). Thirteen genetic tests identified 4 biallelic and 5 monoallelic protein C-variants but no protein S- or antithrombin-variants. Protein C-variants had purpura fulminans (P < .01), ocular bleeding (P < .01), positive-family history (P = .01), and death or disability (P = .03) more frequently than others. Protein C-variants were independently associated with disability (OR 5.74, 95% CI 1.16-28.4, P = .03) but not death. Four biallelic variants had serious thrombotic complications of neurologic disability, blindness, and/or amputation. Three monoallelic variants survived without complications. The only protein C-variant death was an extremely preterm heterozygote infant.

CONCLUSIONS

Monoallelic protein C-variants had a higher incidence of neonatal-thromboembolism than biallelic variants. Thrombophilia genetic testing should be performed in the setting of neonatal-thromboembolism and low protein C to identify the underlying genetic defect.

Severe protein C deficiency in a newborn caused by a homozygous pathogenic variant in the PROC gene: a case report

Background

Severe protein C deficiency is a rare and inherited cause of thrombophilia in neonates. Protein C acts as an anticoagulant, and its deficiency results in vascular thrombosis. Herein, we report a case of protein C deficiency with a homozygous pathogenic variant in a term neonate, with good outcomes after proper treatment.

Case presentation

A four-day-old male newborn was transferred to the Seoul National University Hospital on account of dark red to black skin lesions. He was born full-term with an average birth weight without perinatal problems. There were no abnormal findings in the prenatal tests, including intrauterine sonography. The first skin lesion was observed on his right toes and rapidly progressed to proximal areas, such as the lower legs, left arm, and buttock. Under the impression of thromboembolism or vasculitis, we performed a coagulopathy workup, which revealed a high D-dimer level of 23.05 μg/ml. A skin biopsy showed fibrin clots in most capillaries, and his protein C activity level was below 10%, from which we diagnosed protein C deficiency. On postnatal day 6, he experienced an apnea event with desaturation and an abnormal right pupillary light reflex. Brain computed tomography showed multifocal patchy intracranial hemorrhage and intraventricular hemorrhage with an old ischemic lesion. Ophthalmic examination revealed bilateral retinal traction detachments with retinal folds. Protein C concentrate replacement therapy was added to previous treatments including steroids, prostaglandin E1, and anticoagulation. After replacement therapy, there were no new skin lesions, and the previous lesions recovered with scarring. Although there were no new brain hemorrhagic infarctions, there was ongoing ischemic tissue loss, which required further rehabilitation. Ophthalmic surgical interventions were performed to treat the bilateral retinal traction detachments with retinal folds. Molecular analysis revealed a homozygous pathogenic variant in the PROC gene.

Conclusion

Severe protein C deficiency can manifest as a fatal coagulopathy in any organ. Early diagnosis and proper treatment, including protein C concentrate replacement, may improve outcomes without serious sequelae.

Protein C deficiency: Report of a challenging case with recurrent multiorgan thrombosis

Introduction and importance

Protein C deficiency is a rare disorder associated with an increased risk of developing abnormal blood clots. Mild and heterozygous cases are usually asymptomatic and may present with recurrent thrombosis. These recurrent thrombi are usually associated with ischemic stroke or concomitant thrombosis during pregnancy and recurrent miscarriage, but arterial thrombosis is relatively uncommon.

Case presentation

In this case report, we introduce an interesting 21-year-old female patient with a protein C deficiency, which presented with a set of symptoms related to ischemia and thrombosis in several different systems, including the colon, brain, and lower extremities.

Clinical discussion

With the diagnosis of ischemic colitis, she underwent medical treatment with hydration, antibiotics, anticoagulant, and GI rest. She was discharged with a suitable response to medical treatment and good general condition. One month later, the patient presented with right upper limb paresis and speech disorder, and at the same time, he had swelling of the left lower limb. The patient was diagnosed with DVT of the common femoral vein and protein c deficiency and treated appropriately with anticoagulant (heparin 1000 lU/h) and was discharged with oral rivaroxaban after symptoms improved.

Conclusion

In young patients with ischemic colitis without a history of previous surgery, increased coagulation should be considered, including impaired fibrinolysis and impaired microcirculation and inflammatory processes. Protein C deficiency is one of several reasons for thrombotic disorders that should be considered in these people, especially if they have a history of DVT or other vascular thromboses.

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Protein C deficiency is a rare disorder leading to a hypercoagubility state.

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We introduce a young protein C deficiency case with ischemic and thrombotic symptoms.

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A reduced pro C level and a heterozygous mutation were observed in the reported case.

