Among families with autism, examination of affected sibpairs revealed significant paternal (P =
0.007), but not maternal (P = 0. 75), identity-by-descent sharing at D7S640. Significant linkage
disequilibrium was detected with paternal (P = 0.02), but not maternal (P = 0.15), transmissions at
D7S1824 in multiplex and singleton families (Ashley-Koch
A et al, 1999).