Barth syndrome (BTHS) is a rare X-linked mitochondrial disorder caused by tafazzin mutations that impair cardiolipin remodeling, leading to mitochondrial dysfunction and symptoms such as cardiomyopathy, myopathy, and neutropenia. On September 19, 2025, the U.S. Food and Drug Administration (FDA) granted accelerated approval to elamipretide, the first therapy directly targeting the mitochondrial etiology of BTHS. Elamipretide binds to cardiolipin on the inner mitochondrial membrane, stabilizing respiratory chain supercomplexes, enhancing electron transport efficiency, and reducing reactive oxygen species production. In a randomized, double-blind, placebo-controlled, crossover trial, elamipretide resulted in no significant improvement in the 6-minute walk test or fatigue scores; however, sustained benefits were observed during a 168-week open-label extension. The most common adverse events were mild injection-site reactions. As a condition of accelerated approval, a confirmatory trial is required. Elamipretide represents a promising therapy addressing an unmet medical need in BTHS and provides a foundation for future mitochondria-targeted treatments.

The World Health Organization (WHO) has approved a new diagnostic code, "5B72 Undernutrition in Adults", in the 11th Revision of the International Classification of Diseases (ICD-11). Prior to this update, undernutrition in adults was represented only by the code "5B54 Underweight in Adults". However, the increasing diversity of causes of undernutrition in adults and the accompanying rise in associated diseases have been recognized as global health challenges in recent years. The approval of the "5B72 Undernutrition in Adults" category signifies its formal recognition as a distinct disease entity and is expected to improve data collection and research, enhance clinical diagnosis and interventions, and support policy development and nutritional education.