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In young patients with ischemic colitis, increased coagulation should be considered.

Diffuse Intracerebral Hemorrhage in an Infant With a Novel Homozygous Variant Leading to Severe Protein C Deficiency

Protein C is a circulating anticoagulant that inhibits factor Va and VIIIa and promotes fibrinolysis. Compound heterozygous or homozygous variants in the Protein C gene (PROC) lead to severe deficiency of protein C and affected neonates typically present shortly after birth with purpura fulminans. We describe an infant who suffered a diffuse intracranial hemorrhage as a neonate and presented with purpura fulminans as an older infant which led to investigations that were consistent with severe protein C deficiency. We demonstrate subacute findings on neuroimaging and suggest this condition should be considered with neonatal presentations of bilateral intraparenchymal hemorrhage.

Clinical guidance for peripartum management of patients with hereditary thrombophilia

Hereditary thrombophilia is a condition in which individuals are susceptible to the formation of thrombi due to a hereditary deficiency in anticoagulant factors, antithrombin (AT), protein C (PC), or protein S (PS). Many Japanese thrombophilia patients have PS deficiency, especially PS p.K196E (also called as PS Tokushima), which is exclusive to the Japanese population, and thrombosis sometimes occurs during pregnancy. At present, no management guidelines for pregnancy and delivery in thrombophilia patients have been developed. The Study Group for Hereditary Thrombophilia, one of the research groups of blood coagulation abnormalities in the Research Program on Rare and Intractable Diseases supported with the Research Grants of the Ministry of Health, Labour and Welfare Science, has therefore developed this clinical guidance to provide healthcare workers with necessary information on safe pregnancy, parturition and neonatal management, adopting a format of responses to seven clinical questions (CQ). At the end of each answer, the corresponding Recommendation Level (A, B, C) is indicated.

Protein C Gene Mutation in an Older Adult Patient with Clostridium perfringens Septicemia-Related Visceral Vein Thrombosis

A 78-year-old Japanese male with Clostridium perfringens septicemia and cholecystitis was found to have thrombosis in the left branch of intrahepatic portal vein as well as superior mesenteric vein. Visceral vein thrombosis (VVT) in this case was associated with protein C deficiency, due to a heterozygous mutation, p. Arg185Met. Our experience emphasizes that VVT, or other thromboembolic events, may occur in later life, triggered by environmental thrombosis risk factors, together with underlying hereditary protein C gene mutation.

Liver transplantation for congenital protein C deficiency with initial poor graft function: a case report with literature review

Congenital deficiency of protein C (PC) is a rare disease that causes thrombophilia during the neonatal and infantile periods. Despite anticoagulative treatments, purpura fulminans and major vessel thrombosis often occur. We report a 7-year-old girl with congenital PC deficiency who underwent deceased donor liver transplantation (LT) and experienced complications accompanied by initial poor graft function (IPGF). Before LT, she had cerebral and ophthalmic hemorrhage, and seven episodes of purpura fulminans. The operation was successfully performed; however, the liver graft developed IPGF. Hyperammonemia and coagulopathy required continuous hemodiafiltration and infusion of fresh frozen plasma. It took 22 days for PC activity to reach reference levels. The changes in clotting and anticlotting activities in the patient's plasma were revealed using clot waveform analysis and the HemosIL ThromboPath^® assay. PC activity remained normal for 5 years after LT. Even when IPGF occurs, liver function including PC activity can remain normal for a long time after recovery from IPGF. LT can be a curative treatment for congenital PC deficiency.

Severe Protein C Deficiency due to Novel Biallelic Variants in PROC and Their Phenotype Correlation

Severe protein C deficiency due to biallelic PROC mutations is an extremely rare thrombophilia, most commonly presenting during the neonatal period as purpura fulminans. Despite treatment, severe morbidity and mortality are frequent. The current study reports 3 unrelated patients harboring novel homozygous PROC mutations and their clinical phenotypes. We discuss how the cytoprotective activity of protein C and its role in the stabilization of endothelial barriers may account for the unique symptoms of this thrombophilia.

C-terminal residues of activated protein C light chain contribute to its anticoagulant and cytoprotective activities

BACKGROUND

Activated protein C (APC) is an important homeostatic blood coagulation protease that conveys anticoagulant and cytoprotective activities. Proteolytic inactivation of factors Va and VIIIa facilitated by cofactor protein S is responsible for APC's anticoagulant effects, whereas cytoprotective effects of APC involve primarily the endothelial protein C receptor (EPCR), protease activated receptor (PAR)1 and PAR3.

