Prenatal diagnosis for congenital afibrinogenemia.

(A) Family tree. SA: spontaneous abortion. The arrow indicates the fetus undergoing prenatal diagnosis (proband). (B) Partial sequence ofFGB exon 8 demonstrating the FGBTrp467Stop (W467X; TGG>TAG) mutation. Top panel, heterozygote; bottom panel, homozygote Trp467Stop. (C) Amino acid sequence of the fibrinogen beta chain. The Palestinian Trp467Stop mutation identified in this study is shown (bold) as well as the Trp470Stop (W470X) “fibrinogen Mount Eden” mutation19 and 3 missense mutations18 20: Leu383Arg, Gly430Asp, and Tyr467Gly. Amino acids encoded by odd-numbered exons 1, 3, 5, and 7 are in normal font; those encoded by even-numbered exons 2, 4, 6, and 8 are highlighted in gray. Amino acids encoded by codons separated in 2 consecutive exons are underlined. Amino acids are numbered from the initiator methionine; those included in the signal peptide are in bold.