Genotypic and phenotypic character of Chinese neonates with congenital protein C deficiency: a case report and literature review

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.

The c.1243T>C mutation in the PROC gene is linked with inherited protein C deficiency and severe purpura fulminans

Purpura fulminans is a severe coagulation disorder that often leads to death in neonates. Mutations in the protein C (PROC) gene can cause protein C deficiency, leading to this disorder. This study aimed to investigate a family with a history of coagulopathies, particularly those related to protein C deficiency. The primary objective was to identify any genetic mutations in the PROC gene responsible for the coagulopathies. The study focused on a male neonate with purpura fulminans who ultimately died at 2 months of age. The patient had low protein C activity levels (6%). The entire PROC gene of the patient and his family was analyzed using next-generation sequencing to identify any genetic mutations. Segregation analysis was conducted to determine if the mutation followed an autosomal dominant inheritance pattern. In silico analysis was also conducted to evaluate the pathogenicity of the identified mutation. Analysis revealed a novel homozygous c.1243T>G variant PROC gene. The mutation resulted in a Phe415Val substitution. The mutation was found in at least three generations of the family. Carrier family members had lower protein C activity levels than wild-type homozygotes. Additionally, the mutation may account for the observed reduction in protein C enzyme activity.

Pediatric Retinal Detachment in Homozygous Protein C Deficiency: Genetic and Phenotypic Description of a Single Family

Homozygous protein C deficiency is a rare hypercoagulability disorder. This study describes the ocular manifestations and the genetic background in a family with two affected children. This is a retrospective review of ophthalmic examinations, investigations, genetic testing, and blood work-up of two children with homozygous protein C deficiency from a single family. A family with a positive history of consanguineous marriage was found to have two affected children with homozygous protein C deficiency. Abnormal visual behavior was the presenting symptom. Both children had bilateral total tractional retinal detachments at presentation. Skin manifestations included episodes of discoloration and bruising. Laboratory work-up revealed absent protein C activity. Genetic testing confirmed the presence of a homozygous pathogenic mutation in protein C gene (NM_000312.3: c.1297G>A: p.Gly433Ser). Homozygous protein C deficiency should be considered in the differential diagnosis of early-onset tractional retinal detachment in infancy. Although rare, the ophthalmologist may be the first to encounter the condition, and treatment with protein C replacement or anticoagulants may be life-saving. Examination under anesthesia with fluorescein angiography and laser treatment early in life may be warranted to preserve vision. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:293-296.].

Case Report: Successful Long-Term Management of a Low-Birth Weight Preterm Infant With Compound Heterozygous Protein C Deficiency With Subcutaneous Protein C Concentrate Up to Adolescence

Homozygous/compound heterozygous forms of congenital protein C deficiency are often associated with severe antenatal and postnatal thrombotic or hemorrhagic complications. Protein C deficiency frequently leads to severe adverse outcomes like blindness and neurodevelopmental delay in children and may even lead to death. The most widely used long-term postnatal treatment consists of oral anticoagulation with vitamin K antagonists (e.g., warfarin), which is supplemented with protein C concentrate in acute phases. Subcutaneous infusions have been described in infants mostly from 2 months of age after severe postnatal thrombosis, but not in newborns or premature infants without thromboembolism. We report the first case of a compound heterozygous protein C-deficient preterm infant, born at 31+5 weeks of gestation to parents with heterozygous protein C deficiency (protein C activity 0.9% at birth). We focus on both prenatal and perinatal management including antithrombotic treatment during pregnancy, the cesarean section, and continuous postnatal intravenous and consecutive subcutaneous therapy with protein C concentrate followed by a change of therapy to direct oral anticoagulants (DOACs) (apixaban). We report successful home treatment with subcutaneous protein C concentrate substitution overnight (target protein C activity >25%) without complication up to 12.5 years of age. We propose that early planned cesarean section at 32 or preferably 34 weeks of gestation limits potential maternal side effects of anticoagulation with vitamin K antagonists and reduces fetal thromboembolic complications during late pregnancy. Intravenously administered protein C and early switch to subcutaneous infusions (reaching about 3 kg body weight) resulted in sufficient protein C activity and has guaranteed an excellent quality of life without any history of thrombosis for 13 years now. In older children with protein C deficiency, as in our case, DOACs could be a new therapeutic option.

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.