Kearns-Sayre syndrome

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

Clinical presentation

PatientThe patient often present with progressive external ophthalmoplegia ¹. Neurologic symptoms develop in childhood or adolescence, usually before 20 years of age ³.

Other features include:

• cardiac conduction defects ⁴
• retinal pigmentation
• ptosis

Pathology

The disease is characterised by the ragged-red appearance of muscle fibers, and the presence of mtDNA with large deletions in affected tissues. It tends to affect peripheral white matter early and preferential involvement of the globi pallidi and thalami.

Genetics

It is sporadic in a majoirtymajority of cases.

Radiographic features

CT brain

CT-scan 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 brain  

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): some consider KSS as a syndromic variant of CPEO