FXR1 and mucopolysaccharidosis type 3C: They revealed that increased levels of the GAS5 lncRNA correlate with the up-regulation of the HNRNPC gene in MPS IIIC, the down-regulation of the FXR1 gene in MPS IIIC, and the down-regulation of the MATR3 gene in MPS IIIB (Figure 3A).