Kearns-Sayre Syndrome


KEY FACTS

Terminology

  • Clinical phenotypes associated with single large-scale mtDNA deletions (SLSMDs)

    • Kearns-Sayre syndrome (KSS)

    • Chronic progressive external ophthalmoplegia

    • Pearson syndrome

      • Multisystem disorder characterized by bone marrow failure, pancreatic insufficiency

      • Children who survive develop KSS later in life

  • SLSMDs often exhibit overlapping disease spectrum

    • Most common non-CNS disease; anemia, renal impairment, endocrine disturbance

Imaging

  • Can be normal (especially early in disease)

  • Diffuse symmetric Ca++ in basal ganglia on NECT

  • ↑ T2 signal in hemispheric subcortical WM, U fibers, corpus callosum, globi pallidi, substantia nigra, posterior brainstem

    • Early sparing of periventricular WM

    • Occasional radial stripes in hyperintense WM

  • Posterior fossa lesions

    • Dorsal brainstem, bilateral brachium pontis; cerebellar WM

Pathology

  • Polygenetic: Caused by various mtDNA rearrangements

  • Status spongiosus, spongy myelinopathy

  • Cerebellar atrophy

  • Ragged-red fibers on muscle biopsy

Clinical Issues

  • Common symptoms: Progressive external ophthalmoplegia, ataxia, retinitis pigmentosa, sensorineural hearing loss

  • Additional symptoms: Short stature, proximal muscle weakness, diabetes

    • Cardiac abnormalities 1 of most feared complications

  • Age of onset usually before 20 years

Clinical photograph of a patient with chronic progressive external ophthalmoplegia (CPEO). He had weakness of eye closure and limitation of gaze in all directions.

Axial T2WI MR in a teenager with symptomatic Kearns-Sayre syndrome demonstrates abnormal increased signal intensity bilaterally in the brachium pontis
, dorsal pons
, and cerebellum
. Widening of the interfoliate sulci results from mild cerebellar atrophy.

Axial T2WI MR in the same teenager demonstrates foci of abnormal signal bilaterally within the globi pallidi
and the corticospinal tracts
. Note the subtle loss of myelin arborization into the subcortical U fibers
.

Coronal FLAIR MR in the same patient shows abnormal hyperintense signal in corticospinal tracts
, subcortical U fibers
, and thalami
.

TERMINOLOGY

Definitions

  • Clinical phenotypes associated with single large-scale mtDNA deletions (SLSMDs)

    • Progressive external ophthalmoplegia (PEO)

    • Kearns-Sayre syndrome (KSS)

    • Pearson syndrome

      • Multisystem disorder characterized by bone marrow failure, pancreatic insufficiency

      • Children who survive develop KSS later in life

  • Overlapping spectrum of disease

    • Multisystem disease with anemia, renal impairment, endocrine disturbance most frequent extraneurological features

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