Footnotes

• Handling editor Josef S Smolen

• Contributors HB and MEO conceived the idea for the study and interpreted the results. HB and ALN performed the clinical follow-up of the patient and her child. DJW and NB performed the laboratory analysis. HB, DJW, NB and MEO critically reviewed the paper. All authors approved the manuscript.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

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