(A) SGSH enzyme activity in WT mice is higher in all bowel regions versus brain. (B) No significant difference in overall bowel length (pylorus to anus) between genotypes. (C–E) H&E-stained jejunal sections show normal bowel architecture with intact villi, crypts, and smooth muscle in both genotypes, with no significant difference when quantified. (F) HuC/D-immunostained myenteric plexus reveals well-preserved ganglion organization. (G) HuC/D⁺ neuron densities were statistically equivalent in duodenum and colon, with a small but significant reduction in ileum neuron density in Sgsh^–/– mice. (H) Ileum of Sgsh^–/– mice also shows significantly fewer S100B⁺ but not GFAP⁺ enteric glia. (I and J) Carmine red (n = 12 mice/group) and FITC–dextran assays (n = 13 mice/group) revealed similar whole bowel transit and segmental distribution. Scale bars: 200 μm (C, F, and H). Data are shown as mean ± SEM (B, D, E, and G–I), using unpaired 2-tailed t test. *P < 0.05, **P < 0.01.