Table 1.

Range of age, IQ, asymmetry index values and handedness across the three groups

Variable	ASC (n = 35)			Controls (n = 20)			Siblings (n = 12)			ASC versus siblings		ASC versus controls
	Mean	SD	Range	Mean	SD	Range	Mean	SD	Range
Age (n = 67)	14.48	1.75	12.01 to 18.53	15.27	1.62	12.29 to 17.62	15.30	2.01	12.10 to 18.95
IQ (n = 67)	108.40	16.15	81 to 146	114.05	11.39	83 to 131	114.67	10.78	97 to 129
Asymmetry indices (AI) (n = 67)										F	p	F	p
Splenium AI	0.42	1.55	−2.43 to 3.46	0.60	1.61	−2.88 to 4.27	0.45	1.61	−2.20 to 2.73	1.671	0.203	0.209	0.65
Isthmus AI	−0.93	4.27	−10.00 to 8.65	0.88	3.96	−7.54 to 10.37	0.78	3.09	−4.17 to 7.88	0.046	0.832	0.509	0.479
Posterior midbody AI	0.08	3.45	−12.38 to 7.38	−1.01	3.94	−9.17 to 8.96	−1.25	2.81	−5.04 to 3.79	0.576	0.452	14.342	0.000
Anterior midbody AI	1.01	2.70	−6.71 to 4.27	−1.09	3.09	−8.09 to 6.40	−1.25	2.87	−7.54 to 3.58	0.000	0.983	5.341	0.025
Rostral body AI	0.71	3.40	−7.28 to 7.90	0.85	3.77	−5.24 to 7.15	0.18	3.95	−7.23 to 4.29	0.441	0.511	0.864	0.357
Genu AI	0.87	3.62	−6.55 to 8.21	0.16	3.43	−9.33 to 7.22	0.65	3.80	−5.30 to 6.76	2.822	0.101	0.015	0.903
Rostrum AI	7.85	13.24	−40.9 to 21.4	−5.20	8.69	−21.69 to 12.37	−6.68	2.00	−35.11 to 15.88	0.000	0.997	0.17	0.898
Total volume AI	0.04	1.50	−4.30 to 3.45	−0.12	1.60	−3.49 to 3.14	−0.15	1.24	−2.49 to 2.36	0.86	0.36	2.54	0.118
Handedness (n = 62)	51.16	59.81	−89.5 to 100	69.19	44.56	−70 to 100	86.20	14.37	57.89 to 100	105.5	0.082	259	0.292

Handedness was assessed using the Edinburgh Handedness Inventory. Values range from +100 (strongest right-handedness) to -100 (strongest left-handedness). Corpus callosum asymmetry index values > 0 indicate rightward asymmetry and values < 0 indicate leftward asymmetry. Differences in sample size are due to fewer available measures on handedness in the three groups with n = 33 for ASC, n = 19 controls and n = 10 for siblings