Prenatal exome sequencing analysis in fetal structural anomalies detected by ultrasonography (PAGE): a cohort study.

BACKGROUND: Fetal structural anomalies, which are detected by ultrasonography, have a range of genetic causes, including chromosomal aneuploidy, copy number variations (CNVs; which are detectable by chromosomal microarrays), and pathogenic sequence variants in developmental genes. Testing for aneuploidy and CNVs is routine during the investigation of fetal structural anomalies, but there is little information on the clinical usefulness of genome-wide next-generation sequencing in the prenatal setting. We therefore aimed to evaluate the proportion of fetuses with structural abnormalities that had identifiable variants in genes associated with developmental disorders when assessed with whole-exome sequencing (WES). METHODS: In this prospective cohort study, two groups in Birmingham and London recruited patients from 34 fetal medicine units in England and Scotland. We used whole-exome sequencing (WES) to evaluate the presence of genetic variants in developmental disorder genes (diagnostic genetic variants) in a cohort of fetuses with structural anomalies and samples from their parents, after exclusion of aneuploidy and large CNVs. Women were eligible for inclusion if they were undergoing invasive testing for identified nuchal translucency or structural anomalies in their fetus, as detected by ultrasound after 11 weeks of gestation. The partners of these women also had to consent to participate. Sequencing results were interpreted with a targeted virtual gene panel for developmental disorders that comprised 1628 genes. Genetic results related to fetal structural anomaly phenotypes were then validated and reported postnatally. The primary endpoint, which was assessed in all fetuses, was the detection of diagnostic genetic variants considered to have caused the fetal developmental anomaly. FINDINGS: The cohort was recruited between Oct 22, 2014, and June 29, 2017, and clinical data were collected until March 31, 2018. After exclusion of fetuses with aneuploidy and CNVs, 610 fetuses with structural anomalies and 1202 matched parental samples (analysed as 596 fetus-parental trios, including two sets of twins, and 14 fetus-parent dyads) were analysed by WES. After bioinformatic filtering and prioritisation according to allele frequency and effect on protein and inheritance pattern, 321 genetic variants (representing 255 potential diagnoses) were selected as potentially pathogenic genetic variants (diagnostic genetic variants), and these variants were reviewed by a multidisciplinary clinical review panel. A diagnostic genetic variant was identified in 52 (8·5%; 95% CI 6·4-11·0) of 610 fetuses assessed and an additional 24 (3·9%) fetuses had a variant of uncertain significance that had potential clinical usefulness. Detection of diagnostic genetic variants enabled us to distinguish between syndromic and non-syndromic fetal anomalies (eg, congenital heart disease only vs a syndrome with congenital heart disease and learning disability). Diagnostic genetic variants were present in 22 (15·4%) of 143 fetuses with multisystem anomalies (ie, more than one fetal structural anomaly), nine (11·1%) of 81 fetuses with cardiac anomalies, and ten (15·4%) of 65 fetuses with skeletal anomalies; these phenotypes were most commonly associated with diagnostic variants. However, diagnostic genetic variants were least common in fetuses with isolated increased nuchal translucency (≥4·0 mm) in the first trimester (in three [3·2%] of 93 fetuses). INTERPRETATION: WES facilitates genetic diagnosis of fetal structural anomalies, which enables more accurate predictions of fetal prognosis and risk of recurrence in future pregnancies. However, the overall detection of diagnostic genetic variants in a prospectively ascertained cohort with a broad range of fetal structural anomalies is lower than that suggested by previous smaller-scale studies of fewer phenotypes. WES improved the identification of genetic disorders in fetuses with structural abnormalities; however, before clinical implementation, careful consideration should be given to case selection to maximise clinical usefulness. FUNDING: UK Department of Health and Social Care and The Wellcome Trust.

Diagnosis of primary cerebral lymphomas: possible value of PCR testing in equivocal cases requiring rebiopsy.

