"Metabolomics from*lysosomal organelles*isolated*from fresh peripheral blood of CLN3 patients and healthy controls and/or allele carriers".*A proof of principle study.

CLN3 mutations are the most common cause of Juvenile Neuronal Ceroid
Lipofuscinosis (JNCL) and childhood dementia in the western world. The CLN3
gene encodes a lysosomal transmembrane protein which structure and function
remains to be fully elucidated. Together with lysosomal enzymes, lysosomal
membrane proteins are essential for the degradation of proteins, lipids,
oligosaccharides, and nucleic acids, and the recycling and re-supply of
building blocks to be used by the cell. The non-enzymatic roles of these
lysosomal transmembrane proteins vary widely and include e.g. ion channels (to
maintain lysosomal ion homeostasis, regulate lysosomal membrane voltage, and
maintain luminal acidic pH), nutrient transporters e.g. for amino acids, lipids
e.a., proteins that serve roles as tethers for inter-organellar communication
and proteins that serve roles in trafficking and/or vesicular fusion. Today,
there are no treatments for JNCL(or, Batten Disease), and there is a great need
to understand CLN3 function and the underlying disease mechanisms. We believe
these can be unraveled by the analysis of the disease-specific lysosomal
metabolome, proteome, and lipidome. Patient peripheral white blood mononuclear
cells (PBMCs) provide a source of cells that can be collected with least burden
to patients and CLN3 patient PBMCs could prove vital for devising biomarkers
and/ or to control effectiveness of potentially novel treatment strategies

We aim to define components which are critical for lysosomal homeostasis and
are affected in CLN3 disease. To this end we will perform multi-omics analysis
of lysosomes isolated from fresh peripheral white blood mononuclear cells
(PBMCs) of patients with juvenile CLN3 disease. We will quantify 1) lysosomal
proteins, 2) lysosomal metabolites and 3) lysosomal lipids, in comparison to
controls. We will also compare the results with those already obtained using
the lysoIP methodology in human CLN3 cellular models and tissues from animal
models including brain of a CLN3-deficient mouse mode

This study is a pilot study and essential to address the question whether we
can apply our multi-omics method using patient PBMCs to achieve a fundamental
understanding of the processes occurring in the lysosomes of CLN3 patients

The proposed study involving CLN3 patients is a pilot study. The total number
of participants would be determined by confirmed consent, availability and
number of potential participants, and feasibility in terms of organizing
visits. Ideally, we will try and schedule several patients within a short time
frame. Because of the variability of the disease we estimate that 10
participants with Batten disease are needed. We would additionally request
relevant demographic, genetic and clinical data that should be available in the
participants' medical records (age, gender, diagnosis, genetic diagnosis,
clinical presentation and regular medications). There is no immediate benefit
for participants although individual results will be fed back, if requested. We
will also provide a summary statement of significant findings.