Table 3

Calculated segregation ratios. Sib recurrence risk derived from segregation analysis

	No of pedigree	Sibs	Affected sibs	R	T	J	Q	Single incomplete	Var S	Multiple incomplete	Var M
Segregation analysis calculated by the methods of Fisher⁸ and Davie.⁹
R=number of affected subjects in all sibships, T=total number of subjects in all sibships, J=number of sibships with exactly one proband, Q=number of sibships with exactly two probands.
Whole group
OFCD	74	99	8	82	173	68	5	0.081	0.001	0.133	0.002
Non-OFCD	12	9	0	12	21	12	0	0.000	0.000	0.000	0.000
Unclassifiable	22	26	0	22	48	22	0	0.000	0.000	0.000	0.000
Total	108	134	8	116	242	102	5	0.060	0.000	0.100	0.001
OFCD
Female	49	69	3	52	118	46	3	0.043	0.001	0.083	0.002
Male	59	65	5	64	124	56	2	0.077	0.001	0.118	0.002
Isolated malformation	52	64	3	55	116	50	2	0.047	0.001	0.076	0.002
Laterality
Bilateral	53	73	5	58	126	49	4	0.068	0.001	0.117	0.002
Unilateral	55	61	3	58	116	53	1	0.049	0.001	0.079	0.002
Left	29	30	0	29	59	29	0	0.000	0.000	0.000	0.000
Right	26	31	3	29	57	24	1	0.097	0.003	0.152	0.005
Parents normal
Bilateral	50	69	2	52	119	49	1	0.029	0.000	0.043	0.001
Unilateral	55	61	3	58	116	53	1	0.049	0.001	0.079	0.002
Parent affected	3	4	3	6	7	0	3	0.750	0.047	0.857	0.020