DUANE RADIAL RAY SYNDROME (OKIHIRO SYNDROME)

SALL4 GENE ANALYSIS IN DUANE RADIAL RAY SYNDROME

Duane Radial Ray syndrome (DRRS) (Also known as Okihiro syndrome, Duane anomaly with radial ray abnormalities and deafness, DR syndrome and Acro-reno-ocular syndrome) is an autosomal dominant condition characterised by unilateral or bilateral radial sided hand malformations and Duane retraction syndrome congenital eye movement disorder.

DRRS is caused by disease-causing variants in the SALL4 gene. Sequencing of the SALL4 gene identifies a variant in 80% of individuals with DRRS (Al-Baradie et al 2002 Am J Hum Gen 71(5), 1195-9, Kohlhase et al 2002 Hum Mol Genet 11, 2979-87, Borozdin et al 2004 J Med Genet 41:e113, Kohlhase et al 2005 Hum Mutat 26,176–83). Whole and partial SALL4 gene deletions have been reported in DRRS including single exon deletions (exon 1 and 4), deletions involving exons 1, 2 and 3, and whole gene deletions (Borozdin et al 2004 J Med Genet 41:e113). Sequencing and dosage analysis of the SALL4 gene identified a variant in 90-95% of cases (Kohlhase et al 2005 Hum Mutat 26,176–83). Penetrance is incomplete, estimated at 95%, as non-manifesting variant carriers have been described (Kohlhase et al 2002 Hum Mol Genet 11, 2979-87).

The laboratory participates in the European Molecular Genetics Quality Network (EMQN) sequencing scheme.