Functional studies associate novel DUOX2 gene variants detected in heterozygosity to Crohn's disease.

PURPOSE: Crohn's disease is a chronic gastrointestinal inflammatory disease with possible extraintestinal symptoms. There are predisposing genetic factors and even monogenic variants of the disorder. One of the possible genetic factors are variants of the DUOX2 gene. The protein product of the DUOX2 gene is a dual oxidase enzyme producing H2O2 in the bowel. Reduced H2O2 levels impact mucosal homeostasis and contribute to the development of inflammatory bowel disease. Thus far, only 19 patients with IBD with the DUOX2 variants have been described. METHODS: Here we present a case report of an adolescent female diagnosed at eleven years of age with IBD that was subsequently reclassified as Crohn's disease. She was treated with immunosuppressants and biological therapy but experienced additional complications. Her peripheral blood lymphocyte DNA was studied using massive parallel sequencing. Detected variants were functionally studied. RESULTS: Whole exome sequencing found two novel DUOX2 gene variants: a de novo variant c.3646C>T; p.R1216W and a maternally inherited variant c.3391G>A; p.A1131T which were initially classified as variants of unknown significance. However, follow-up functional studies demonstrated that both DUOX2 variants led to impaired H2O2 generation, which led to their reclassification to the likely pathogenic class according to the ACMG.net. Therefore, we conclude that these variants are causative for the disease. CONCLUSIONS: Identifying novel variants in patients with Crohn's disease and their families is important for precision medicine approaches and understanding of the pathogenesis of likely "monogenic" rare forms of inflammatory bowel disease.

Lessons from two series by physicians and caregivers' self-reported data in DDX3X-related disorders.

INTRODUCTION AND METHODS: We report two series of individuals with DDX3X variations, one (48 individuals) from physicians and one (44 individuals) from caregivers. RESULTS: These two series include several symptoms in common, with fairly similar distribution, which suggests that caregivers' data are close to physicians' data. For example, both series identified early childhood symptoms that were not previously described: feeding difficulties, mean walking age, and age at first words. DISCUSSION: Each of the two datasets provides complementary knowledge. We confirmed that symptoms are similar to those in the literature and provides more details on feeding difficulties. Caregivers considered that the symptom attention-deficit/hyperactivity disorder were most worrisome. Both series also reported sleep disturbance. Recently, anxiety has been reported in individuals with DDX3X variants. We strongly suggest that attention-deficit/hyperactivity disorder, anxiety, and sleep disorders need to be treated.

A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing.

PURPOSE: Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the "ClinVar low-hanging fruit" reanalysis, reasons for the failure of previous analyses, and lessons learned. METHODS: Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. RESULTS: We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). CONCLUSION: The "ClinVar low-hanging fruit" analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock.

Co-designing models for the communication of genomic results for rare diseases: a comparative study in the Czech Republic and the United Kingdom.

The communication of genomic results to patients and families with rare diseases raise distinctive challenges. However, there is little evidence about optimal methods to communicate results to this group of service users. To address this gap, we worked with rare disease families and health professionals from two genetic/genomic services, one in the United Kingdom and one in the Czech Republic, to co-design that best meet their needs. Using the participatory methodology of Experience-Based Co-Design (EBCD), we conducted observations of clinical appointments (n=49) and interviews with family participants (n=23) and health professionals (n=22) to gather their experience of sharing/receiving results. The findings informed a facilitated co-design process, comprising 3 feedback events at each site and a series of meetings and remote consultations. Participants identified a total of four areas of current service models in need of improvement, and co-designed six prototypes of quality improvement interventions. The main finding was the identification of post-test care as the shared priority for improvement for both health professionals and families at the two sites. Our findings indicate the need to strengthen the link between diagnostics (whether or not a pathogenic variant is found) and post-test care, including psychosocial and community support. This raises implications for the reconfigurations of genomic service models, the redefinition of professional roles and responsibilities and the involvement of rare disease patients and families in health care research.

Zimmermann-Laband syndrome in monozygotic twins with a mild neurobehavioral phenotype lacking gingival overgrowth-A case report of a novel KCNN3 gene variant.

Zimmermann-Laband syndrome is a rare, heterogeneous disorder characterized by gingival hypertrophy or fibromatosis, aplastic/hypoplastic nails, hypoplasia of the distal phalanges, hypertrichosis, various degrees of intellectual disability, and distinctive facial features. Three genes are considered causative for ZLS: KCNH1, KCNN3, and ATP6V1B2. We report on a pair of female concordant monozygotic twins, both carrying a novel pathogenic variant in the KCNN3 gene, identified using exome sequencing. Only six ZLS patients with the KCNN3 pathogenic variant have been reported so far. The twins show facial dysmorphism, hypoplastic distal phalanges, aplasia or hypoplasia of nails, and hypertrichosis. During infancy, they showed mild developmental delays, mainly speech. They successfully completed secondary school education and are socio-economically independent. Gingival overgrowth is absent in both individuals. Our patients exhibited an unusually mild phenotype compared to published cases, which is an important diagnostic finding for proper genetic counseling for Zimmermann-Laband syndrome patients and their families.

