Figure 2.

Pedigrees used in the linkage and linkage-disequilibrium studies. Asterisks and triangles indicate individuals from whom DNA samples were available. Individuals marked with asterisks were used in linkage and linkage-disequilibrium analyses, and those marked with triangles provided information for linkage-disequilibrium studies only. Individuals affected with hydrolethalus syndrome are marked with blackened symbols. In most cases, the pregnancy was terminated, after prenatal diagnosis by ultrasound. Only the first affected children in families 3, 8, 13, and 14 were delivered. SB=stillborn (hydrolethalus-syndrome status not known), 18tr=termination of a pregnancy with trisomy 18 but not hydrolethalus syndrome.