Bertrand G, Bianchi F, Chenet C, Martageix C, Blanchet P, Bäumler M, Kaplan C. New mutation in the platelet beta3-integrin gene: implication for the diagnosis of fetomaternal alloimmunization.
Transfusion 2007;
46:2138-41. [PMID:
17176326 DOI:
10.1111/j.1537-2995.2006.01043.x]
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Abstract
BACKGROUND
Fetal ventriculomegaly is a relatively common finding and fetomaternal alloimmune thrombocytopenia may be one of the causes.
STUDY DESIGN AND METHODS
Such a case discovered at 21 weeks of gestation leading to platelet (PLT) immunologic testing is reported here. PLT genotyping was performed by polymerase chain reaction (PCR)-sequence-specific primers (SSPs) method and PCR-restriction fragment length polymorphism (RFLP) analysis. Serologic investigation was done with the monoclonal antibody-specific immobilization of PLT antigens technique.
RESULTS
The mother was found to be HPA-1b homozygous and the father HPA-1a homozygous with PCR-SSP, but the mother was found to be HPA-1 heterozygous by phenotyping. This result was confirmed by PCR-RFLP. Sequencing of the glycoprotein IIIa exon 3 revealed a heterozygous mutation 262T > C, which does not induce an amino acid change. It is localized in the sequence of the antisense primer of the HPA-1 PCR-SSP, inducing the sole amplification of the DNA copy bearing the HPA-1b allele.
CONCLUSION
Even if such mutations are a rare event, PLT phenotyping is still of interest to avoid rare false PLT typing assignation, the unknown polymorphism being only discovered by such a combination of techniques.
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