Redefining first trimester miscarriage

Celocentesis for Early Prenatal Diagnosis in Couples at-Risk for β-Thalassemia and Sicilian (δβ)0-Thalassemia

The procedures commonly used for prenatal diagnosis (PND) of thalassemia are villocentesis or amniocentesis, respectively, at the 11th and 16th weeks of gestation. Their main limitation is essentially due to the late gestation week in which diagnosis is performed. The celomic cavity is accessible between the 7th and 9th weeks of gestation and it has been demonstrated that it contains embryonic erythroid precursor cells as a source of fetal DNA for earlier invasive PND of thalassemia and other monogenic diseases. In this study, we report the use of celomatic fluids obtained from nine women with high-risk pregnancies for Sicilian (δβ)⁰-thalassemia [(δβ)⁰-thal] deletion (NG_000007.3: g.64336_77738del13403) and β-thalassemia (β-thal). Fetal cells were isolated by a micromanipulator, and nested polymerase chain reaction (PCR) and short tandem repeats (STRs) analysis were performed. Prenatal diagnosis was successfully performed in all examined cases. One fetus was a compound heterozygote for (δβ)⁰- and β-thal, three fetuses were found to be carriers of β-thal, four fetuses carriers of a Sicilian δβ deletion, and one fetus without parental mutations. Accidentally, a rare case of paternal triploidy was observed. The genotypic analysis, carried out both by amniocentesis and on abortive tissue or after birth, showed concordance with results obtained on fetal celomic DNA. Our results unequivocally show that fetal DNA can be obtained by nucleated fetal cells present in the celomatic fluid and demonstrate, for the first time, that PND of Sicilian (δβ)⁰-thal and β-thal is feasible at an earlier time in pregnancy than other procedures.

Celomic Fluid: Laboratory Workflow for Prenatal Diagnosis of Monogenic Diseases

BACKGROUND

Celomic fluid can be considered as an ultra-filtrate of maternal serum, containing a high protein concentration, urea, and many other molecules. It is an important transfer interface and a reservoir of nutrients for the embryo. Celomic fluid contains fetal cells that can be used for prenatal diagnosis of monogenic diseases in an earlier gestational period than villocentesis and amniocentesis.

OBJECTIVE

The purpose of this study was to evaluate the characteristics of celomic fluid and to establish a workflow laboratory procedure for very early prenatal diagnosis of monogenic diseases.

METHODS

Three hundred and eighty-five celomatic fluids were collected between the seventh and tenth week of gestation. We sampled 1 mL of celomic fluid in all cases. The embryo-fetal erythroid precursor cells were selected by the anti-CD71 microbead method or by a direct micromanipulator pick-up on the basis of their morphology. We amplified the extracted DNA using a nested polymerase chain reaction. Primers for short tandem repeat amplification were used to perform a quantitative fluorescent polymerase chain reaction evaluation to control maternal contamination.

RESULTS

We observed maternal contamination in 95% of celomic fluids with a range between 5 and 100%. No fetal cells were observed in 0.78% of celomic fluids. The number of fetal cells ranged from a few units to several hundred. Isolation of embryo-fetal erythroblasts selected by the micromanipulator made diagnosis feasible in all cases.

CONCLUSIONS

The selection of fetal cells by a micromanipulator and nested polymerase chain reaction analysis made celomatic fluid suitable for early prenatal diagnosis of monogenic disorders even in the presence of high maternal contamination and few fetal cells. The procedure reported in this study provides the opportunity for the use of celomic fluid sampled by celocentesis as an alternative to chorionic villi sampling and amniocentesis, to allow invasive prenatal diagnosis at a very early stage of pregnancy.

Genetics of recurrent pregnancy loss among Iranian population

Background

Recurrent pregnancy loss (RPL) is one of the most common reproductive disorders which is defined as the occurrence of recurrent miscarriage before 24 weeks of gestation and is observed among 1%–5% of women.

Methods

Various factors are associated with RPL such as immunological disorders, maternal age, obesity, alcohol, chromosomal abnormality, endocrine disorders, and uterine abnormalities. About half of the RPL cases are related with chromosomal abnormalities. Therefore, RPL genetic tests are mainly limited to karyotyping. However, there is a significant proportion of RPL cases without any chromosomal abnormalities that can be related to the single‐gene aberrations. Therefore, it is required to prepare a diagnostic panel of genetic markers besides karyotyping.

Results

In the present review, we have summarized all the significant reported genes until now which are associated with RPL among Iranian women. We categorized all the reported genes based on their cellular and molecular functions in order to determine the molecular bases of RPL in this population.

Conclusion

This review paves the way of introducing a population‐based diagnostic panel of genetic markers for the first time among Iranian RPL cases. Moreover, this review clarifies the genetic and molecular bases of RPL in this population.

Early Pregnancy Losses: Review of Nomenclature, Histopathology, and Possible Etiologies

Miscarriage is a frequent complication of human pregnancy: ∼50% to 70% of spontaneous conceptions are lost prior to the second trimester. Etiology of miscarriage includes genetic abnormalities, infections, immunological and implantation disorders, uterine and endocrine abnormalities, and lifestyle factors. Given such variability, knowledge regarding causes, pathophysiological mechanisms, and morphologies of primary early pregnancy loss has significant gaps; often, pregnancy losses remain unexplained. Pathologic evaluation of miscarriage tissue is an untapped source of knowledge. Although miscarriage specimens comprise a significant part of pathologists' workload, information reported from these specimens is typically of minimal clinical utility for delineating etiology or predicting recurrence risk. Standardized terminology is available, though not universally used. We reintroduce the terminology and review new information about early pregnancy losses and their morphologies. Current clinical terminology is inconsistent, hampering research progress. This review is a resource for diagnostic pathologists studying this complex problem.