Idiopathic normal pressure hydrocephalus (iNPH) is a common neurological disorder that is characterized by enlarged cerebral ventricles, gait difficulty, incontinence, and dementia. iNPH usually develops after the sixth decade of life in previously asymptomatic individuals. We recently reported that loss-of-function deletions in CWH43 lead to the development of iNPH in a subgroup of patients, but how this occurs is poorly understood. Here, we show that deletions in CWH43 decrease expression of the cell adhesion molecule, L1CAM, in the brains of CWH43 mutant mice and in human HeLa cells harboring a CWH43 deletion. Loss-of-function mutations in L1CAM are a common cause of severe neurodevelopmental defects that include congenital X-linked hydrocephalus. Mechanistically, we find that CWH43 deletion leads to decreased N-glycosylation of L1CAM, decreased association of L1CAM with cell membrane lipid microdomains, increased L1CAM cleavage by plasmin, and increased shedding of cleaved L1CAM in the cerebrospinal fluid. CWH43 deletion also decreased L1CAM nuclear translocation, suggesting decreased L1CAM intracellular signaling. Importantly, the increase in L1CAM cleavage occurred primarily in the ventricular and subventricular zones where brain CWH43 is most highly expressed. Thus, CWH43 deletions may contribute to adult-onset iNPH by selectively downregulating L1CAM in the ventricular and subventricular zone.

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BACKGROUND: Ventriculogallbladder (VGB) shunts are currently placed as a salvage procedure in treatment of hydrocephalus when all other options are exhausted. Although VGB shunts work well when successfully implanted, they are still rarely used because of the technical challenges with the traditional surgical technique. OBJECTIVE: To implant VGB shunts using a minimally invasive technique that is safer and less technically challenging. METHODS: We discussed our utilization of a percutaneous transhepatic approach to placement of the distal catheter into the gallbladder as a new technique that offers a solution to the established but surgically demanding current approach. We presented a complex patient with multiple failed shunts who underwent placement of a VGB shunt. RESULTS: The shunt was successfully placed and did not incur any complications or require any revisions in 5 yr. CONCLUSION: Given the safety and ease of this minimally invasive approach, we believe percutaneous transhepatic approach in VGB shunts should be considered as a reasonable option in patients with complex hydrocephalus.