Sheep anti Human Protein S polyclonal antibody

Background: Thromboembolic events are rare but critical complications in childhood nephrotic syndrome. The veins are more commonly affected, while arterial thrombosis is extremely rare but often life-threatening. Herein, we describe the clinical course of a 10-years-old girl with catastrophic multiple arterial thrombosis at the primary onset of nephrotic syndrome who underwent bilateral above-knee amputation. Case diagnosis/treatment: A previous healthy 10-years-old girl contracted the influenza B virus. Five days later, she suddenly developed severe ischemia in both legs. Physical examination showed eyelid and leg edema, and laboratory tests revealed hypoalbuminemia and acute kidney injury. After undergoing contrast-enhanced computed tomography, the patient was diagnosed with multiple arterial thrombosis (including the bilateral iliac arteries) due to nephrotic syndrome. Despite the performance of surgical thrombectomies, fasciotomy, and systematic heparinization, she required bilateral above-knee amputation. The patient achieved spontaneous remission of nephrotic syndrome, and her renal function fully recovered. There were no findings suggestive of secondary nephrotic syndrome and antiphospholipid syndrome. Her protein C and protein S concentrations were slightly decreased at admission. However, whole-exome sequencing revealed a thrombotic risk variant (T630I) in the PROS1 gene encoding protein S. This missense variant is often reported in patients with thrombosis or protein S deficiency, and may result in a thrombotic predisposition in some situations, such as nephrotic syndrome. Conclusions: Arterial thrombosis is a rare complication; however, it must be considered, especially in patients with new-onset nephrotic syndrome. Early recognition is important for early intervention and prevention of serious sequelae.

Inherited deficiency of protein S constitutes an important risk factor of venous thrombosis. Many reports have demonstrated that causative mutations in the protein S gene are found only in approximately 50% of the cases with protein S deficiency. It is uncertain whether the protein S gene is causative in all cases of protein S deficiency or if other genes are involved in cases where no mutation is identified. The aim of the current study was to determine whether haplotypes of the protein S gene cosegregate with the disease phenotype in cases where no mutations have been found. Eight protein S-deficient families comprising 115 individuals where previous DNA sequencing had failed to detect any causative mutations were analyzed using four microsatellite markers in the protein S gene region. Co-segregation between microsatellite haplotypes and protein S deficiency was found in seven of the investigated families, one family being uninformative. This suggests that the causative genetic defects are located in or close to the protein S gene in a majority of such cases where no mutations have been found.