Unusual white matter involvement in EAST syndrome associated with novel KCNJ10 mutations

  • Mariasavina Severino
  • Susanna Lualdi
  • Chiara Fiorillo
  • Pasquale Striano
  • Teresa De Toni
  • Silvio Peluso
  • Giuseppe De Michele
  • Andrea Rossi
  • Mirella Filocamo
  • Claudio Bruno
Original Communication

Abstract

Background

Epilepsy, ataxia, sensorineural deafness, and tubulopathy (EAST syndrome) is a rare channelopathy due to KCNJ10 mutations. So far, only mild cerebellar hypoplasia and/or dentate nuclei abnormalities have been reported as major neuroimaging findings in these patients.

Methods

We analyzed the clinical and brain MRI features of two unrelated patients (aged 27 and 23 years) with EAST syndrome carrying novel homozygous frameshift mutations (p.Asn232Glnfs*14and p.Gly275Valfs*7) in KCNJ10, detected by whole exome sequencing.

Results

Brain MRI examinations at 8 years in Patient 1 and at 13 years in Patient 2 revealed a peculiar brain and spinal cord involvement characterized by restricted diffusion of globi pallidi, thalami, brainstem, dentate nuclei, and cervical spinal cord in keeping with intramyelinic edema. The follow-up studies, performed, respectively, after 19 and 10 years, showed mild cerebellar atrophy and slight progression of the brain and spinal cord T2 signal abnormalities with increase of the restricted diffusion in the affected regions.

Conclusion

The present cases harboring novel homozygous frameshift mutations in KCNJ10 expand the spectrum of brain abnormalities in EAST syndrome, including mild cerebellar atrophy and intramyelinic edema, resulting from abnormal function of the Kir4.1 inwardly rectifying potassium channel at the astrocyte endfeet, with disruption of water-ion homeostasis.

Keywords

Kir4.1 KCNJ10 EAST syndrome SeSAME syndrome Brain MRI Diffusion-weighted imaging Intramyelinic edema Astrocytopathy Channelopathy Whole exome sequencing Frameshift variants 

Notes

Acknowledgements

Patient samples were obtained from the “Cell Line and DNA Biobank from patients affected by Genetic Diseases” (Istituto Giannina Gaslini), member of Telethon Network of Genetic Biobanks (project no. GTB12001). This work was partially supported by unrestricted grants from “Cinque per mille e Ricerca Corrente, “Ministero della Salute” to MF and SL.

Author contributions

MS: conception and design of the work, analysis and interpretation of brain MRI data. Drafting of manuscript, tables and figures. SL: acquisition, analysis and interpretation of mutation analysis data. Drafting of manuscript, tables and figures. CF: conception and design of the work. Collection and interpretation of patient 1 clinical data. Drafting the manuscript and revising critically for important intellectual content. PS: Collection and interpretation of patient 1 clinical data. Drafting the manuscript and revising critically for important intellectual content. TT: Collection and interpretation of patient clinical data. SP: Collection and interpretation of patient 2 clinical and neuroimaging data. GM: Drafting the manuscript and revising critically for important intellectual content. AR: acquisition of brain MRI data. Drafting the manuscript and revising critically. MF: acquisition of genetic results. Drafting the manuscript and revising critically for important intellectual content. CB: Drafting the manuscript and revising critically.

Compliance with ethical standards

Conflicts of interest

On behalf of all authors, the corresponding author states that there is no conflict of interest.

Ethical statement

No ethic committee approval is required for this retrospective study report.

Supplementary material

415_2018_8826_MOESM1_ESM.tiff (117 kb)
Online Figure 1: Family pedigree of patients
415_2018_8826_MOESM2_ESM.tiff (4.6 mb)
Online Figure 2: Brain MRI and MR spectroscopy of Patient 1 at the age of 27 years (A-C) and of Patient 2 at the age of 23 years (D-F). Coronal (A, D) and sagittal (B, E) T2-weighted images reveal high signal in the upper cervical spinal cord (arrows). The brainstem is slightly smaller, and the corpus callosum is thin (thick arrows). Note reduction of the vermian volume (arrowheads). (C, E) Proton MR spectroscopy of the brainstem shows slightly reduced NAA in Patient 1 (empty arrow) and absence of lactate peaks in both patients
415_2018_8826_MOESM3_ESM.tiff (3.7 mb)
Online Figure 3: Brain MRI examinations performed at 8 years of age (A) and 28 years of age (B, C) in Patient 1. The first MRI reveals normal cerebellar volume (thick arrows, A), while the follow-up study demonstrates mild and slowly progressive cerebellar atrophy, more pronounced at the level of superior cerebellar hemispheres (thick arrows, B). Note the evolution of the T2-hyperintensity changes at the level of the globi pallidi (arrows) and thalami (arrowheads).
415_2018_8826_MOESM4_ESM.tiff (3.6 mb)
Online Figure 4: Brain MRI examinations performed at 13 years of age (A) and 23 years of age (B, C) in Patient 2. The first MRI reveals normal cerebellar volume (thick arrows, A), while the follow-up study demonstrates mild and slowly progressive cerebellar atrophy, more pronounced at the level of superior cerebellar hemispheres (thick arrows, B). Note the evolution of the T2-hyperintensity changes at the level of the midbrain (arrows) and globi pallidi (arrowheads).
415_2018_8826_MOESM5_ESM.docx (20 kb)
Supplementary material 5 (DOCX 20 kb)
415_2018_8826_MOESM6_ESM.docx (131 kb)
Supplementary material 6 (DOCX 130 kb)

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Neuroradiology UnitIstituto Giannina GasliniGenoaItaly
  2. 2.UOSD, Centro di Diagnostica Genetica e Biochimica delle Malattie MetabolicheIstituto Giannina GasliniGenoaItaly
  3. 3.Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child HealthUniversity of Genoa, Istituto Giannina GasliniGenoaItaly
  4. 4.Pediatric ClinicIstituto Giannina GasliniGenoaItaly
  5. 5.Department of Neurosciences and Reproductive and Odontostomatological SciencesFederico II UniversityNaplesItaly
  6. 6.Center of Translational and Experimental MyologyIstituto Giannina GasliniGenoaItaly

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