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.

Perceptions of reproductive healthcare providers regarding their involvement in offering expanded carrier screening in fertility clinics: a qualitative study.

RESEARCH QUESTION: What are the main arguments of reproductive healthcare providers in favour or against their involvement in offering expanded carrier screening (ECS) for recessive disorders at fertility clinics in the Netherlands? DESIGN: Semi-structured interview study with 20 reproductive healthcare providers between May 2020 and January 2021. Participants included 11 gynaecologists, seven fertility doctors, one nurse practitioner and one clinical embryologist, recruited from academic medical centres (n = 13), peripheral facilities associated with academic centres (n = 4), and independent fertility treatment centres (n = 3) in the Netherlands. An interview guide was developed, and thematic content analysis was performed using ATLAS.ti software. RESULTS: Arguments of reproductive healthcare providers in favour of their potential involvement in offering ECS included: (i) opportunities offered by the setting; (ii) motivation to assist in reproduction and prevent suffering; and (iii) to counter unwanted commercialization offers. Arguments against involvement included: (i) lack of knowledge and familiarity with offering ECS; (ii) insufficient staff and resources, and potential high costs for clinics and/or couples; (iii) the emotional impact it may have on couples; (iv) perceived complexity of counselling and expected elongation of waiting lists; and (v) expected low impact on reducing the burden of diseases. Participants felt that more evidence and research on the costs-benefits, implications and demand are needed prior to their involvement. CONCLUSION: While agreeing that the field of medically assisted reproduction provides a unique opportunity to offer ECS, reproductive healthcare workers feel a lack of capability and limited motivation to offer ECS to all or a selection of couples at their fertility clinics.

Medullary Sponge Kidney and Its Relationship with Primary Distal Renal Tubular Acidosis: Case Reports and a Comprehensive Genetics-First Approach.

Medullary sponge kidney (MSK) is a description of radiographic features. However, the pathogenesis of MSK remains unclear. MSK is supposed to be the cause of secondary distal renal tubular acidosis (dRTA), although there are case reports suggesting that MSK is a complication of primary dRTA. In addition to these reports, we report 3 patients with metabolic acidosis and MSK, in whom primary dRTA is confirmed by molecular genetic analyses of SLC4A1 and ATP6V1B1 genes. With a comprehensive genetics-first approach using the 100,000 Genomes Rare Diseases Project dataset, the association between MSK and primary dRTA is examined. We showed that many patients with MSK phenotypes are genetically tested with a gene panel which does not contain dRTA-associated genes, revealing opportunities for missed genetic diagnosis. Our cases highlight that the radiological description of MSK is not a straightforward disease or clinical phenotype. Therefore, when an MSK appearance is noted, a broader set of causes should be considered including genetic causes of primary dRTA as the underlying reason for medullary imaging abnormalities.

Developmental epileptic encephalopathy in DLG4-related synaptopathy.

OBJECTIVE: The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy. METHODS: We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician. RESULTS: A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants. SIGNIFICANCE: Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

Primary care professionals' views on population-based expanded carrier screening: an online focus group study.

BACKGROUND: Population-based expanded carrier screening (ECS) involves screening for multiple recessive diseases offered to all couples considering a pregnancy or during pregnancy. Previous research indicates that in some countries primary care professionals are perceived as suitable providers for ECS. However, little is known about their perspectives. We therefore aimed to explore primary care professionals' views on population-based ECS. METHODS: Four online focus groups with 14 general practitioners (GPs) and 16 community midwives were conducted in the Netherlands. RESULTS: Our findings highlight various perspectives on the desirability of population-based ECS. Participants agreed that ECS could enhance reproductive autonomy and thereby prevent suffering of the child and/or parents. However, they also raised several ethical, societal, and psychological concerns, including a tendency towards a perfect society, stigmatization, unequal access to screening and negative psychosocial consequences. Participants believed that provision of population-based ECS would be feasible if prerequisites regarding training and reimbursement for providers would be fulfilled. most GPs considered themselves less suitable or capable of providing ECS, in contrast to midwives who did consider themselves suitable. Nevertheless, participants believed that, if implemented, ECS should be offered in primary care or by public health services rather than as hospital-based specialized care, because they believed a primary care ECS offer increases access in terms of time and location. CONCLUSIONS: While participants believed that an ECS offer would be feasible, they questioned its desirability and priority. Studies on the desirability and feasibility of population-based ECS offered in primary care or public health settings are needed.

