Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
Group I = glycine substitutions within the triple helix, Group II = splice site variants and in frame deletions and duplications, Group III = variants causing haploinsufficiency [5]. Those age under 15 excluded to allow comparison with previous cohort [10]. (PM = post mortem).