Infants and young children up to 10 years of age with a complex condition involving the gastrointestinal tract are at risk of poor nutritional status, including faltering growth. Due to the complex condition, standard nutrition is often not tolerated and causes gastrointestinal symptoms.

Formulas in which protein is replaced by its smallest elements, amino acids are easier for the body to digest and absorb. These formulas might be tolerated better and reduce gastrointestinal symptoms in infants and young children with complex conditions.

The objectives of the present, exploratory study are to gain clinical evidence related to the nutritional status and gastrointestinal tolerance in infants and young children with complex conditions receiving Neocate as their primary source of nutrition. Additional objectives are to describe the nutritional and pharmacological management of these infants and young children. Study duration for each participant will be 52 weeks at maximum.

Inclusion Criteria:

• Infants and young children aged from 0 up to and including 10 years of age.
• Severe impairment of at least 1 organ system
• Impairment of the gastrointestinal tract, i.e. gastrointestinal disease, congenital abnormality, surgical resection, or gastrointestinal dysfunction (including symptoms of gastrointestinal dysmotility or malabsorption).
• Receiving at least 75% of their energy intake from Neocate (Neocate Infant or Junior powdered (marketed) product) at the time of study entry (V1).
• Expected to receive at least 75% of their energy intake from the study product for at least 4 weeks from study entry (V1).
• Written informed consent provided by parents/guardians and assent by the child, if applicable, according to local law.

Exclusion Criteria:

• Infants born with a gestational age <37 weeks that are <40 weeks corrected age at the time of study entry (V1).
• Infants or children with endoscopically confirmed eosinophilic oesophagitis and prescribed an amino acid-based formula only for the management of the eosinophilic oesophagitis.
• Infants or children with a medical diagnosis that includes only (suspected) cow's milk allergy and/or multiple food allergy.
• Infants or children with renal dysfunction, e.g. acute or chronic kidney failure or kidney cancer.
• Infants or children with thyroid disorder or parathyroid disorder.
• Expected to receive parenteral nutrition during intervention from study entry (V1).
• Participation in any other studies involving investigational or marketed products concomitantly or within 1 month prior to study entry (V1).
• Investigator's uncertainty about the willingness or ability of the parents/guardians to comply with the protocol requirements.