Dynamics of reproductive genetic technologies: Perspectives of professional stakeholders.

Reproductive and genetic medicine are evolving rapidly, and new technologies are already impacting current practices. This includes technologies that can identify a couples' risk of having a child with a genetic disorder. Responsible implementation of new technologies requires evaluation of safety and ethics. Valuable insights for shaping governance processes are provided by various stakeholders involved, including healthcare professionals. Their willingness to adopt these technologies and guide the necessary systemic changes is required for the successful implementation of these technologies. In this study, twenty-one semi-structured interviews were conducted with professionals from different disciplines in the field of reproductive and genetic healthcare in the Netherlands. Three emerging technologies were discussed: expanded carrier screening (ECS), non-invasive prenatal diagnosis (NIPD) and germline genome editing (GGE). By probing stakeholders' views, we explored how culture, structure and practice in healthcare is being shaped by innovations and changing dynamics in genetic and reproductive medicine. The general consensus was that the implementation of reproductive genetic technologies nationwide is a slow process in Dutch healthcare. A "typical Dutch approach" emerged that is characterized by restrictive legislation, broad support for people living with disabilities, values of an egalitarian society and limited commercialisation. Different scenarios for embedding ECS in future practice were envisioned, while implementation of NIPD in clinical practice was considered obvious. Views on GGE varied among stakeholders. Previous implementation examples in the Netherlands suggest introduction of new technology involves an organized collective learning process, with pilot studies and stepwise implementation. In addition, introducing and scaling up new technologies is complex due to perceived barriers from the legislative framework and the complex relationship between the government and stakeholders in this area. This paper describes how the international trends and advances of technologies are expected to manifest itself in a national setting.

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.

Clinical findings and a DNA methylation signature in kindreds with alterations in ZNF711.

ZNF711 is one of eleven zinc-finger genes on the X chromosome that have been associated with X-linked intellectual disability. This association is confirmed by the clinical findings in 20 new cases in addition to 11 cases previously reported. No consistent growth aberrations, craniofacial dysmorphology, malformations or neurologic findings are associated with alterations in ZNF711. The intellectual disability is typically mild and coexisting autism occurs in half of the cases. Carrier females show no manifestations. A ZNF711-specific methylation signature has been identified which can assist in identifying new cases and in confirming the pathogenicity of variants in the gene.

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.

Couples' experiences with expanded carrier screening: evaluation of a university hospital screening offer.

Preconception carrier screening offers couples the possibility to receive information about the risk of having a child with a recessive disorder. Since 2016, an expanded carrier screening (ECS) test for 50 severe autosomal recessive disorders has been available at Amsterdam Medical Center, a Dutch university hospital. This mixed-methods study evaluated the experiences of couples that participated in the carrier screening offer, including high-risk participants, as well as participants with a general population risk. All participants received genetic counselling, and pre- (n = 132) and post-test (n = 86) questionnaires and semi-structured interviews (n = 16) were administered. The most important reason to have ECS was to spare a future child a life with a severe disorder (47%). The majority of survey respondents made an informed decision (86%), as assessed by the Multidimensional Measure of Informed Choice. Among the 86 respondents, 27 individual carriers and no new carrier couples were identified. Turn-around time of the test results was considered too long and costs were perceived as too high. Overall, mean levels of anxiety were not clinically elevated. High-risk respondents (n = 89) and pregnant respondents (n = 13) experienced higher levels of anxiety before testing, which decreased after receiving the test result. Although not clinically significant, distress was on average higher for carriers compared to non-carriers (p < 0.0001). All respondents would opt for the test again, and 80.2% would recommend it to others. The results suggest that ECS should ideally be offered before pregnancy, to minimise anxiety. This study could inform current and future implementation initiatives of preconception ECS.

Preconception expanded carrier screening: a focus group study with relatives of mucopolysaccharidosis type III patients and the general population.

Preconception expanded carrier screening (ECS) enables prospective parents to assess their risk of having a child with an autosomal recessive disorder. Knowledge on motivations, feelings, and considerations people have towards the offer and use of ECS is limited. To enrich the public and professional discussion on ECS implementation, this study explored the perspectives towards various aspects of ECS in seven focus groups compromising first- and second-degree relatives of MPS III patients (N=9, N=4, N=5, N=5) and members of the general Dutch population (N=6, N=7, N=5). The focus groups were audio recorded and the transcripts were qualitatively analyzed to identify themes. Both relatives of MPS III patients and participants from the general population supported offering ECS, in particular for severe, childhood-onset disorders. Important barriers identified for ECS were a lack of genetic knowledge and a perceived lack of personal relevance and awareness, as well as out-of-pocket costs of testing. The majority of participants would prefer full disclosure of individual test results instead of couple-based test results. Moreover, offering people a choice for the way of reporting was proposed. All participants agreed that more efforts, for example by governmental campaigns, should be made to increase awareness on the availability, potentials, and limitations of ECS. Educating prospective parents about ECS is essential for increasing awareness and informed decision making. This study provides valuable insights that can be used by governments and public health authorities when considering implementation of preconception ECS.