OBJECTIVE

To date, several binding exosites in the protease domain of APC have been identified that contribute to APC's interaction with its substrates but potential contributions of the C-terminus of the light chain have not been studied in detail.

METHODS

Site-directed Ala-scanning mutagenesis of six positively charged residues within G142-L155 was used to characterize their contributions to APC's anticoagulant and cytoprotective activities.

RESULTS AND CONCLUSIONS

K151 was involved in protein S dependent-anticoagulant activity of APC with some contribution of K150. 3D structural analysis supported that these two residues were exposed in an extended protein S binding site on one face of APC. Both K150 and K151 were important for PAR1 and PAR3 cleavage by APC, suggesting that this region may also mediate interactions with PARs. Accordingly, APC's cytoprotective activity as determined by endothelial barrier protection was impaired by Ala substitutions of these residues. Thus, both K150 and K151 are involved in APC's anticoagulant and cytoprotective activities. The differential contribution of K150 relative to K151 for protein S-dependent anticoagulant activity and PAR cleavage highlights that binding exosites for protein S binding and for PAR cleavage in the C-terminal region of APC's light chain overlap.

Plasma phenotypes of protein S Lys196Glu and protein C Lys193del variants prevalent among young Japanese women

Protein S Tokushima (p.Lys196Glu) and two protein C gene variants (p.Arg189Trp, p.Lys193del) are hereditary thrombophilia in Japanese and Chinese populations, respectively; however, their diagnosis by plasma analyses is difficult because of the type II deficiency phenotype. Three gene variant genotypes were examined in young Japanese women (n = 231). Plasma total protein S activity and total protein S antigen levels were measured using a total protein S assay system, protein C and protein S activities by clot-based methods, and protein C and free protein S antigen levels by latex agglutination methods. protein S Tokushima (p.Lys196Glu) and protein C p.Lys193del variants were prevalent among participants with allele frequencies of 1.08 and 0.86%, respectively, whereas any carrier of protein C p.Arg189Trp variant was not identified. The plasma phenotype of the type II deficiency of protein S Tokushima heterozygotes was demonstrated by decreased total protein S activity with a normal total protein S antigen level; however, the protein C activities of protein C p.Lys193del heterozygotes were within reference intervals, whereas their protein C antigen levels were elevated. We compared the diagnostic accuracy of the total protein S activity/total protein S antigen ratio for identifying protein S Tokushima heterozygotes with that of the clot-based protein S activity/free protein S antigen ratio and found that sensitivity and specificity of 100% each was only achieved by the former. Protein S Tokushima and protein C p.Lys193del are prevalent among young Japanese women, and a plasma analysis using the total protein S assay system is more accurate than the clot-based protein S activity/free protein S antigen ratio for diagnosing protein S Tokushima carriers.

Imaging Review of Common and Rare Causes of Stroke in Children

Vascular injury is increasingly recognized as an important cause of mortality and morbidity in children (29 days to 18 years of age). Since vascular brain injury in children appears to be less common than in adults, the index of suspicion for vascular brain injury is usually lower. In this review article, we describe frequent and rare conditions underlying pediatric stroke including cardioembolic, viral, autoimmune, post-traumatic, and genetic etiologies. Furthermore, we provide a neuroimaging correlate for clinical mimics of pediatric stroke. This review highlights the role of multimodal noninvasive neuroimaging in the early diagnosis of pediatric stroke, providing a problem-solving approach to the differential diagnosis for the neuroradiologist, emergency room physician, and neurologist.

Diagnostic challenge of the newborn patients with heritable protein C deficiency

ABSTARCT

OBJECTIVE: The diagnosis of neonatal-onset protein C (PC) deficiency is challenging. This study aimed to establish the neonatal screening of heritable PC deficiency in Japan.

STUDY DESIGN

We determined the changes in plasma activity levels of PC and protein S (PS) in healthy neonates, and studied newborn patients with PROC mutation in the Japanese registry.

RESULT

Physiological PC and PS levels increased with wide range. The PC/PS-activity ratios converged after birth. The PC/PS-activity ratios of 19 patients with biallelic mutations, but not, 9 with monoallelic mutation, were lower than those of 13 without mutation. The logistic regression analyses established a formula including two significant variables of PC activity (cut-off < 10%, odds ratio = 30.0) and PC/PS-activity ratio (cut-off < 0.35, odds ratio = 22.7), with 93% sensitivity and 44% specificity for determining patients with mutation(s).

CONCLUSION

The PC/PS-activity ratio is an effective parameter for the genetic screening of neonatal-onset PC-deficiency in Japanese population.