---
title: Link bacterial gene with constipation
nct_id: NCT07175922
status: RECRUITING
sponsor: Vertero Therapeutics
study_type: OBSERVATIONAL
canonical_url: "https://parkinsonspathways.com/trial/NCT07175922"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT07175922"
last_fetched: "2026-05-10T14:03:22.417Z"
source: "Parkinson's Pathways (curated)"
---
# Link bacterial gene with constipation

**Goal (in five words):** Link bacterial gene with constipation

**Official Title:** Evaluation of csgA Prevalence, Gene Expression and Week-to-Week Variability in Participants With Parkinson's Disease and a History of Gastrointestinal Dysfunction

**Trial ID:** [NCT07175922](https://clinicaltrials.gov/study/NCT07175922)

## Key Facts

- **Status:** RECRUITING
- **Study Type:** OBSERVATIONAL
- **Sponsor:** Vertero Therapeutics
- **Target Enrollment:** 200 participants
- **Start Date:** 2025-09-25
- **Completion Date:** 2026-03-30
- **Conditions:** Parkinsons Disease (PD)

## Summary For Families

The goal is to find out how common and active a bacterial gene called csgA is in people with Parkinson's who have current or past gastrointestinal problems, and whether its levels change week to week. The approach is observational, using repeated stool samples to measure csgA prevalence and gene expression, since csgA makes bacterial amyloid proteins that in lab models can encourage alpha-synuclein to clump, so researchers want to see if gut bacterial activity lines up with PD-related gut symptoms. No treatment is given, the study just tracks microbiome signals and symptoms over time. They are looking for people age 18 to 80, diagnosed with Parkinson's within the past 10 years who have or had constipation or other GI dysfunction, must be able to complete study procedures in Dutch, and cannot have major GI disease, recent significant GI infection or surgery, certain eating disorders, or systemic antibiotic use in the prior 6 months.

## Eligibility

- **Minimum age:** 18 Years
- **Maximum age:** 80 Years
- **Sex:** ALL

### Full Criteria

```
Inclusion Criteria:

* Between 18-80 years of age at ICF signing (inclusive)
* A diagnosis of PD within 10 years from the time of ICF signing
* Current or history of gastrointestinal (GI) dysfunction or constipation based on screening assessment
* All participants must understand and provide written informed consent prior to any study specific procedures
* Able to speak, read, and understand study procedures in Dutch sufficiently to allow completion of all study assessments

Exclusion Criteria:

* Any known GI disorder if deemed clinically significant by the investigator. GI disorders may include, but are not limited to: Crohn's disease, ulcerative colitis, celiac disease, irritable bowel syndrome, or lactose intolerance
* Recent GI infection in the past 3 months if deemed clinically significant by the investigator.
* Major GI surgery (excluding appendectomy/cholecystectomy), such as bariatric surgery, gastrectomy, esophagectomy, vagotomy, small intestine surgeries, any type of colectomy, colostomy and anorectal surgeries if deemed clinically significant by the investigator
* Any known current or past eating disorder if deemed clinically significant by the investigator
* Use of systemic antibiotics within 6 months prior to enrollment
```

## Locations (1)

- Center for Human Drug Research, Leiden, Netherlands _(52.1583, 4.4931)_
  - P.H.C. Kremer — (CONTACT) — +31 0715246400 — clintrials@chdr.nl

## Central Contacts

- P.H.C. Kremer — (CONTACT) — +31 0715246400 — clintrials@chdr.nl

---

*Canonical: https://parkinsonspathways.com/trial/NCT07175922*  
*HTML version: https://parkinsonspathways.com/trial/NCT07175922*  
*Source data: https://clinicaltrials.gov/study/NCT07175922*