Pediatric Radiology

, Volume 40, Issue 9, pp 1581–1581

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

Letter to the Editor
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Sir,

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 http://www.orpha.net 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.

References

  1. 1.
    Stafrace S, Khan J (2010) End-stage juvenile nephronophthisis on MRI. Pediatr Radiol Feb 25 [Epub ahead of print]Google Scholar
  2. 2.
    Lewis M, Shaw J, Reid C et al (2007) Demography and management of childhood established renal failure in the UK (chapter 13). Nephrol Dial Transplant 22:vii165–175Google Scholar
  3. 3.
    Simms RJ, Eley L, Sayer JA (2009) Nephronophthisis. Eur J Hum Genet 17:406–416CrossRefPubMedGoogle Scholar
  4. 4.
    Valente EM, Salpietro DC, Brancati F et al (2003) Description, nomenclature, and mapping of a novel cerebello-renal syndrome with the molar tooth malformation. Am J Hum Genet 73:663–670CrossRefPubMedGoogle Scholar
  5. 5.
    Hildebrandt F, Zhou W (2007) Nephronophthisis-associated ciliopathies. J Am Soc Nephrol 18:1855–1871CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

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

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