Kearns-Sayre syndrome

Kearns-Sayre syndrome (KSS), also known as oculocraniosomatic disorder, is a rare multisystem mitochondrial disorder.

Epidemiology

Symptoms develop in childhood or adolescence, usually before 20 years of age ^3,6.

Clinical presentation

The core clinical manifestations are chronic progressive external ophthalmoplegia (CPEO) and retinal pigmentation ^1,6. Additionally, patients with Kearns-Sayre syndrome will have one or more of ^4,6:

• cardiac conduction defects

• ataxia

• raised CSF protein

Pathology

The disease is characterized by the ragged-red appearance of muscle fibers, and the presence of mitochondrial DNA (mtDNA) with large deletions in affected tissues (and usually not in the blood) ⁶. In the brain, it tends to affect peripheral white matter early and preferential involvement of the globi pallidi and thalami.

Genetics

It is sporadic in a majority of cases ⁶.

Radiographic features

CT

CT scan of the brain shows basal ganglia siderocalcific deposits and subcortical calcifications (with or without basal ganglia deposits), and diffuse supratentorial and infratentorial atrophy.

MRI 

Cerebral, cerebellar and brainstem atrophy are mainstay features of the disease ².

Signal characteristics include:

• T2: subcortical prolongation with subcortical calcifications, with or without bilateral basal ganglia siderocalcific deposits

History and etymology

It was initially described by Thomas P Kearns and George Pomeroy Sayre in 1958 ⁵.

Differential diagnosis

Imaging differential considerations include

• other mitochondrial disorders, e.g. Leigh syndrome

• chronic progressive external ophthalmoplegia (CPEO): Kearns-Sayre syndrome is often considered a severe syndromic variant of CPEO