Stroke-like lesions (SLL) are common radiological findings in patients with mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (SLE; MELAS) harboring the m.3243A>G MTTL1 mutation.
The m.3243A>G mutation in the mitochondrial gene MT-TL1 leads to a wide clinical spectrum ranging from asymptomatic carriers to MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) at the severe end.
The nucleotide change A to G at position m.3243 in the mitochondrial tRNA leucine (UUR) gene (MT-TL1) is the most common point mutation reported in association with the Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes (MELAS) syndrome.
This report highlights the need to screen various tissues to achieve an accurate mitochondrial genetic diagnosis and suggests the likelihood of myositis arising secondary to the MELASMT-TL1 m.3243A>G mutation.
To investigate this point, we compared the mutant levels in 51 first polar bodies (PBs) and their counterpart (oocytes, blastomeres, or whole embryos), at risk of having (1) the "MELAS" m.3243A>G mutation in MT-TL1 (n = 30), (2) the "MERRF" m.8344A>G mutation in MT-TK (n = 15), and (3) the m.9185T>G mutation located in MT-ATP6 (n = 6).
We tracked the segregation of the m.3243A>G mutation (MT-TL1 gene) responsible for the MELAS syndrome in the developing embryo/fetus, using tissues and cells from eight carrier females, their 38 embryos and 12 fetuses.