[Clinical and molecular genetic findings in isolated sporadic Duane syndrome]

Duane retraction syndrome (DURS) accounts for 1 - 4 % of all cases of strabismus. Approximately 90 % of the cases are sporadic with a preponderance for females and the left eye. Many associated ocular and systemic findings have been described. Recently, mutations of SALL4 have been found in patients with autosomal-dominantly inherited Okihiro syndrome (DURS associated with forearm malformations). The aim of this study was the clinical examination of patients with isolated sporadic DURS and the molecular genetic analysis of SALL4 in these patients.

Twenty-five patients with non-familial DURS (aged 1 - 75 years, 16 female, 9male) were examined clinically and were interviewed concerning associated pathologies. DNA was prepared from peripheral lymphocytes, and the complete coding region of SALL4 was sequenced.

In 18 patients DURS affected the left eye, in four the right eye, and was bilateral in three patients. One patient had fused vertebrae, one had a cone-rod-dystrophy. No hearing impairments or malformation of the upper limbs were observed. No mutation in the coding region of SALL4 could be detected.

Associated conditions in DURS patients most commonly involve the ear, the spinal column, the kidneys and the heart and the upper limbs. No mutations in SALL4 could be detected in patients with isolated sporadic DURS as opposed to findings in familial Okihiro syndrome. However, Okihiro syndrome shows marked intra- and interfamilial variability, suggesting that in rare cases of isolated DURS a causative SALL4 mutation may be found.