Distribution of diandric and digynic triploidy depending on gestational age.

PURPOSE: To establish the distribution of diandric and digynic triploidy depending on gestational age. METHODS: 107 triploid samples tested prospectively in a single genetic department during a four-year period were analyzed for parental origin of triploidy by Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) (n=95) with the use of matching parental samples or by MS-MLPA (n=12), when parental samples were unavailable. Tested pregnancies were divided into three subgroups with regard to the gestational age at spontaneous pregnancy loss: <11 gestational weeks, 11-14 gestational weeks, and >14 gestational weeks. RESULTS: Diandric triploidy constituted overall 44.9% (46.5% in samples miscarried <11 gestational weeks, 64.3% in samples miscarried between 11 and 14 gestational weeks, and 27.8% in pregnancies which survived >14 gestational weeks). CONCLUSIONS: The distribution of diandric and digynic triploidy depends on gestational age. The majority of diandric triploid pregnancies is lost in the first trimester of pregnancy. In the second trimester, diandric cases are at least twice less frequent than digynic ones.

Triploid pregnancy-Clinical implications.

Triploidy is a life-limiting genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric triploidy) or maternal origin (digynic triploidy). Triploidy affects around 1%-2% of all conceptions. The majority of cases is miscarried at early developmental stages. In consequence of genomic imprinting, parental origin affects the phenotype of triploid pregnancies as well as the prevalence and spectrum of related maternal complications. Distinctive ultrasound features of both triploid phenotypes as well as characteristic patterns of biochemical markers may be useful in diagnosis. Molecular confirmation of the parental origin allows to predict the risk of complications, such as gestational trophoblastic neoplasia, hyperthyroidism, hypertension, or preeclampsia associated with the paternal origin of triploidy. Diagnosis of partial hydatidiform mole associated with diandric triploidy is challenging especially in the first trimester pregnancy loss due to the limitations of both histopathology and ultrasound. We present important clinical aspects of triploid pregnancies and indicate unresolved issues demanding further studies.

Twin pregnancies discordant for digynic triploidy - A case series.

OBJECTIVE: To analyse natural course and perinatal management in twin pregnancies discordant for digynic triploidy. CASE REPORT: We present five cases of twins discordant for digynic triploidy. Pregnancy outcome was known for three of them. In one case, premature rupture of membranes occurred at 20 gestational weeks and both fetuses were miscarried. In two other pregnancies healthy co-twins were born at term after the triploid fetuses demise at 28 and 37 weeks. No maternal complications were observed. CONCLUSION: Twin pregnancies discordant for triploidy poses a challenge for perinatal management. Expectant management should be considered in digynic triploid cases.

Usefulness of methylation-specific multiplex ligation-dependent probe amplification for identification of parental origin of triploidy.

Triploidy is a genetic aberration resulting from an extra haploid set of chromosomes of paternal (diandric) or maternal (digynic) origin. Diandric cases, opposite to digynic ones, may lead to gestational trophoblastic neoplasia (GTN) or generate maternal complications, therefore their identification is crucial, but reproducibility of traditionally used histopathological assessment is poor. The aim of the study was to analyse the usefulness of methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) with probes for two differentially methylated regions (DMR) at chromosome 11p.15.5 for identification of the parental origin of triploidy. 84 triploid DNA samples were tested with MS-MLPA: 34 paternal cases (40.5%) and 50 maternal ones (59.5%) according to the reference results of QF-PCR. Methylation ratio (MR) was calculated. Reference values proposed by the MRC-Holland for diploid samples (MR 0.8-1.2) were used. The values outside these ranges were used to diagnose parental origin of triploidy-paternal (MR > 1.2) or maternal (MR < 0.8). The effectiveness of MS-MLPA was 94.0%. The mean MR in paternal triploidy was 1.7 (SD-0.25; n = 34) compared with 0.56 in maternal triploidy (SD-0.12; n = 50). MR values in paternal and maternal triploidy did not overlap. In five samples (6.0%) parental origin of triploidy could not be accurately established by MS-MLPA, probably due to the maternal cell contamination (MCC). MS-MLPA can be used as a convenient method for distinguishing between paternal and maternal triploidy without the necessity for parental samples testing. It enables adequate selection of the paternal triploid cases for follow up in order to exclude post-molar GTN.

