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Abstract

Clinical and Genetic Findings in Mexican Patients with Duane Anomaly and Radial Ray Malformations/Okihiro Syndrome

VOLUME 68 - NUMBER 5 / September - October (Original articles)

Óscar F. Chacón-Camacho, Genetics Department Research Unit, Instituto de Oftalmología Conde de Valenciana, Mexico City, Mexico
Jesús Cabral-Macías, Genetics Department Research Unit, Instituto de Oftalmología Conde de Valenciana, Mexico City, Mexico
Raúl Ayala-Ramírez, Genetics Department Research Unit, Instituto de Oftalmología Conde de Valenciana, Mexico City, Mexico
Jazmin Arteaga-Vázquez, Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
Yevgeniya Svyryd, Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
Karla Helmes, Centro de Rehabilitación Infantil Teletón, Oaxaca, Oax, Mexico
Nohemí Pérez-Hernández, Centro de Rehabilitación Infantil Teletón, Oaxaca, Oax, Mexico
Osvaldo M. Mutchinick, Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
Juan C. Zenteno, Rare Disease Diagnostic Unit, Faculty of Medicine, Universidad Autónoma de México (UNAM), Mexico City, Mexico; Department of Biochemistry, Faculty of Medicine, UNAM, Mexico City, Mexico

Background: Okihiro syndrome is an autosomal-dominant condition characterized by radial ray malformations associated with Duane anomaly and other clinical characteristics. SALL4 mutations have been identified in 80-90% of patients with Duane-Radial ray defects/Okihiro syndrome. We report the clinical findings and results of SALL4 sequencing from a group of Mexican patients with this disorder. Objective: Clinical description and identification of SALL4 mutations in Mexican subjects with radial defects and Duane anomaly. Materials and methods: Five unrelated index cases were studied. Complete ophthalmologic and general physical examination was performed in all patients. Polymerase chain reaction amplification and automated nucleotide sequencing of coding exons and intron-exon junctions of SALL4 gene were carried out in genomic DNA. Results: A novel heterozygous deletion was identified in one patient. Intragenic heterozygous single nucleotide polymorphisms on SALL4 gene ruled out deletions of some exons in other affected patients in whom non-pathogenic variants were identified by Sanger sequencing. Likewise, multiplex ligation-dependent probe amplification analysis ruled out large deletions in this gene. Conclusion: We observed a low frequency of SALL4 mutations in Mexican patients with clinical criteria of Okihiro syndrome.

Keywords: Duane anomaly. DRS. Okihiro syndrome. Radial ray defects. SALL4 disorder. SALL4 gene. Strabismus.

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