Editorial commentary on "Gait phenotype in Batten disease: A marker of disease progression".

Batten disease, also known as neuronal ceroid lipofuscinosis, refers to a diverse group of 13 hereditary inborn errors of metabolism resulting in the abnormal accumulation of autofluorescent storage material in lysosomes leading to neurodegeneration, typically with associated intractable epilepsy, behavioral dysregulation, cognitive, motor, language and visual decline, as well as a shortened life expectancy [1]. Assessment of disease progression within this population is fraught with difficulty because individuals may have limited attention or cooperation affecting compliance with requested tasks, or have visual impairment reducing options for methods of assessment. Further, language and cognitive assessments have been designed to assess typically developing individuals based on specific age limits, which then fail to capture low developmental functioning once the mental age of the individual drops below the basal age of the assessment tool. Yet, metrics to measure disease progression are essential to inform therapeutic decision-making, prognostication, and clinical trial outcomes.