Kearns-Sayre syndrome
| Kearns-Sayre syndrome | |
|---|---|
| Synonyms | oculocraniosomatic disorder, oculocraniosomatic neuromuscular disorder with ragged red fibers |
| Classification and external resources | |
| Specialty | ophthalmology |
| ICD-10 | H49.8 |
| ICD-9-CM | 277.87 |
| OMIM | 530000 |
| DiseasesDB | 7137 |
| eMedicine | article/950897 |
| MeSH | D007625 |
| GeneReviews | |
Kearns–Sayre syndrome (KSS) is a with a typical onset before 20 years of age. KSS is a more severe syndromic variant of chronic progressive external ophthalmoplegia (abbreviated CPEO), a syndrome that is characterized by isolated involvement of the muscles controlling movement of the eyelid (levator palpebrae, orbicularis oculi) and eye (extra-ocular muscles). This results in ptosis and ophthalmoplegia respectively. KSS involves a combination of the already described CPEO as well as pigmentary retinopathy in both eyes and cardiac conduction abnormalities. Other symptoms may include cerebellar ataxia, proximal muscle weakness, deafness, diabetes mellitus, growth hormone deficiency, hypoparathyroidism, and other endocrinopathies. In both of these diseases, muscle involvement may begin unilaterally but always develops into a bilateral deficit, and the course is progressive. This discussion is limited specifically to the more severe and systemically involved variant.
Individuals with KSS present initially in a similar way to those with typical CPEO. Onset is in the first and second decades of life.
The first symptom of this disease is a unilateral ptosis, or difficulty opening the eyelids, that gradually progresses to a bilateral ptosis. As the ptosis worsens, the individual commonly extends their neck, elevating their chin in an attempt to prevent the eyelids from occluding the visual axis. Along with the insidious development of ptosis, eye movements eventually become limited causing a person to rely more on turning the head side to side or up and down to view objects in the peripheral visual field.
KSS results in a pigmentation of the retina, primarily in the posterior fundus. The appearance is described as a "salt-and-pepper" appearance. There is diffuse depigmentation of the retinal pigment epithelium with the greatest effect occurring at the macula. This is in contrast to retinitis pigmentosa where the pigmentation is peripheral. The appearance of the retina in KSS is similar to that seen in myotonic dystrophy type 1 (abbreviated DM1). Modest night-blindness can be seen in patients with KSS. Visual acuity loss is usually mild and only occurs in 40–50% of patients.
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