Study around children with inborn errors of metabolism (IEM) and their healthy siblings. Collection of stool and urine to assess contribution of microbiota to disease severity.

This study aims to collect biological samples (stool and urine) from children with inborn errors of metabolism, IEM (like UCD (urea cycle disorder), PA (propionic aciduria) and MMA (methylmalonic aciduria) and their healthy siblings.

The main focus of the study is to assess the contribution of the intestinal microbiota to disease severity in children that suffer from different forms of IEM and potentially find microbiota targets that could be used in the design of therapeutic/prophylactic agents.

Inclusion Criteria:

• Children or siblings of children that have been diagnosed with one of the following diseases: any type of UCD, PA or MMA

Exclusion Criteria:

• Children or siblings of children that have not been diagnosed with one of the following diseases: any type of UCD, PA or MMA
• use of an investigational drug or device less than 30 days prior to the study, or current enrollment in another investigational drug or device study less than 30 days prior to the study
• considered to be poor attendees or unlikely for any reason to be able to comply with the study procedures, in the opinion of the investigator

The study aims to enroll 40 children that suffer from IEM (UCD, PA, MMA) and their siblings over the course of approximately two years.