Description

Okihiro syndrome is a syndrome of multiple congenital anomalies and is characterized by ocular manifestations (uni- or bilateral Duane anomaly (95% of cases), congenital optic nerve hypoplasia or optic disc coloboma), bilateral deafness and radial ray malformation that can include thenar hypoplasia and/or hypoplasia or aplasia of the thumbs; hypoplasia or aplasia of the radii; shortening and radial deviation of the forearms; triphalangeal thumbs; and duplication of the thumb (preaxial polydactyly).The phenotype overlaps with other SALL4>/i> related disorders including acro-renal-ocular syndrome and Holt-Oram syndrome (see these terms). Transmission is autosomal dominant. Genetic cause for individuals with DRRS (Duane radial ray syndrome; Okihiro Syndrome), that is Duane syndrome (unilateral or bilateral) with a skeletal change of radial dysplasia (unilateral or bilateral) ranging from most commonly thumb hypoplasia to most severely a phocomelic limb (similar to that seen in thalidomide cases), has been found. Other features include deafness, renal and ocular manifestations. Inheritance is autosomal dominant. Truncating mutations and SALL4 gene deletions have been identified in DRRS families, there is haploinsufficiency (the level of the protein is not sufficient for normal functioning). No SALL4 gene mutations were found in 25 sporadic cases of isolated DS.

External Information

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