Diagnostic exome-based preconception carrier testing in consanguineous couples: results from the first 100 couples in clinical practice.

PURPOSE: Consanguineous couples are at increased risk of being heterozygous for the same autosomal recessive (AR) disorder(s), with a 25% risk of affected offspring as a consequence. Until recently, comprehensive preconception carrier testing (PCT) for AR disorders was unavailable in routine diagnostics. Here we developed and implemented such a test in routine clinical care. METHODS: We performed exome sequencing (ES) for 100 consanguineous couples. For each couple, rare variants that could give rise to biallelic variants in offspring were selected. These variants were subsequently filtered against a gene panel consisting of ~2,000 genes associated with known AR disorders (OMIM-based). Remaining variants were classified according to American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines, after which only likely pathogenic and pathogenic (class IV/V) variants, present in both partners, were reported. RESULTS: In 28 of 100 tested consanguineous couples (28%), likely pathogenic and pathogenic variants not previously known in the couple or their family were reported conferring 25% risk of affected offspring. CONCLUSION: ES-based PCT provides a powerful diagnostic tool to identify AR disease carrier status in consanguineous couples. Outcomes provided significant reproductive choices for a higher proportion of these couples than previous tests.

Phenotypic expansion of the BPTF-related neurodevelopmental disorder with dysmorphic facies and distal limb anomalies.

Neurodevelopmental disorder with dysmorphic facies and distal limb anomalies (NEDDFL), defined primarily by developmental delay/intellectual disability, speech delay, postnatal microcephaly, and dysmorphic features, is a syndrome resulting from heterozygous variants in the dosage-sensitive bromodomain PHD finger chromatin remodeler transcription factor BPTF gene. To date, only 11 individuals with NEDDFL due to de novo BPTF variants have been described. To expand the NEDDFL phenotypic spectrum, we describe the clinical features in 25 novel individuals with 20 distinct, clinically relevant variants in BPTF, including four individuals with inherited changes in BPTF. In addition to the previously described features, individuals in this cohort exhibited mild brain abnormalities, seizures, scoliosis, and a variety of ophthalmologic complications. These results further support the broad and multi-faceted complications due to haploinsufficiency of BPTF.

Preconception expanded carrier screening: Impact of information presented by text or video on genetic knowledge and attitudes.

Preconception expanded carrier screening (ECS) aims to identify couples with an increased risk of having a child with an autosomal recessive (AR) disorder before pregnancy, thereby enabling reproductive choices. Genetic knowledge and experiential knowledge both influence the uptake of ECS. As people in the general public often lack such knowledge, it is essential to provide appropriate and understandable information when offering ECS. This study investigated the effect of an educational video, compared to an educational text, on the knowledge and attitudes toward preconception ECS in the general population. Both the text and video consisted of a brief educational summary on AR inheritance and on the type of disorders included in ECS, with the progressive neurodegenerative condition mucopolysaccharidosis type III (MPS III) as an example. Participants in the reproductive age were invited in collaboration with a research agency. Respondents (N = 789) were offered an educational video prior to completing an online questionnaire that examined genetic knowledge, the perceived severity of MPS III, perceived risk, and attitudes toward ECS. Outcomes were compared to reference data collected previously in which respondents had been offered an educational text (N = 781). We first again studied the attitudes toward ECS in a smaller educational text group (N = 266) in order to assess whether attitudes had changed over time due to increased media coverage on ECS, which did not reveal any significant changes. Respondents who were offered the video had a better genetic knowledge, perceived MPS III as more severe, perceived their risks higher and were more likely to participate in ECS compared to those who were offered text. Online video may well be used as supportive tool to the genetic counseling process, creating more knowledge on ECS and severe genetic disorders included in preconception screening panels.

How will new genetic technologies, such as gene editing, change reproductive decision-making? Views of high-risk couples.

