By analyzing the expression of Glucose Transporter 1 (GLUT1) and Glucose Transporter 3 (GLUT3) proteins in PHD, JOHD, and adult-onset HD patients compared to controls, they observed a significant reduction in GLUT1 and GLUT3 levels in the frontal cortex and fibroblasts of PHD patients with highly expanded mutations. This evidence concerns the gene SLC2A3 and Adult onset.