Abstract
Objective: To analyze the clinical manifestations of a patient with
Okihiro syndrome/Duane-radial ray syndrome (DRRS) and his family and to
carry out genetic testing in order to specify the biological
pathogenesis. Methods: Clinical data of the patient and his family were
collected. Genomic DNA in the peripheral blood of the proband and his
family members was extracted. whole exome were sequenced by
high-throughput sequencing, and the mutation sites of the proband and
his parents were validated by Sanger sequencing. Results: The patient
was diagnosed with Okihiro syndrome that characterized by abnormalities
of bones in the arms and hands (radial ray malformations, absence of
thumbs) and sensorineural hearing loss. A pathogenic heterozygous
c.3060delG variant has been identified in exon 4 of the SALL4 gene in
the proband by whole exome sequencing (WES), which is a frameshift
mutation that changed the amino acid sequence of the SALL4 protein from
1053 to 1076 . This variant resulted in a longer SALL4 protein. The
variant was a de novo mutation, as the parents of the proband showed no
variation at this site. This variant has not been included in the
database and has not been reported in the literature. Conclusion: The de
novo heterozygous c.3060delG variant was the molecular pathological
cause of Okihiro syndrome in this study. The variant detected in this
case expanded the database of SALL4 variants.