ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: SA-PO577

Rare Cause of Nephrotic Range Proteinuria During Pregnancy: Genetic C3 Nephropathy (C3N) Presenting During Pregnancy

Session Information

  • Genetic Diseases: Diagnosis
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidneys

  • 1102 Genetic Diseases of the Kidneys: Non-Cystic

Authors

  • Fichadiya, Harshil, Rutergs Health Monmouth Medical Center, Long Branch, New Jersey, United States
  • Dua, Richa, Rutergs Health Monmouth Medical Center, Long Branch, New Jersey, United States
  • Bhide, Poorva P., Rutergs Health Monmouth Medical Center, Long Branch, New Jersey, United States
  • Rajamohan, Adhithya, Rutergs Health Monmouth Medical Center, Long Branch, New Jersey, United States
  • Arbes, Spiros M., Rutergs Health Monmouth Medical Center, Long Branch, New Jersey, United States
Introduction

Causes of proteinutria during pregnancy include isolated gestational proteinuria,pre-eclampsia, UTI, pre-exisiting CKD or denovo glomeular disease. We report a case of genetic C3N presenting with new onset proteinuria during pregnancy. C3N is a very rare cause of MPGN and is more commonly seen as an acquired disease due to formation of C3 Nephric factor (autoantibodies against regulatory proteins of complement pathyway) than as inherited disease due to defect in C3 gene leading to abnormal activation of alternate complement pathyway. It is associated with monoclonal gammopathy in elderly.

Case Description

30-year-old Caucasian female presented with pedal and periorbital edema with 3+ proteinuria at the end of first trimester of pregnancy. She had normal BP, no recent infection or vaccination, hisotry of IV drug or medication use, known malignancy, hepatitis of HIV infection, diabetes mellitus, no family history of nephrotic syndrome, negative PLA2R Ab, normal C3, C4 level and no gammopathy disease. UPr/Cr ratio at 21 weeks was 1.6g/mg. At 35 weeks her UPr/Cr. ratio ratio worsened to nephrotic range proteinuria 6.1g. Proteinuria was managed with non pharmacological measures during pregnancy. Postpartum her kidney biopsy revealed MPGN with C3 deposits. Genetic testing revealed pathogenic autosomal dominant variant of C3 gene associated with C3N and atypical HUS and carrier variant of NPHS2 gene. ADAMTS13 level were normal. She was enrolled in a clinical trial at a higher center.

Discussion

To our knowledge this is the first case of genetic C3N presenting during pregnancy. A case of atypical HUS which involves similar gene defect and pathogenesis has been reported in a one month postpartum female. Our patient like a few other cases of C3N presented with nephrotic range proteinuria, hematuria and normal serum complement level. Treatment of mild disease (normal kidney function with proteinuria <1.5g/day) includes supportive measures while moderate to severe disease (proteinuria >1.5g/day and abnormal renal function) includes glucocorticoid and immunosuppression therapy. Trials have reported benefit with eculizumab (C5 inhibitor). Iptacopan (selective factor B inhibitor) is being studied in an ongoing clinical trial. While the genetic disease is autosomal dominant it presents with incomplete penetrance.