PRENATAL-DIAGNOSIS OF NEONATAL ALLOIMMUNE THROMBOCYTOPENIA USING AN ALLELE-SPECIFIC OLIGONUCLEOTIDE PROBE

The prediction of neonatal alloimmune thrombocytopenia (NAIT) in affec ted families is usually based on information about gene frequencies of the antigen systems involved, parental phenotyping, and fetal platele t counts. Recently the use of allele-specific oligonucleotide probe ty ping for Pl(A) (HPA-1) antigens has been described to determine the ri sk of second or subsequent fetuses in families where one infant had th e diagnosis of anti-Pl(A1) (HPA-1a)-mediated NAIT (McFarland et al., 1 991a). This paper describes the first case in which the prenatal diagn osis of Pl(A) (HPA-1) antigen status was accomplished using this techn ology on genomic DNA derived from chorionic villus tissue in the first trimester, and presents the implications of these findings for the cl inical management of this disorder.