Table 1

Family structures and phenotypes of the two samples analysed

	Number of families with affected children
	Asthma	Positive RAST	Atopic dermatitis	Rhinitis
RAST, radioadioallergosorbent test.
Sample A (135 families)
1 affected child	0	35	51	47
2 affected children	135	73	68	74
Total	135	108	119	121
Sample B (100 families)
1 affected child	31	36	33	36
2 affected children	45	40	34	35
3 affected children	12	7	6	8
Total	88	83	73	79