Kidney Week

Abstract: SA-PO1184

Lethal Fetal Congenital Anomalies of the Kidney and Urinary Tract in a Kidney Transplant Recipient Due to Unrecognized PAX2 Variant

Session Information

• Transplantation: Clinical - Complications, Pediatrics, and Multi-Organ Considerations
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Bhatia, Unnati, University of Michigan, Ann Arbor, Michigan, United States

Unnati Bhatia, MD

• Goel, Saurabh K., University of Michigan, Ann Arbor, Michigan, United States

Saurabh K. Goel, MD

• Dakka, Ahmed, University of Michigan, Ann Arbor, Michigan, United States

Ahmed Dakka, MD

• Parasuraman, Ravi K., University of Michigan, Ann Arbor, Michigan, United States

Ravi K. Parasuraman, MD

Introduction

The cause of ESKD in kidney transplant (KT) recipients is unknown in 20–45%. Genetic testing identifies pathogenic variants in 23%, mostly cystic and glomerular diseases. Mutation of Paired Box 2 (PAX2) genes can result in congenital anomalies of kidney and urinary tract (CAKUT). We present a transplant recipient with childhood diagnosis CKD of unknown etiology, whose post-KT pregnancy resulted in lethal fetal CAKUT due to PAX2 mutation.

Case Description

A 37 yo F received a pre-emptive living unrelated KT at age of 18 for ESKD of unknown cause. CKD was diagnosed at 13y with bilateral small echogenic kidneys, with no prior biopsy done. Post-KT course was uncomplicated with stable allograft function. Obstetric history was notable for G5 with 2 normal pregnancies and 1 miscarriage. Subsequent pregnancies were complicated by severe fetal abnormalities. The 4^th pregnancy resulted in fetal demise with bilateral renal agenesis. The 5^th pregnancy was complicated by right renal agenesis and left multicystic dysplastic kidney in the fetus (fig 1). Due to 2 pregnancies with CAKUT, genetic testing of maternal and fetal tissues was pursued, all revealing pathogenic variant of PAX2: c.343 C>T (p.Arg115Ter).

Discussion

PAX2 mutation is an autosomal dominant cause of CAKUT. Phenotypes are variable including renal agenesis, hypodysplasia, vesicoureteral reflux (VUR), ophthalmologic abnormalities, sensorineural hearing loss, CNS malformation, hyperuricemia and rarely congenital heart disease. Our patient likely had CKD because of hypoplasia and probably warranted genetic testing. A definitive diagnosis with subsequent counseling may have prevented pregnancy related fetal morbidity and mortality. Clinicians should be aware of PAX2 mutation related renal disorders when facing patients with early onset CKD, involvement of multiple systems, and/or strong family history of renal disease. Our case shows need for early etiological diagnosis of CKD that would result in genetic counseling and guided clinical management. To our knowledge a similar case has not been reported in literature.

Figure 1 (A) Fetal USG with right renal agenesis (asterisk) and left cystic dysplastic kidney (arrowhead). (B) Three generation pedigree