Prevalence and Determinants of Obesity in PKU Patients

NCT07703020 | Enrolling By Invitation

• 1 other identifier: 2024-01596
• Study Type: observational
• Target: 100
• Locations: 1 country
• Sites: 1

Brief Summary

This observational cross-sectional multicenter study aims to assess the prevalence of overweight and obesity in adult patients with phenylketonuria (PKU) and to identify associated risk factors. Adult PKU patients followed in metabolic centers in Switzerland and Austria will be evaluated using clinical data, laboratory parameters, and standardized questionnaires addressing diet, physical activity, and psychological factors. The study seeks to better understand contributors to weight gain in this population to inform preventive strategies.

Conditions

Phenylketonuria (PKU)

Keywords

phenylalanine; obesity; diet

Outcome Measures

Primary Outcomes (1)

• Prevalence of overweight and obesity in adult PKU patients

  Defined according to WHO BMI categories (overweight: 25.0-29.9 kg/m²; obesity class I-III: ≥30.0 kg/m²)

  At enrollment

Secondary Outcomes (14)

• Dietary adherence in adult PKU patients (self-reported adherence questionnaire)

  At enrollment

• Dietary intake in adult PKU patients (24-hour dietary recall)

  At enrollment

• Disordered eating behaviors (Eating Disorder Examination Questionnaire, EDE-Q)

  At enrollment

• Depressive symptoms (Patient Health Questionnaire-9, PHQ-9)

  At enrollment

• Physical activity level (Global Physical Activity Questionnaire, GPAQ)

  At enrollment

Study Arms (2)

Adult PKU patients with overweight/obesity (BMI ≥ 25 kg/m²)

This cohort includes adult patients (≥18 years) with confirmed phenylketonuria presenting with overweight or obesity according to WHO BMI criteria. This is an observational group with no intervention. Participants will undergo a one-time assessment including standardized questionnaires evaluating physical activity (GPAQ), psychological status (PHQ-9), and eating behaviors (EDE-Q), as well as a dietary assessment (24-hour recall). Clinical, demographic, treatment-related (e.g., dietary adherence, sapropterin use), and retrospective laboratory data (e.g., phenylalanine levels and metabolic parameters) will be collected to identify factors associated with excess body weight.

Adult PKU patients with normal weight (BMI <25 kg/m²)

This cohort includes adult patients (≥18 years) with confirmed phenylketonuria and normal body weight. This is an observational group with no intervention. Participants will complete the same one-time assessments as Group 1, including standardized questionnaires (GPAQ, PHQ-9, EDE-Q), dietary assessment (24-hour recall), and collection of clinical, demographic, treatment-related, and retrospective laboratory data. This group will serve as a comparator to identify factors associated with overweight and obesity in the PKU population.

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Participants will be recruited from adult metabolic clinics and inherited metabolic disease centers in Switzerland (CHUV in Lausanne, HUG in Geneva, Inselspital in Bern, University Hospital Zurich, University Hospital Basel, Kantonsspital St. Gallen) and Austria (AKH Universitätsklinikum, Vienna). This population represents adults with PKU who are actively followed in specialized reference centers, reflecting a mix of patients treated since birth through newborn screening programs and those diagnosed later in life

You may qualify if:

• Confirmed diagnosis of phenylketonuria (PKU) by biochemical and/or molecular testing.
• Age ≥ 18 years.
• Ability to provide written informed consent.

You may not qualify if:

• Pregnant or lactating women.
• Inability to follow the study procedures (e.g., due to language barriers).
• Eligible participants who refuse to be informed of any important health concern discovered during the study.
• Investigators, their family members, employees, or anyone with a personal link to the investigator other than a doctor-patient relationship.

Sponsors & Collaborators

• Christel Tran: lead

Study Sites (1)

Lausanne University Hospital

Lausanne, Canton of Vaud, 1011, Switzerland

Location

Related Publications (1)

• Tankeu AT, Pavlidou DC, Superti-Furga A, Gariani K, Tran C. Overweight and obesity in adult patients with phenylketonuria: a systematic review. Orphanet J Rare Dis. 2023 Feb 22;18(1):37. doi: 10.1186/s13023-023-02636-2.

  PMID: 36814307 BACKGROUND

MeSH Terms

Conditions

Phenylketonurias; Obesity

Condition Hierarchy (Ancestors)

Brain Diseases, Metabolic, Inborn; Brain Diseases, Metabolic; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Amino Acid Metabolism, Inborn Errors; Metabolism, Inborn Errors; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Metabolic Diseases; Nutritional and Metabolic Diseases; Overweight; Overnutrition; Nutrition Disorders; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: CROSS SECTIONAL
• Target Duration: 2 Years
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: PD-Dr

Study Record Dates

• First Submitted: March 24, 2026
• First Posted: July 14, 2026
• Study Start: March 1, 2026
• Primary Completion (Estimated): February 1, 2028
• Study Completion (Estimated): February 1, 2029
• Last Updated: July 14, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

CH (1)