Prenatal diagnosis of neonatal alloimmune thrombocytopenia using an allele-specific oligonucleotide probe

The prediction of neonatal alloimmune thrombocytopenia (NAIT) in affected families is usually based on information about gene frequencies of the antigen systems involved, parental phenotyping, and fetal platelet counts. Recently the use of allele-specific oligonucleotide probe typing for PlA (HPA-1) antigens has been described to determine the risk of second or subsequent fetuses in families where one infant had the diagnosis of anti-PlA1 (HPA-1a)-mediated NAIT (McFarland et al., 1991a). This paper describes the first case in which the prenatal diagnosis of PlA (HPA-1) antigen status was accomplished using this technology on genomic DNA derived from chorionic villus tissue in the first trimester, and presents the implications of these findings for the clinical management of this disorder.