Recurrence rates provide evidence for sex-differential, familial genetic liability for autism spectrum disorders in multiplex families and twins

Table 2 Autism recurrence risk by interbirth interval

Group	N	Chi-squared	P value	Adjusted P value
All	332	10.41	1.25e−03	0.011*
Males	188	13.56	2.31e−04	2.08e−03*
Females	144	0.52	0.471	1
FC	129	2.7	0.100	0.903
MO	203	7.37	6.63e−03	0.060
FC, Males	75	1.69	0.194	1
FC, Fems	54	0.67	0.413	1
MO, Males	113	12.08	5.10e−04	4.59e−03*
MO, Fems	90	0.049	0.825	1

Chi-squared statistics and P values are from the whole-model test for logistic regression of affection status of the first child born after the second affected child by the natural log of the interbirth interval (time since the birth of the second affected child) in months. Adjusted P values have been corrected for nine tests. *Adjusted P value ≤0.05. MO, male-only families; FC, female-containing families.

ISSN: 2040-2392