Burden of illness of aromatic L-amino acid decarboxylase deficiency: a survey of physicians in Southern Europe

Abstract

Background

Aromatic L-amino acid decarboxylase deficiency (AADCd) is an ultra-rare genetic neurometabolic disorder caused by mutations in the DDC gene.

Objective

This retrospective, noninterventional study was designed to describe the burden of AADCd including the associated healthcare resource utilization in Southern Europe.

Methods

Eleven clinicians completed a patient case study survey for patients with AADCd currently or previously under their care, followed by an interview with each clinician to assess healthcare resource utilization, patient characteristics, and symptoms.

Results

Clinicians provided data for 20 patients with AADCd, of whom 60% were male. All patients experienced movement disorders, 90% exhibited developmental delay, 85% reported sleeping problems, and 80% experienced gastrointestinal problems. The symptoms varied with disease severity. Patients with AADCd received care from more than 16 different specialists including both medical and paramedical healthcare professionals. Hospitalizations and visits to accident and emergency departments were also frequent.

Conclusion

In terms of symptoms and healthcare resource utilization, the burden of illness of AADCd is substantial. This study provides insights into several aspects of the disease that are difficult to ascertain from published case reports.

Keywords:

• Aromatic L-amino acid decarboxylase deficiency
• AADC deficiency
• burden of disease
• clinician survey
• healthcare resource utilization
• patient case study survey

Transparency

Declaration of funding

This study was funded by PTC Therapeutics, Inc.

Declaration of financial/other relationships

Priya Patel, Philippa Rowan, and Samira Saberian are employees of OPEN Health. Igor Beitia Ortiz de Zarate and Florence Hammes are current or former employees of PTC Therapeutics France, Fernando Fernandez Cortes is an employee of PTC Therapeutics Spain. Katharina Buesch is an employee of PTC Therapeutics Switzerland. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Florence Hammes, Igor Beitia Ortiz de Zarate and Katharina Buesch were involved in the conception and design. Samira Saberian, Philippa Rowan, and Priya Patel developed the clinician survey, and carried out the data analysis. All authors participated in interpretation of the data. All authors were involved in revising the paper critically for intellectual content and the final approval of the version to be published. All authors agreed to be accountable for all aspects of the work.

Acknowledgements

Medical writing and editorial support was provided by Tove Anderson, PhD, of PharmaGenesis London, London, UK, and was funded by PTC Therapeutics.