Couples at increased risk of having offspring with a specific genetic disorder who want to avoid having an affected child have several reproductive options including prenatal diagnosis (PND) and preimplantation genetic testing (PGT). In the future, non-invasive prenatal diagnosis (NIPD), germline gene editing (GGE) and somatic gene editing (SGE) might become available. This study explores if, and how, availability of new genetic technologies, including NIPD, GGE, SGE, would change reproductive decision-making of high-risk couples. In 2018, semi-structured interviews were conducted with 25 genetically at-risk couples. Couples previously had received genetic counselling for PND and PGT, and in most cases opted for (one of) these techniques, at one Dutch Clinical Genetics Center between 2013 and 2017. Considerations participants mentioned regarding the hypothetical use of NIPD, GGE and SGE, seem similar to considerations regarding PND and PGT and are reflected in underlying concepts. These include safety and burden for mother and child, and moral considerations. Couples generally favoured NIPD over PND as this would be safe and enables earlier diagnosis. Increased opportunities of having a 'healthy' embryo and less embryo disposal were considerations in favour of GGE. Some regarded GGE as unsafe and feared slippery slope scenarios. Couples were least favourable towards SGE compared to choosing for a genetic reproductive technology, because of the perceived burden for the affected offspring. With the possibly growing number of technological options, understanding high risk couples' perspectives can assist in navigating the reproductive decision-making process. Counsellors should be prepared to counsel on more and complex reproductive options.

Correction: KAT6A Syndrome: genotype-phenotype correlation in 76 patients with pathogenic KAT6A variants.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Attitudes of relatives of mucopolysaccharidosis type III patients toward preconception expanded carrier screening.

Preconception expanded carrier screening (ECS) aims to detect carrier couples of autosomal recessive (AR) disorders before pregnancy in order to increase reproductive autonomy of prospective parents. Genetic knowledge and knowledge gained from experience influence decision making on participation in genetic testing and understanding carrier test results. In this study we assessed whether parents and relatives of patients with the severe AR condition mucopolysaccharidosis type III (MPS III), who are expected to have genetic and experiential knowledge, have more positive attitudes toward ECS than the Dutch reference group. Parents of all MPS III patients known to the Dutch expert center were invited to participate and asked to invite first and second degree relatives. The online questionnaire started with an educational text, and assessed attitudes toward ECS, genetic knowledge and perceived MPS III severity. Results were compared with the Dutch population. Parents and relatives of MPS III patients (n = 159) scored higher on the genetic knowledge test and perceived MPS III as more severe compared with the general Dutch population (n = 781). Parents and relatives reported to be more likely to participate in ECS (84.3% and 62.5%, respectively) compared with the public (31%) (p < 0.001). Being a relative of a MPS III patient was the strongest variable in the regression analyses for intended ECS participation. Our results show that genetic knowledge influences ECS decision making. Therefore, appropriate information on ECS and genetic counseling is needed to enable prospective parents from the general population, including relatives of patients with severe hereditary disorders, to make informed decisions.

A uniparental isodisomy event introducing homozygous pathogenic variants drives a multisystem metabolic disorder.

Uniparental isodisomy (UPiD) is a rare genetic event that occurs when two identical copies of a single chromosome are inherited from one parent. Here we report a patient with a severe, multisystem metabolic disorder who inherited two copies of Chromosome 12 from her father. He was a heterozygous carrier of a variant in the muscle-specific enzyme 6-phosphofructokinase (PFKM) gene and of a truncating variant in the pseudouridine synthase 1 (PUS1) gene (both on Chromosome 12), resulting in a homozygous state of these mutations in his daughter. The PFKM gene functions in glycolysis and is linked to Tarui syndrome. The PUS1 gene functions in mitochondrial tRNA processing and is linked to myopathy, lactic acidosis, and sideroblastic anemia (MLASA). Analysis of human dermal fibroblasts, which do not express PFKM, revealed a loss of PUS1 mRNA and PUS1 protein only in the patient cells compared to healthy controls. The patient cells also revealed a reduction of the mitochondrial-encoded protein MTCO1, whereas levels of the nuclear-encoded SDHA remained unchanged, suggesting a specific impairment of mitochondrial translation. Further destabilization of these cells is suggested by the altered levels of BAX, BCL-2, and TP53 proteins, alterations that become augmented upon exposure of the cells to DNA damage. The results illustrate the efficacy of UPiD events to reveal rare pathogenic variants in human disease and demonstrate how these events can lead to cellular destabilization.