Table 3. Clinical and Demographic Comparison of Multiplex and Simplex IS Families with Atleast 4 Members.

Ethnicity was determined by self-report of parental origin. Cobb angles were maximum measurements recorded prior to correction (caw, jah previously unpublished data).

	Multiplex	Simplex
% non-European	9	8
% male probands	18	17
Age at 1st presentation (std dev)	11.7 (+/-2.9)	12.1 (+/-2.8)
Cobb angle (median)	40.3° (39°)	42.1° (42°)