Fig. 1.

Flow diagram summarizing the recruitment process of HBM index cases and then their relatives and spouses. UK United Kingdom, DXA dual X-ray energy absorptiometry, HBM high bone mass. All participants with HBM were pooled (258 index cases, 94 relatives, 3 spouses) shown in octagonal boxes filled with grey dots. All participants unaffected by HBM were pooled (142 unaffected relatives and 58 unaffected spouses) shown in hatched boxes. Two centres recruited prospectively on a case-by-case when qualifying DXA scans arose as part of routine clinical practice