Role of Abelson Helper Integration Site 1, Nebulin, and Paired Box 3 Genes in the Development of Nonsyndromic Strabismus in a Series of Iranian Families: Sequence Analysis and Systematic Review of the Genetics of Nonsyndromic Strabismus.

Purpose: To look for causative genetic mutations in a series of Iranian families with strabismus. In addition, we systematically reviewed all the published articles regarding the role of genetic variations in primary and nonsyndromic comitant strabismus.

Methods: Four families with a history of multiple cases of primary and nonsyndromic comitant strabismus were enrolled in this study. Polymerase chain reaction and Sanger sequencing of exons 23, 11, and 3 of the Abelson helper integration site 1 (AHI1), nebulin (NEB), and paired box 3 (PAX3) genes were performed, respectively. One offspring of a consanguineous marriage underwent whole-exome sequencing (WES) to look for possible causative variants. To conduct a systematic review, we thoroughly searched PubMed, Scopus, and ISI Web of Knowledge extracting relevant publications, released by April 2021.

Results: We examined four Iranian strabismus pedigrees with multiple affected offspring in different generations. Among these 17 participants, 10 family members had strabismus and 7 were healthy. Sanger sequencing did not reveal a causative mutation. Therefore, to further investigate, one affected offspring was chosen for WES. The WES study demonstrated two possible variants in MYO5B and DHODH genes. These genetic variants showed high allele frequency in our population and are thought to be polymorphisms in our series of Iranian families.

Conclusions: We demonstrated that mutations in AHI1, NEB, and PAX3 genes were not common in a series of Iranian patients with familial strabismus. Moreover, by performing WES, we revealed that two variants of uncertain significance as possible causative variants for strabismus are not related to this disease in our population.