Segmental and Focal Glomerulosclerosis Secondary to MELAS Syndrome and Long-Term Outcomes After Kidney Transplant: Case Report and Literature Review.

Mitochondrial disease is a heterogeneous group of disorders with variable clinical and laboratory manifestations. The most common mitochondrial DNA defect is the transition of adenine to guanine at position 3243 (m.3243A≥G) on the MT-TL1 gene, causing a systemic syndrome known as MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes). The kidney is particularly susceptible to mitochondrial diseases due to its high oxygen consumption and abundance of mitochondria. Tubular cells and podocytes can be affected by these diseases, resulting in diverse clinical and laboratory manifestations. We reported a case of a 31-year-old female patient with bilateral sensorineural deafness diagnosed with the m.3243A≥G sequence variant in adulthood. At the time of diagnosis, she had end-stage renal disease secondary to focal segmental glomerulosclerosis. Her sister was diagnosed with MELAS syndrome, and mitochondrial disease was investigated. After 27 months on dialysis, our patient received a kidney transplant from a deceased donor and presented nonnephrotic range proteinuria within the first month after transplant. Despite developing de novo donor-specific antibodies after COVID-19, the function of the transplanted kidney remained stable. With adjustment to the maintenance immunosuppression therapy, there was a gradual decrease in the mean fluorescence intensity of de novo donor-specific antibodies. The graft function and proteinuria remained stable throughout a 5-year follow-up, which is similar to a follow-up reported in the literature. The kidney is especially vulnerable to mitochondrial diseases. In this report, posttransplant outcomes were satisfactory in a 5-year follow-up, similar to those reported by other authors.