ClinVar

Scaglia et al. (2003) identified a 5843A-G transition in the MTTY gene in a girl with onset of steroid-resistant nephrotic syndrome caused by focal segmental glomerulosclerosis at age 2 years, and onset of dilated cardiomyopathy at age 7 years. The mutation occurred in a highly conserved region of the gene and was determined to be homoplasmic in the patient's skeletal muscle, blood, and renal tissue. Skeletal muscle biopsy showed a combined respiratory chain defect and a partial deficiency of coenzyme Q10. The patient's mother, who had a history of migraine headaches, was also homoplasmic for the 5843A-G mutation. Scaglia et al. (2003) concluded that other epigenetic factors must be involved to explain the clinical variability between the patient and her mother.