. Author manuscript; available in PMC: 2015 Aug 1.

Published in final edited form as: J Autism Dev Disord. 2014 Aug;44(8):2013–2025. doi: 10.1007/s10803-014-2081-2

Table 5.

Twin similarity and bivariate heritability for cross-construct analyses.

Measure	Sub-sample	Twin Pairs	Twin similarity	Bivariate heritability (h²_g)
		MZ/DZ	B₁ (95% CI)	B₂ (95% CI)
SCQ – SCI predicts RRB
	ASD	284	−.01 (−.13, .11)	1.00 (.70, 1.30)^*
	≥97^th%	241	−.01 (−.22, .20)	.87 (.57, 1.17)^*
SCQ – RRB predicts SCI
	ASD	284	−.11 (−.30, .08)	1.00 (.66, 1.34)^*
	≥97^th%	259	−.30 (−.57, .03)	.81 (.50, 1.11)^*
SRS – SCI predicts RRB
	ASD	152	.23 (.03, .43)^ˆ	1.18 (.74, 1.62)^*
	≥97^th%	118	.16 (−.24, .56)	1.12 (.64, 1.60)^*
SRS – RRB predicts SCI
	ASD	152	.23 (−.01, .46)	1.21 (.71, 1.71)^*
	≥97^th%	138	.05 (−.24, .34)	.99 (.55, 1.43)^*

^ˆ

p<.05

p<.001.

SCQ=Social Communication Questionnaire. SRS=Social Responsiveness Scale. SCI=Social communication/interaction. RRB=Restricted/Repetitive Behavior.