MITOCHONDRIAL DISEASES & METABOLIC MYOPATHIES: P.313 Design of a phase 3 prospective clinical study for the treatment of thymidine kinase 2 deficiency (TK2d)

Abstract

TK2d is an ultra-rare and often lethal disorder, caused by autosomal recessive mutations in TK2 resulting in mitochondrial DNA depletion and deletion. TK2d presents as progressive proximal muscle weakness in all patients; however, there is clinical heterogeneity, with a spectrum of severity and functional impairment. TK2d-reported categories were originally based on age of onset: infantile, juvenile/childhood, and late/adult-onset. Late-onset TK2d represents the smallest number of reported cases, with less available data than for the younger patients.