TY - JOUR T1 - Systemic sclerosis in a patient with muscle dystrophy JF - BMJ Case Reports JO - BMJ Case Reports DO - 10.1136/bcr-2022-250389 VL - 15 IS - 9 SP - e250389 AU - Sara Moutinho-Pereira AU - Eurico Morais-de-Sá AU - Helena Greenfield AU - P Ricardo Pereira Y1 - 2022/09/01 UR - http://casereports.bmj.com/content/15/9/e250389.abstract N2 - Systemic sclerosis is an autoimmune disease that can result in lung fibrosis, and is strongly associated with the presence of serum anti-topoisomerase-I autoantibodies. A young man with genetic muscular dystrophy caused by titin-cap/telethonin (TCAP) gene mutation, developed a severe restrictive lung disease due to a fibrosing interstitial pneumonia secondary to systemic sclerosis with positive anti-topoisomerase-I antibodies. Using amino acid sequence alignment and protein structure modelling, we found that mutant telethonin exposes an amino acid sequence with significant homology to an immunodominant site of topoisomerase-I. Abnormal telethonin results in a loss of integrity of the sarcomere structure, which might result in rhabdomyolysis and abnormal protein exposure to the immune system. Our preliminary analysis suggests a possible role for mutant sarcomere protein telethonin as an immunogenic target recognised by anti-topoisomerase-I antibodies, which could explain the development of systemic sclerosis in this particular patient. ER -