Mitochondrial Retinopathy Due to MT-TL1 Mutation: The Role of Heteroplasmy. A Case Report

Summary

Objective: To report a case of mitochondrial retinopathy, highlighting its clinical and imaging findings, the importance of genetic confirmation, and the possible implications of heteroplasmy in this disease.

Material and Methods: Case report of a mitochondrial retinopathy secondary to m.3243A>G mutation in the MT-TL1 gene.

Results: A 32-year-old woman presented with bilateral vision loss, photophobia, and sensorineural hearing loss for more than 3 years. Best corrected visual acuity (BCVA) was 20/60 in the right eye (OD) and 20/25 in the left eye (OS). Fundus examination revealed multiple macular subretinal yellow-white deposits and central chorioretinal atrophy, without edema, hemorrhage, or subretinal fluid in the RE, and juxtafoveal atrophy with retinal pigment epithelium (RPE) metaplasia in the OS. Multimodal imaging raised suspicion of retinal dystrophy, and genetic testing confirmed a mitochondrial retinopathy secondary to the m.3243A>G mutation in the MT-TL1 gene.

Conclusions: Bilateral and symmetric RPE atrophic changes in young individuals, especially when associated with systemic symptoms, should prompt a comprehensive evaluation, including multimodal imaging and genetic testing. Identifying causative mutations and understanding the dynamics of mitochondrial DNA in the pathogenesis of these diseases is crucial for improving diagnosis and suggesting potential therapeutic strategies, including gene therapy.

Keywords:

Heteroplasmy – mitochondrial disease – MT-TL1 gene – m.3243A>G mutation