Results from a cross-sectional study out of Boston Children’s Hospital suggest that genetic risk factors for esotropia are also the risk factors for exotropia.
The study, involving 234 individuals, was conducted from 2005–2023. Individuals with constant or intermittent exotropia of any magnitude, or a history of surgery for exotropia, were recruited from paediatric ophthalmic practices.1
Genetic duplications associated with esotropia on chromosomes 2, 4, and 10 were also found to be present in 1.7%, 3.0%, and 6.0%, respectively, of individuals with exotropia. They reported that these proportions were similar to those found in individuals with esotropia, and higher than controls; “individuals with a duplication had a larger magnitude of exotropia, a higher frequency of constant (vs intermittent) deviation, and higher rates of strabismus surgery”.
Researchers said their findings support the possibility that esotropia and exotropia have shared genetic risk factors. “Whether esotropia or exotropia develops in the presence of these duplications may be influenced by other shared or independent genetic variants or by environmental factors.”
Reference
- Martinez Sanchez, M., Chan, W., MacKinnon, S.E., et al. Presence of copy number variants associated with esotropia in patients with exotropia. JAMA Ophthalmol. 2024;142(3):243–247. doi:10.1001/jamaophthalmol.2023.6782
