Seventeen-year follow-up of mitochondrial myopathy and ataxia in a Chinese family: case reports and literature review.
Case Report
To investigate the retinal phenotype and genetic features of a Chinese family with a diagnosis of mitochondrial myopathy and ataxia (MMYAT)./r/nWe conducted a 17-year follow-up of two sisters from a Chinese family and reviewed their medical and family histories. The retinal phenotype was assessed using a multi-modal imaging technique, which includes ultra-widefield (UWF) scanning laser ophthalmoscope (SLO), UWF fundus autofluorescence (FAF), and optical coherence tomography (OCT). Whole exome sequencing (WES) was performed to detect pathogenic variants. Sanger sequencing validation and segregation analysis were further performed for the confirmation of genetic results. A literature review was conducted, analysing the data from 11 published articles encompassing 33 confirmed cases of MMYAT up to 2025./r/nOphthalmic multimodal imaging examination revealed typical characteristics of retinal dystrophy in both patients, including binocular widespread salt-and-pepper pigmentation, macular atrophy, a mottled pattern of hypoautofluorescence, and degeneration of the ellipsoid zone. A comprehensive review of the patients’ histories identified muscle weakness, ataxia, cerebellar atrophy, mild cognitive impairment, and developmental delay. Two compound heterozygous variants of the mitochondrial distribution and morphology regulator 1 (MSTO1) gene (NM_018116.3), c.971C > T (p.T324I) and c.1108G > A (p.A370P), were detected using WES. A comprehensive literature review was also conducted to gain an overview of the various symptoms associated with MMYAT./r/nOur study provides a comprehensive ophthalmic characterization of MMYAT, indicating that retinal dystrophy is a key characteristic of this disease. Multimodal imaging of the retina is beneficial for diagnosing MMYAT-associated retinal dystrophy. Increased awareness and comprehensive ophthalmic examination are crucial for obtaining an early and accurate diagnosis.