INTRODUCTION. Rebiopsy rates as high as 12% have been reported in previous studies of Primary Central Nervous System Lymphoma (PCNSL). This can lead to secondary operations, increasing risks of morbidity to the patient and costs for the NHS. Polymerase Chain Reaction (PCR) testing for clonality in haematological malignancies has been applied to cases of lymphoma outwith the central nervous system (CNS), but is less commonly used in the diagnosis of CNS lymphomas. Clonality in B- and T-cell populations may indicate the presence of malignancy. We aimed to identify factors to reduce the rebiopsy rate in PCNSL. METHODS. We examined a cohort of 102 suspected cerebral lymphoma cases biopsied at Frenchay Hospital, Bristol over a 10-year period (2000-2010). Clinical data, including age, sex, location, pre-biopsy steroid use, the need for rebiopsy and histological diagnosis, were collected. We retrospectively reviewed rebiopsied cases and they subsequently underwent PCR testing for clonality. RESULTS. Overall, 96/102 (94%) cases achieved a histological diagnosis after one or more biopsies. 81/96 (84%) of these were lymphomas involving the brain and 15/96 (16%) were spinal lymphomas. The majority of these were B-cell lymphomas (95/96 (99%)), with one case of peripheral T-cell lymphoma (1/96 (1%)). Due to insufficient histological evidence of PCNSL after the first biopsy, 9/102 (9%) of cases had required rebiopsy. In 7/9 (78%) of these cases, we undertook PCR testing for clonality on tissue from the first biopsy. We found 3/7 (43%) cases were monoclonal for B or T populations, raising the possibility of PCNSL. CONCLUSIONS. We recommend that all CNS lymphoproliferative lesions be assessed by haematopathologists, with the inclusion of PCR testing particularly in equivocal cases. This would reduce the number of patients going for rebiopsy and reduce the patient morbidity and costs for the NHS.

Exchange programmes and student mobility: meeting student's expectations or an expensive holiday?

The Bologna Process aims, amongst other things, to improve the mobility of Students within the EU. Student mobility is supported through programmes such as ERASMUS, and the success of these programmes is measured against quality and quantity of Student mobility within the European Union. This study aimed at establishing, from the students' perspective, the benefits of these programmes. To this purpose, 7 Students who were involved in a German-Finnish exchange programme were interviewed. This population was chosen, because they represented the largest group of students going to the same host university, and were influenced by the same variables, such as language difficulties and climatic conditions. The main objective of this study was to determine whether the educational and personal needs of the students were met during their exchange programme. The data analysis was done using Mayring's content analysis method. The results showed that successful mobility at student level, could lead to a diffusion of knowledge and skills between different countries. It was also found that the students indicated that their personal and educational needs were met irrespective of the language difficulties they experienced.

A further case of confined placental mosaicism for trisomy 2 associated with adverse pregnancy outcome.

OBJECTIVES: To add to the knowledge base concerning confined placental mosaicism for trisomy 2. METHODS: Cytogenetic study of a late CVS referred for hyperechogenic bowel and raised AFP, and cytogenetic and molecular genetic study of a follow-up amniocentesis. Ultrasound monitoring at regular intervals following the CVS result. RESULTS: All cells examined from direct and cultured CVS showed a 47,XY,+2 karyotype. Amniocentesis showed a mosaic 47,XY,+2[8]/46,XY[81] karyotype. Uniparental disomy (UPD) studies on the amniotic fluid showed normal biparental inheritance. The pregnancy developed oligohydramnios and IUGR and resulted in a 26-week liveborn male infant with a 46,XY karyotype, which died after 3 days because of complications of severe prematurity. Placental villi post delivery showed only the 47,XY,+2 cell line. CONCLUSIONS: This case represents a further example of confined placental mosaicism (CPM) for trisomy 2 associated with oligohydramnios, IUGR and poor pregnancy outcome.