Pediatric Radiology

, Volume 40, Issue 9, pp 1581–1581

Juvenile nephronophthisis on MRI—a potential case of Joubert syndrome?

Letter to the Editor

DOI: 10.1007/s00247-010-1707-6

Cite this article as:
Simms, R.J. & Sayer, J.A. Pediatr Radiol (2010) 40: 1581. doi:10.1007/s00247-010-1707-6


We read with interest the case presentation of “End-stage juvenile nephronophthisis on MRI” [1]. We are particularly curious about the child’s clinical presentation with an “abnormal gait” [1].

Nephronophthisis accounts for 6.5% of the children requiring renal replacement therapy in the United Kingdom and may be underdiagnosed [2]. As the authors acknowledge, an important feature of nephronophthisis is the association with extra-renal manifestations that can occur in up to 10% [3]. In their discussion, the authors mention Joubert syndrome, which is characterized by a mid-hindbrain malformation, cerebellar vermis hypoplasia and the diagnostic “molar tooth sign” on cerebral MRI [4]. We wonder whether the “abnormal gait” described in this child could be explained by Joubert syndrome and perhaps imaging with a brain MRI would be helpful?

The MRI of the kidneys clearly demonstrates the corticomedullary cysts characteristic of nephronophthisis/medullary cystic kidney disease [1]. Diagnosis should be confirmed by molecular genetic analysis. In isolated nephronophthisis, mutations in NPHP1 account for 20–25% of cases and can be screened for by polymerase chain reaction (see for a list of laboratories) [5]. Additionally, retinal screening for retinal dystrophy is indicated in all cases of suspected nephronophthisis.

Since nephronophthisis is an autosomal-recessive condition, with little genotype-phenotype correlation, the importance of a family history and reviewing other potentially at-risk relatives should be emphasised.

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Institute of Human Genetics—Nephrology, International Centre for LifeNewcastle UniversityNewcastle upon TyneUK