Duane syndrome
Duane syndrome, also known as Duane retraction syndrome, is a rare congenital disease characterized by non-progressive strabismus. It is caused by a variable degree of abnormal development of one or both 6th cranial nerves (CN VI).
Epidemiology
It presents during childhood and it accounts for less than 5% of cases of strabismus . Three subtypes of Duane syndrome are described:
- DRS type I: most common
- DRS type II
- DRS type III
Clinical presentation
The most common clinical presentation is strabismus because of hypoplasia/atrophy of the lateral rectus muscle. Other possible clinical presentation include amblyopia and blepharostenosis.
The majority of cases are unilateral, but it can be bilateral in up to 20% of patients.
Radiographic features
MRI
MRI findings consist of the following :
- hypoplasia/atrophy of the lateral rectus muscle
- the degree of atrophy is variable as the lateral rectus muscle may be reinnervated by aberrant branches from the 3cranial nerve (CN III)
- hypoplasia or absence of CN VI
Hypoplasia of other extra-ocular muscles have been described, depending on the subtype of the disease, especially the superior oblique muscle (DRS type I and II) .
See also
Siehe auch:
