Preconceptional genetic carrier testing and the commercial offer directly-to-consumers

Recently, a number of commercial companies are offering preconceptional carrier tests directly-to-consumers. This offer raises a number of concerns and issues above and beyond those encountered with preconceptional tests offered within the traditional health care setting. In order to bring some of these issues to light and to initiate dialogue on this topic, this article discusses the following issues: the current offer of preconceptional carrier tests (until the end of 2010) through online commercial companies; the implications for the informed consent procedure and the need for good information; the need for medical supervision and follow-up; and the appropriate use of existing resources. The article concludes with some reflections about the potential sustainability of the offer of preconceptional carrier tests directly-to-consumers

Views of patients and parents of children with genetic disorders on population-based expanded carrier screening

Objective Faster and cheaper next generation sequencing technologies have enabled expansion of carrier screening for recessive disorders, potentially facilitating population-based implementation regardless of ancestry or family history. Little is known, however, about the attitudes regarding population-based carrier screening among families with genetic disorders. This study assessed views among parents and patients with a recessive disorder and parents of children with Down syndrome (DS) on expanded carrier screening (ECS). Method In total, 85 patients with various recessive disorders, 110 parents of a child with a recessive disorder and 89 parents of a child with DS participated in an online survey in the Netherlands. Severity of recessive disorders was classified as mild/moderate or severe/profound. Results The majority of the (parents of) patients with a recessive disorder had a positive attitude towards population-based ECS, including screening for their own or their child's disorder. DS parents were significantly less positive towards ECS. Subgroup analyses showed that the severity of the disorder, rather than being a patient or parent, influences the attitudes, beliefs and intention to participate in ECS. Conclusion Our findings have important implications for future implementation initiatives as they demonstrate the different perspectives from people with experiential knowledge with genetic disorders

Tracheal agenesis: approach towards this severe diagnosis. Case report and review of the literature

Tracheal agenesis (TA) is a severe congenital disorder with often an unexpected emergency presentation. There is complete or partial absence of the trachea below the larynx, with presence or absence of a tracheoesophageal fistula (TOF). A neonate with TA is described, and another 48 cases found in literature are reviewed. Due to absence of a TOF, five cases were diagnosed prenatally because of congenital high airway obstruction syndrome (CHAOS). When a TOF is present, polyhydramnion and several other congenital malformations seen on the ultrasound examination should alert clinicians of potential tracheal problems. Prenatal magnetic resonance imaging (MRI) may provide a definitive diagnosis. Postnatal diagnosis is based on recognition of specific clinical signs in the newborn with TA: respiratory distress with breathing movement without appropriate air entry, no audible cry, and failed endotracheal intubation. Despite progress in surgical interventions, mortality remains high. Prenatal diagnosis of TA is possible, but only if a TOF is absent resulting in CHAOS. Prenatal diagnosis of polyhydramnion and other congenital malformation should alert clinicians of potential tracheal problems. Prenatal MRI may provide a definitive diagnosis

Responsible implementation of expanded carrier screening.

This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines.European Journal of Human Genetics advance online publication, 16 March 2016; doi:10.1038/ejhg.2015.271

Legius Syndrome in Fourteen Families

Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported. Since only a limited number of patients has been reported up until now, the full clinical and mutational spectrum is still unknown. We report mutation data and clinical details in fourteen new families with Legius syndrome. Six novel germline mutations are described. The Trp31Cys mutation is a new pathogenic SPRED1 missense mutation. Clinical details in the 14 families confirmed the absence of neurofibromas, and Lisch nodules, and the absence of a high prevalence of central nervous system tumors. We report white matter T2 hyperintensities on brain MRI scans in 2 patients and a potential association between postaxial polydactyly and Legius syndrome. © 2010 Wiley-Liss, Inc

Fetal akinesia deformation sequence and massive perivillous fibrin deposition resulting in fetal death in six fetuses from one consanguineous couple, including literature review

