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Kidney Week

Abstract: TH-PO394

Bilateral Renal Cysts and CKD in Association With Neurofibromatosis

Session Information

Category: Genetic Diseases of the Kidneys

  • 1101 Genetic Diseases of the Kidneys: Cystic

Authors

  • Bugazia, Seif, Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Schimmenti, Lisa A., Mayo Clinic Minnesota, Rochester, Minnesota, United States
  • Hogan, Marie C., Mayo Clinic Minnesota, Rochester, Minnesota, United States
Introduction

Neurofibromatosis with CKD has rarely been reported. Cases lack description of kidney phenotype. Renal gene panels do not evaluate the NF2 gene.

Case Description

A 67yo male was referred with CKD & bilateral renal cysts, bilateral sensorineural hearing loss, tinnitus & balance difficulty. He used a hearing aid to his left & was deaf in his right ear. He had bilateral cataracts & cataract surgery, bilateral vestibular schwannomas & a dural-based meningioma treated with gamma knife and bevacizumab (d/c'ed due to side effects). Lumbar, thoracic & cervical MRI imaging showed no schwannomas. MRI (fig.1) revealed bilateral kidney cysts (total kidney vol= 1257ml). Functional studies revealed a functioning right & non-functional left kidney. Whole exome renal panel (custom >150 genes) to determine the cause of cystic renal disease was unrevealing. We next performed next generation sequencing using a schwannomatosis panel revealing NF2: c. 1396C>T, with a mosaic truncating pathogenic variant in NF2, encoding a premature stop codon, p.Arg466Ter, in Exon 13 (variant allele fraction 2%, 28 variant reads/ 1112 wild type reads, both strands of 4 amplicons, Q score:36) & confirimed by High Resolution Melting Curve Analysis.

Discussion

We describe bilateral cystic disease in a NF2 patient with CKD. Individuals with mosaic pathogenic variants occuring in distal exons tend to have a 'milder' clinical course.The pathogenic variant detected in Exon 13 was found in 2% of blood cells. NF2 comprehensive variant analysis (sequencing all exons & del/dup analysis) detects pathogenic varinats in >90% of non-founder NF2 patients & in 65-70% of sporadic patients (lower detection due to mosaicism frequently present in founder cases). The proband & his at risk children receieved genetic counseling.

Mild bilateral cystic kidney disease in NF2 moscaic case.