Implications of the choroid plexus in Niemann-Pick disease Type C neuropathogenesis

•Choroid plexus enlargement was observed in patients with NPC.•Choroid plexus enlargement was associated with the severity of neurodegeneration, neuropsychiatric symptoms, and circulatory markers.•Choroid plexus and thalamic volumes have predictive power to differentiate patients with NPC from other primary neuropsychiatric disorders.•Choroid plexus and thalamic volumes have predictive power to differentiate patients with schizophrenia from patients with bipolar disorder. Niemann-Pick Disease Type C (NPC) is an ultra-rare disorder characterized by progressive psychiatric and neurologic manifestations, with late infantile, juvenile, and adolescent/adult presentations. We examined morphological properties of the choroid plexus, a protective blood-cerebrospinal fluid barrier, in NPC, and their relationship with neurodegeneration, clinical status, and circulatory markers. This study also determined whether choroid plexus morphology differentiates between NPC and more prevalent illnesses, schizophrenia (SZ) and bipolar disorder (BD), which have overlapping psychiatric symptoms with adolescent and adult-onset NPC and are associated with misdiagnosis. Patients with NPC were assessed using neuroimaging, clinical instruments, and plasma protein quantification focusing on inflammatory markers. Morphological properties (i.e., choroid plexus volumes) were compared between patients with NPC (n = 17), SZ (n = 20), BD (n = 24), and healthy controls (HCs, n = 106). Choroid plexus enlargement (p