Footnotes

• Contributors FR: diagnosed the disease in the girl, assisted the patient, wrote the first draft of the manuscript and approved the final manuscript as submitted. TO: participated in the clinical assistance of the patient, and reviewed and approved the final manuscript as submitted. EN: participated in the clinical assistance of the patient and approved the final manuscript as submitted. MLDB: contributed to propranolol measurements, contributed to drafting of the manuscript and approved the final manuscript as submitted. GM: responsible for propranolol measurements, contributed to drafting of the manuscript and approved the final manuscript as submitted. MM: participated in the clinical assistance of the patient, and reviewed and approved the final manuscript as submitted. LF: participated in the clinical assistance of the patient, and drafted and approved the final manuscript as submitted.

• Competing interests None declared.

• Patient consent Parental/guardian consent obtained.

• Provenance and peer review Not commissioned; externally peer reviewed.