Chromosome: 20q13.2
Gene: SALL4 (Sal-like protein 4)
Inheritance: autosomal dominant
Key features:
(1) Duane anomaly, which may be unilateral or bilateral
(2) radial ray anomalies
Okihiro’s syndrome involves the key features plus sensorineural hearing loss.
Duane anomaly consists of:
(1) unilateral or bilateral limitation in eye abduction secondary to abnormal innervation of the lateral rectus muscle
(2) retraction of the globe
(3) narrowing of the palpebral fissue on adduction
(4) absence of cranial nerve VI (abducens nucleus and nerve) with a branch of cranial nerve III (oculomotor nerve) innervating the lateral rectus muscle
Radial ray anomaly may involve one or more of the following:
(1) thenar hypoplasia
(2) hypoplasia or aplasia of the thumbs
(3) hypoplasia or aplasia of the radii
(4) shortening and radial deviation of the forearm
(5) triphalangeal thumbs
(6) preaxial polydactyly with duplicaton of the thumb
The patient may also have other features seen in SALL4-related disorders (see below).