Background: Massive perivillous fibrin deposition (MPFD) is associated with adverse pregnancy outcomes and is mainly caused by maternal factors with limited involvement of fetal or genetic causes. We present one consanguineous couple with six fetuses developing Fetal Akinesia Deformation Sequence (FADS) and MPFD, with a possible underlying genetic cause. This prompted a literature review on prevalence of FADS and MPFD. Methods: Fetal ultrasound examination, motor assessment, genetic testing, postmortem examination, and placenta histology are presented (2009–2019). Literature was reviewed for the association between congenital anomalies and MPFD. Results: All six fetuses developed normally during the first trimester. Thereafter, growth restriction, persistent flexed position, abnormal motility, and contractures in 4/6, consistent with FADS occurred. All placentas showed histologically confirmed MPFD. Genetic analyses in the five available cases showed homozygosity for two variants of unknown significance in two genes, VARS1 (OMIM*192150) and ABCF1 (OMIM*603429). Both parents are heterozygous for these variants. From 63/1999 manuscripts, 403 fetal outcomes were mobilized. In 14/403 fetuses, congenital abnormalities in association with MPFD were seen of which two fetuses with contractures/FADS facial anomalies. Conclusion: The low prevalence of fetal contractures/FADS facial anomalies in association with MPFD in the literature review supports the possible fetal or genetic contribution causing FADS and MPFD in our family. This study with literature review supports the finding that fetal, fetoplacental, and/or genetic components may play a role in causing a part of MPFDs

The detection of a strong episignature for Chung–Jansen syndrome, partially overlapping with Börjeson–Forssman–Lehmann and White–Kernohan syndromes

Chung-Jansen syndrome is a neurodevelopmental disorder characterized by intellectual disability, behavioral problems, obesity and dysmorphic features. It is caused by pathogenic variants in the PHIP gene that encodes for the Pleckstrin homology domain-interacting protein, which is part of an epigenetic modifier protein complex. Therefore, we hypothesized that PHIP haploinsufficiency may impact genome-wide DNA methylation (DNAm). We assessed the DNAm profiles of affected individuals with pathogenic and likely pathogenic PHIP variants with Infinium Methylation EPIC arrays and report a specific and sensitive DNAm episignature biomarker for Chung–Jansen syndrome. In addition, we observed similarities between the methylation profile of Chung–Jansen syndrome and that of functionally related and clinically partially overlapping genetic disorders, White–Kernohan syndrome (caused by variants in DDB1 gene) and Börjeson–Forssman–Lehmann syndrome (caused by variants in PHF6 gene). Based on these observations we also proceeded to develop a common episignature biomarker for these disorders. These newly defined episignatures can be used as part of a multiclass episignature classifier for screening of affected individuals with rare disorders and interpretation of genetic variants of unknown clinical significance, and provide further insights into the common molecular pathophysiology of the clinically-related Chung–Jansen, Börjeson–Forssman–Lehmann and White–Kernohan syndromes.</p

The detection of a strong episignature for Chung-Jansen syndrome, partially overlapping with Börjeson-Forssman-Lehmann and White-Kernohan syndromes

Chung-Jansen syndrome is a neurodevelopmental disorder characterized by intellectual disability, behavioral problems, obesity and dysmorphic features. It is caused by pathogenic variants in the PHIP gene that encodes for the Pleckstrin homology domain-interacting protein, which is part of an epigenetic modifier protein complex. Therefore, we hypothesized that PHIP haploinsufficiency may impact genome-wide DNA methylation (DNAm). We assessed the DNAm profiles of affected individuals with pathogenic and likely pathogenic PHIP variants with Infinium Methylation EPIC arrays and report a specific and sensitive DNAm episignature biomarker for Chung-Jansen syndrome. In addition, we observed similarities between the methylation profile of Chung-Jansen syndrome and that of functionally related and clinically partially overlapping genetic disorders, White-Kernohan syndrome (caused by variants in DDB1 gene) and Börjeson-Forssman-Lehmann syndrome (caused by variants in PHF6 gene). Based on these observations we also proceeded to develop a common episignature biomarker for these disorders. These newly defined episignatures can be used as part of a multiclass episignature classifier for screening of affected individuals with rare disorders and interpretation of genetic variants of unknown clinical significance, and provide further insights into the common molecular pathophysiology of the clinically-related Chung-Jansen, Börjeson-Forssman-Lehmann and White-Kernohan syndromes