The clinical significance of A2ML1 variants in Noonan syndrome has to be reconsidered.

The RASopathies are a group of clinically and genetically heterogeneous developmental disorders caused by dysregulation of the RAS/MAPK signalling pathway. Variants in several components and regulators of this pathway have been identified as the pathogenetic cause. In 2015, missense variants in A2ML1 were reported in three unrelated families with clinical diagnosis of Noonan syndrome (NS) and a zebrafish model was presented showing heart and craniofacial defects similar to those caused by a NS-associated Shp2 variant. However, a causal role of A2ML1 variants in NS has not been confirmed since. Herein, we report on 15 individuals who underwent screening of RASopathy-associated genes and were found to carry rare variants in A2ML1, including variants previously proposed to be causative for NS. In cases where parental DNA was available, the respective A2ML1 variant was found to be inherited from an unaffected parent. Seven index patients carrying an A2ML1 variant presented with an alternate disease-causing genetic aberration. These findings underscore that current evidence is insufficient to support a causal relation between variants in A2ML1 and NS, questioning the inclusion of A2ML1 screening in diagnostic RASopathy testing.

Author Correction: Large-scale targeted sequencing identifies risk genes for neurodevelopmental disorders.

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

Large-scale targeted sequencing identifies risk genes for neurodevelopmental disorders.

Most genes associated with neurodevelopmental disorders (NDDs) were identified with an excess of de novo mutations (DNMs) but the significance in case-control mutation burden analysis is unestablished. Here, we sequence 63 genes in 16,294 NDD cases and an additional 62 genes in 6,211 NDD cases. By combining these with published data, we assess a total of 125 genes in over 16,000 NDD cases and compare the mutation burden to nonpsychiatric controls from ExAC. We identify 48 genes (25 newly reported) showing significant burden of ultra-rare (MAF < 0.01%) gene-disruptive mutations (FDR 5%), six of which reach family-wise error rate (FWER) significance (p < 1.25E-06). Among these 125 targeted genes, we also reevaluate DNM excess in 17,426 NDD trios with 6,499 new autism trios. We identify 90 genes enriched for DNMs (FDR 5%; e.g., GABRG2 and UIMC1); of which, 61 reach FWER significance (p < 3.64E-07; e.g., CASZ1). In addition to doubling the number of patients for many NDD risk genes, we present phenotype-genotype correlations for seven risk genes (CTCF, HNRNPU, KCNQ3, ZBTB18, TCF12, SPEN, and LEO1) based on this large-scale targeted sequencing effort.

De novo SMARCA2 variants clustered outside the helicase domain cause a new recognizable syndrome with intellectual disability and blepharophimosis distinct from Nicolaides-Baraitser syndrome.

PURPOSE: Nontruncating variants in SMARCA2, encoding a catalytic subunit of SWI/SNF chromatin remodeling complex, cause Nicolaides-Baraitser syndrome (NCBRS), a condition with intellectual disability and multiple congenital anomalies. Other disorders due to SMARCA2 are unknown. METHODS: By next-generation sequencing, we identified candidate variants in SMARCA2 in 20 individuals from 18 families with a syndromic neurodevelopmental disorder not consistent with NCBRS. To stratify variant interpretation, we functionally analyzed SMARCA2 variants in yeasts and performed transcriptomic and genome methylation analyses on blood leukocytes. RESULTS: Of 20 individuals, 14 showed a recognizable phenotype with recurrent features including epicanthal folds, blepharophimosis, and downturned nasal tip along with variable degree of intellectual disability (or blepharophimosis intellectual disability syndrome [BIS]). In contrast to most NCBRS variants, all SMARCA2 variants associated with BIS are localized outside the helicase domains. Yeast phenotype assays differentiated NCBRS from non-NCBRS SMARCA2 variants. Transcriptomic and DNA methylation signatures differentiated NCBRS from BIS and those with nonspecific phenotype. In the remaining six individuals with nonspecific dysmorphic features, clinical and molecular data did not permit variant reclassification. CONCLUSION: We identified a novel recognizable syndrome named BIS associated with clustered de novo SMARCA2 variants outside the helicase domains, phenotypically and molecularly distinct from NCBRS.

Expanding the phenotype spectrum associated with pathogenic variants in the COL2A1 and COL11A1 genes.

