A case of mitochondrial diabetes mellitus complicated with hypopituitarism and literature review / 中华内分泌代谢杂志

The clinical data of a patient with mitochondrial diabetes mellitus complicated with hypopituitarism were analyzed, the patient′s mitochondrial gene was detected by microarray capture high-throughput sequencing, and the related domestic and foreign literature was reviewed and analyzed. The results showed that the patient had m. 3243 A>G variant on MT-TL1 gene and the clinical features were consistent with mitochondrial diabetes mellitus and hypopituitarism.

MELAS syndrome caused by A3252G mutation in MT-TL1 gene: One case report and literature review / 中华内分泌代谢杂志

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes(MELAS) is one of the most common inherited mitochondrial diseases. This paper reports a rare mutation associated with MELAS syndrome, the m. 3252 A>G mutation in the MT-TL1 gene encoding the mitochondrial tRNALeu(UUR). The 6-year-old girl suffered from recurrent convulsion and lactic acidemia. The mtDNA sequencing detected a variant m. 3252A>G(MT-TL1 gene) in the proband and her maternal relatives. The heteroplasmic levels in peripheral blood and urine sediment were 66.53% and 97.42%, respectively, which were obviously higher than those of her maternal relatives. Together with 3 previously reported cases, the variant m. 3252A>G could be classified pathogenic. All the reported pathogenic variants in MT-TL1 gene were reviewed to explore the genotype-phenotype correlations of pathogenic variants in MT-TL1 gene.

A Case of Atypical Leber Hereditary Optic Neuropathy Associated with MT-TL1 Gene Mutation Misdiagnosed with Glaucoma

PURPOSE: Leber hereditary optic neuropathy (LHON) is one of the most common hereditary optic neuropathies caused by mutations of mitochondrial DNA. Three common mitochondrial mutations causing LHON are m.3460, m.11778, and m.14484. We report a rare mutation of the mitochondrial tRNA (Leu [UUR]) gene (MT-TL1) (m.3268 A > G) in a patient with bilateral optic atrophy. CASE SUMMARY: A 59-year-old female diagnosed with glaucoma 3 years earlier at a community eye clinic presented to our neuro-ophthalmology clinic. On examination, her best corrected visual acuity was 0.4 in the right eye and 0.7 in the left eye, and optic atrophy was noticed in both eyes. Optical coherence tomography revealed retinal nerve fiber layer (RNFL) thinning in both eyes; average RNFL thickness was 52 µm in the right eye and 44 µm in the left eye, but the papillomacular bundle was relatively preserved in both eyes. Goldmann perimetry demonstrated peripheral visual field defects, mostly involving superotemporal visual field in both eyes. Mitochondrial DNA mutation test showed an unusual mutation in MT-TL1 gene seemingly related to this optic neuropathy. CONCLUSIONS: We found a rare mutation (m.3268 A > G) of the mitochondrial DNA in a patient having bilateral optic atrophy, which led to the diagnosis of LHON. There have been previous reports about mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) and infantile myopathy caused by MT-TL1 mutation, but this is the first case of LHON associated with the same mutation. In this case of LHON associated with MT-TL1 mutation, atypical clinical features were observed with a relatively mild phenotype and peripheral visual field defects.