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QC 20190731

The incidence of stillbirth in Sweden has essentially remained constant since the 1980s, and despite thorough investigation, many cases remain unexplained. It has been suggested that a proportion of stillbirth cases is caused by heart disease, mainly channelopathies. The aim of this study was to analyze DNA from 290 stillbirth cases without chromosomal abnormalities for pathogenic single nucleotide variants (SNVs) in 70 genes associated with cardiac channelopathies and cardiomyopathies. The HaloPlex Target Enrichment System (Agilent Technologies) was utilized to prepare sequencing libraries which were sequenced on the Illumina NextSeq platform. We found that 12.1% of the 290 investigated stillbirth cases had one (n = 31) or two (n = 4) variants with evidence supporting pathogenicity, i.e. loss-of-function variants (nonsense, frameshift, splice site substitutions), evidence from functional studies, or previous identification of the variants in affected individuals. Regarding identified putative pathogenic variants in genes associated with channelopathies, the prevalence was significantly higher in the stillbirth cohort (n = 23, 7.93%) than the corresponding prevalence of the same variants in the non-Finnish European population of the Exome Aggregation Consortium (2.70%, pamp;lt;0.001) and SweGen, (2.30%, pamp;lt;0.001). Our results give further support to the hypothesis that cardiac channelopathies might contribute to stillbirth. Screening for pathogenic SNVs in genes associated with heart disease might be a valuable complement for stillbirth cases where todays conventional investigation does not reveal the underlying cause of fetal demise., Funding Agencies|FORSS, Forskningsradet i sydostra Sverige (the Medical Research Council of Southeast Sweden) [FORSS-307961]; Stockholms Ians landsting (Stockholm County Council) [SLL20160339]

Prenatal diagnosis enables identification of severe disease in the fetus, and allows for planning and management of future pregnancies if an underlying genetic mechanism is identified. The studies included in this thesis have taken advantage of the dramatic progress in medical genetics, in order to develop and evaluate new procedures to diagnose genetic disorders in fetal life. A correct diagnosis is important not only for the management and counseling of the patient or couple, but may also have an impact on the extended family, as there may be undetected carriers. The incidence of stillbirth in Sweden, i.e. fetal death occurring at gestational week ≥22, has essentially remained constant since the 1980’s, and despite thorough investigation, many cases remain unexplained. In Paper I, clinical chromosome analysis results from 481 stillbirth cases were compiled, and a subgroup of 90 cases were analyzed using chromosomal microarray (CMA) to study the potential benefits of the method. The conventional analysis detected chromosomal aberrations in 7.5% of the cases. CMA additionally identified two known syndromes, one disruption of a known disease gene, and 26 variants of unknown significance. Furthermore, CMA had a significantly higher success rate than cytogenetic analysis (100% vs. 80%, p<0.001). As CMA increased both the success rate and diagnosis rate, we concluded that it is a valuable tool in stillbirth investigation. In Paper II, DNA from 290 stillbirth cases was analyzed by massive parallel sequencing of 79 genes associated with heart disease. Sixty-two cases (21.4%) had putative pathogenic variants in genes associated with channelopathies (53%), cardiomyopathies (24%) or congenital heart defects (23%). Screening for pathogenic variants in genes associated with heart disease might be a valuable complement in cases where the conventional investigation does not reveal the underlying cause of fetal demise. Fetal tissue calcifications are occasionally noted during aut

OBJECTIVE: The clinical utilization of non-invasive prenatal testing (NIPT) for identification of fetal aneuploidies is expanding worldwide. The aim of this study was to gain an increased understanding of pregnant women's awareness, attitudes, preferences for risk information and decision-making concerning prenatal examinations with emphasis on NIPT, before its introduction into Swedish healthcare. METHOD: Pregnant women were recruited to fill in a questionnaire, including multiple-choice questions and Likert scales, at nine maternity clinics located in different areas of Stockholm, Sweden. RESULTS: In total, 1,003 women participated in the study (86% consent rate). The vast majority (90.7%) considered examinations aiming to detect fetal abnormalities to be good. Regarding NIPT, 59.8% stated that they had heard about the method previously, yet 74.0% would like to use the test if available. The main factor affecting the women's decision to undergo prenatal chromosomal screening was worry about the baby's health (82.5%), followed by the urge to have as much information as possible about the fetus (54.5%). Most women (79.9%) preferred to receive NIPT information orally. CONCLUSION: The overwhelming majority of a cohort of 1,003 pregnant women considered prenatal examinations good. Moreover, the majority had a positive attitude towards NIPT and would like to use the test if available.

AimSeveral studies have suggested that rare copy number variants (CNVs) are an important genetic contributor to autism spectrum disorders. The aims of the study were to use chromosomal microarray to investigate the presence of rare copy number variants in a population-based cohort of well-characterised young children with autism spectrum disorders and to relate the genetic results to neurodevelopmental profiles and medical conditions. MethodsWe performed chromosomal microarray on samples from 162 children who had been referred to the Stockholm Autism Centre for Young Children in Sweden after being diagnosed with autism spectrum disorder between 20 and 54months of age. ResultsPathogenic aberrations were detected in 8.6% of the children and variants of uncertain significance were present in another 8.6%. CNVs were more frequent in children with congenital malformations or dysmorphic features as well as in the subgroup with intellectual disability. ConclusionOur results support the use of chromosomal microarray methods for the first tier genetic analysis of autism spectrum disorder. However, it is likely in the near future that chromosomal microarray methods will probably be replaced by whole-exome and whole-genome sequencing technologies in clinical genetic testing.

In order to identify genetic causes of VACTERL association (V vertebral defects, A anorectal malformations, C cardiac defects, T tracheoesofageal fistula, E esophageal atresia, R renal anomalies, L limb deformities), we have collected DNA samples from 20 patients diagnosed with VACTERL or with a VACTERL-like phenotype as well as samples from 19 aborted fetal cases with VACTERL. To investigate the importance of gene dose alterations in the genetic etiology of VACTERL association we have performed a systematic analysis of this cohort using a 180K array comparative genomic hybridization (array-CGH) platform. In addition, to further clarify the significance of PCSK5, HOXD13 and CHD7 genes in the VACTERL phenotype, mutation screening has been performed. We identified pathogenic gene dose imbalances in two fetal cases; a hemizygous deletion of the FANCB gene and a (9;18)(p24;q12) unbalanced translocation. In addition, one pathogenic mutation in CHD7 was detected, while no apparent disease-causing mutations were found in HOXD13 or PCSK5. Our study shows that although large gene dose alterations do not seem to be a common cause in VACTERL association, array-CGH is still important in clinical diagnostics to identify disease cause in individual cases.