Clinical Trial Details
— Status: Withdrawn
Administrative data
| NCT number |
NCT02899598 |
| Other study ID # |
2012-55 |
| Secondary ID |
|
| Status |
Withdrawn |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
July 27, 2023 |
| Est. completion date |
July 27, 2023 |
Study information
| Verified date |
July 2023 |
| Source |
Assistance Publique Hopitaux De Marseille |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Neonatal thrombocytopenia isoimmunization maternal-fetal is related to maternal immunization
against fetal platelet antigens with paternal origin not present in the mother. It is
considered the equivalent of hemolytic disease of the newborn. The incidence of this disease
is about 1 in 800-1000 births. The most severe forms associated petechiae, purpura or
cephalhematoma at birth with a major risk of cerebral hemorrhages (20% to 25% of cases) can
cause the death of the child (15%) or severe neurological troubles (15-30%) Biologic
diagnosis requires the detection of anti-platelet antibodies with maternal determination of
platelet phenotypes and genotypes of the two parents.
The objective of this work is to develop specific molecular tools to fetal platelet
genotyping from maternal blood. We are particularly interested to antigens HPA-1, HPA-5 ,
HPA-3 and HPA-4. We evaluate the sensitivity and specificity of this test by comparing these
results with those obtained from an invasive sampling of amniotic fluid.
This is a prospective study to assess the technical and diagnostic performance of a new
molecular method noninvasive prenatal diagnosis of platelet genotyping.
Description:
Neonatal thrombocytopenia isoimmunization maternal-fetal is related to maternal immunization
against fetal platelet antigens with paternal origin not present in the mother. It is
considered the equivalent of hemolytic disease of the newborn. The incidence of this disease
is about 1 in 800-1000 births. The most severe forms associated petechiae, purpura or
cephalhematoma at birth with a major risk of cerebral hemorrhages (20% to 25% of cases) can
cause the death of the child (15%) or severe neurological troubles (15-30%) Biologic
diagnosis requires the detection of anti-platelet antibodies with maternal determination of
platelet phenotypes and genotypes of the two parents. When it is diagnosed, genetic
counseling to the couple for a future pregnancy is necessary because the risk of recurrence
is important and severity increases with the number of pregnancies. The risk depends on the
nature of paternal antigens, homozygous or heterozygous. In case of heterozygosity, prenatal
diagnosis is based on fetal platelet genotyping by an invasive procedure (amniocentesis or
chorionic villus sampling) associated with a risk of fetal loss. The alloantibodies
responsible for fetal damage are directed against platelet alloantigens: this is HPA system
(human platelet alloantigen). 24 alloantigens have been described and 12 of them have a
biallelic polymorphism (a: the most frequent allele and b the rare allele) divided into 6
groups (HPA-1, 2, 3, 4, 5, and 15). The genotype-phenotype correlations were performed for 22
of the 24 alloantigens and show that the antigenic polymorphism results from the presence of
a SNP (single nucleotide polymorphism-).
In 1997, Lo et al showed the presence of 3-6% of fetal DNA in maternal blood. This discovery
led to the development of methods of non-invasive prenatal diagnosis: 1/ the determination of
fetal Rhesus 2/ fetal sex by real-time quantitative PCR.
The objective of this work is to develop specific molecular tools to fetal platelet
genotyping from maternal blood. We are particularly interested to antigens HPA-1, HPA-5 ,
HPA-3 and HPA-4. We evaluate the sensitivity and specificity of this test by comparing these
results with those obtained from an invasive sampling of amniotic fluid.
This is a prospective study to assess the technical and diagnostic performance of a new
molecular method noninvasive prenatal diagnosis of platelet genotyping.
