ABCG2 and juvenile Huntington disease: Emerging evidence suggests that dysfunction of ABC transporters contributes to the development and progression of various neurological and neurodegenerative diseases, including Alzheimer’s disease (AD) [11,12,13,14], Parkinson’s disease (PD) [15,16,17,18,19], Huntington’s disease (HD) [20,21], and drug-resistant epilepsy [22,23,24,25,26].