aMetabolic Bone Disorders Unit, National Institute of Dental and Craniofacial Research, National Institutes of Health

bPediatric Endocrinology Inter-Institute Training Program, National Institute of Child Health and Development, National Institutes of Health, Bethesda, Maryland, USA

Correspondence to Alison M. Boyce, MD, Building 30 Room 228 MSC 4320, Bethesda, MD 20892, ORCID ID: 0000-0002-2725-2908. E-mail: [email protected]