Prenatal diagnosis of Duchenne and Becker muscular dystrophies: Underestimated problem of the secondary prevention of monogenetic disorders.

AIM: The aim of this study was to analyze the influence of effective preconceptional testing for carrier status in women at risk for Duchenne and Becker muscular dystrophies (D/BMD) on the prenatal diagnosis. METHODS: A retrospective analysis of 201 prenatal tests was performed in 169 Polish women at risk, in regard to time of testing for carrier status (prior to conception or during pregnancy) and carrier status of tested women, including confirmed D/BMD carriers (n = 78; 46.2%), D/BMD non-carriers - tested for germline mosaicism risk (n = 23; 13.6%), and women at risk with uncertain carrier status (n = 68; 40.2%). RESULTS: Only 52.7% of women were tested for D/BMD carrier status prior to conception and in these women prenatal diagnosis was carried out more frequently in the first trimester of pregnancy (64.7% vs 47.8%; P = 0.035). The results of prenatal testing in male fetuses in pregnancies of confirmed D/BMD carriers and D/BMD non-carriers - tested for germline mosaicism risk were conclusive in all cases, whereas in women with uncertain carrier status, only 60.0% of results were conclusive. Eighty-five of 103 female fetuses (82.5%) were tested prenatally and in 31.8% of them fetal carrier status was confirmed. CONCLUSION: Carrier status testing in women prior to conception has a positive impact on the frequency of first-trimester prenatal diagnosis and known D/BMD carrier status on the effectiveness of prenatal diagnosis. Due to the low percentage of women tested effectively prior to conception, carrier status testing in the families at risk should be propagated (including possibility of prenatal diagnosis of female fetuses).

First trimester pregnancy loss: Clinical implications of genetic testing.

Around 10-15% of pregnancies result in a spontaneous first trimester miscarriage, which is most frequently caused by chromosomal abnormalities, mainly aneuploidies. Genetic analysis of pregnancy loss includes conventional G-banding karyotyping and various molecular methods. Apart from variable methodological limitations, the effectiveness of genetic analysis depends on the type and quality of the tested sample. To improve the reliability of genetic testing, we present methods of appropriate collection and pre-laboratory preparation of chorionic villi from first trimester miscarriage. We also discuss issues of maternal cell contamination, placental mosaicism and reciprocal and Robertsonian translocations in the context of interpretation of the results and genetic counseling.

Impaired social cognition processes in Asperger syndrome and anorexia nervosa. In search for endophenotypes of social cognition. / Zaburzenia procesów spolecznego poznania w zespole Aspergera i jadlowstrecie psychicznym. W poszukiwaniu endofenotypów spolecznego poznania.

A growing number of publications indicates presence of significant deficits in social cognition in patients with anorexia nervosa (AN). These deficits appear to be comparable in qualitative and quantitative dimension with impairment of the same functions among people with Asperger syndrome (AS). The aim of this study is to identify subject areas in the field of impairment of social cognition processes among people with Asperger syndrome and anorexia nervosa taking into consideration the potential contribution of genetic pathways of oxytocin and vasopressin in the pathogenesis of these diseases. In the first part of the paper a systematic analysis of studies aimed at the evaluation of the processes of social cognition among patients with AN and AS has been carried out. The results of a significant number of studies confirm the presence of deficits in social cognition in AN and AS. In addition, among patients with AN and AS there exists a similar structure and distribution of the brain functions in regions responsible for social cognition. The second part of the paper describes the role of the oxytocin-vasopressin system (OT-AVP) in the processes of social cognition in AN and AS. Its genetic basis and the possible importance of single nucleotide polymorphisms within the genes: OXT, AVP, CD38, OXTR, AVPR1A and LNPEP have also been presented.