Linkage analysis of breast cancer among Utah and Dutch families using the sib-pair test.

The n a t u r e of t h e g e n e t i c f a c t o r s presumed to c o n t r i b u t e t o t h e development of b r e a s t cancer is unknown (see King, 1984, for a review). E l u c i d a t i n g t h e s e g e n e t i c factors is d i f f i c u l t because b r e a s t cancer is a heterogeneous d i s e a s e w i t h l a te ageo f o n s e t and o c c u r s predominant ly i n women. Linkage a n a l y s i s may c l a r i f y g e n e t i c f a c t o r s of a d i s e a s e . Linkage between a common d i s e a s e and a marker l o c u s may be taken as evidence that a major gene i n f l u e n c e s d i s e a s e s u s c e p t i b i l i t y (see, f o r example, MacCluer e t a l . , 1984) . The sib-pair test of l i n k a g e (Haseman and E l s t o n , 1972) is f a s t , does n o t r e q u i r e i n i t i a l s p e c i f i c a t i o n of a g e n e t i c model and may be used as an explorat o r y method to i n d i c a t e i f a major gene i n f l u e n c e s d i s e a s e s u s c e p t i b i l i t y ( E l s t o n , 1984) . This paper r e p o r t s t h e r e s u l t s of t h e s i b p a i r t e s t a p p l i e d t o breast cancer d a t a from Genet ic Analys is Workshop I V .