We report the clinical findings of 26 individuals from 16 unrelated families carrying variants in the COL2A1 or COL11A1 genes. Using Sanger and next-generation sequencing, 11 different COL2A1 variants (seven novel), were identified in 13 families (19 affected individuals), all diagnosed with Stickler syndrome (STL) type 1. In nine families, the COL2A1 disease-causing variant arose de novo. Phenotypically, we observed myopia (95%) and retinal detachment (47%), joint hyperflexibility (92%), midface retrusion (84%), cleft palate (53%), and various degrees of hearing impairment (50%). One patient had a splenic artery aneurysm. One affected individual carrying pathogenic variant in COL2A1 showed no ocular signs including no evidence of membranous vitreous anomaly. In three families (seven affected individuals), three novel COL11A1 variants were found. The propositus with a de novo variant showed an ultrarare Marshall/STL overlap. In the second family, the only common clinical sign was postlingual progressive sensorineural hearing impairment (DFNA37). Affected individuals from the third family had typical STL2 signs. The spectrum of disease phenotypes associated with COL2A1 or COL11A1 variants continues to expand and includes typical STL and various bone dysplasias, but also nonsyndromic hearing impairment, isolated myopia with or without retinal detachment, and STL phenotype without clinically detectable ocular pathology.

The Key Role of Purine Metabolism in the Folate-Dependent Phenotype of Autism Spectrum Disorders: An In Silico Analysis.

Folate deficiency in the critical developmental period has been repeatedly associated with an increased risk of Autism spectrum disorders (ASD), but the key pathophysiological mechanism has not yet been identified. In this work, we focused on identifying genes whose defect has similar consequences to folate depletion in the metabolic network. Within the Flux Balance Analysis (FBA) framework, we developed a method of blocked metabolites that allowed us to define the metabolic consequences of various gene defects and folate depletion. We identified six genes (GART, PFAS, PPAT, PAICS, ATIC, and ADSL) whose blocking results in nearly the same effect in the metabolic network as folate depletion. All of these genes form the purine biosynthetic pathway. We found that, just like folate depletion, the blockade of any of the six genes mentioned above results in a blockage of purine metabolism. We hypothesize that this can lead to decreased adenosine triphosphate (ATP) and subsequently, an S-adenosyl methionine (SAM) pool in neurons in the case of rapid cell division. Based on our results, we consider the methylation defect to be a potential cause of ASD, due to the depletion of purine, and consequently S-adenosyl methionine (SAM), biosynthesis.

Telemedicine strategy of the European Reference Network ITHACA for the diagnosis and management of patients with rare developmental disorders.

BACKGROUND: The European Reference Networks, ERNs, are virtual networks for healthcare providers across Europe to collaborate and share expertise on complex or rare diseases and conditions. As part of the ERNs, the Clinical Patient Management System, CPMS, a secure digital platform, was developed to allow and facilitate web-based, clinical consultations between submitting clinicians and relevant international experts. The European Reference Network on Intellectual Disability, TeleHealth and Congenital Anomalies, ERN ITHACA, was formed to harness the clinical and diagnostic expertise in the sector of rare, multiple anomaly and/or intellectual disability syndromes, chromosome disorders and undiagnosed syndromic disorders. We present the first year results of CPMS use by ERN ITHACA as an example of a telemedicine strategy for the diagnosis and management of patients with rare developmental disorders. RESULTS: ERN ITHACA ranked third in telemedicine activity amongst 24 European networks after 12 months of using the CPMS. Information about 28 very rare cases from 13 different centres across 7 countries was shared on the platform, with diagnostic or other management queries. Early interaction with patient support groups identified data protection as of primary importance in adopting digital platforms for patient diagnosis and care. The first launch of the CPMS was built to accommodate the needs of all ERNs. The ERN ITHACA telemedicine process highlighted a need to customise the CPMS with network-specific requirements. The results of this effort should enhance the CPMS utility for telemedicine services and ERN-specific care outcomes. CONCLUSIONS: We present the results of a long and fruitful process of interaction between the ERN ITHACA network lead team and EU officials, software developers and members of 38 EU clinical genetics centres to organise and coordinate direct e-healthcare through a secure, digital platform. The variability of the queries in just the first 28 cases submitted to the ERN ITHACA CPMS is a fair representation of the complexity and rarity of the patients referred, but also proof of the sophisticated and variable service that could be provided through a structured telemedicine approach for patients and families with rare developmental disorders. Web-based approaches are likely to result in increased accessibility to clinical genomic services.

Assisted Reproductive Techniques and Pregnancy Results in Women with Mayer-Rokitansky-Küster-Hauser Syndrome Undergoing Uterus Transplantation: the Czech Experience.

STUDY OBJECTIVE: This study aimed to evaluate the reproductive potential of patients with Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) who were candidates for uterus transplantation (UTx) before inclusion in the experimental trial, and to summarize the existing experience with posttransplantation embryo transfers in functionally successful cases. DESIGN AND SETTING: A prospective study at a tertiary medical center. PARTICIPANTS: Ten pre-UTx women with MRKHS and 7 successful UTx cases. INTERVENTIONS AND MAIN OUTCOME MEASURES: Ovarian stimulations, frozen embryo collection, embryo transfers, and incidence of pregnancy in MRKHS women in the pre- and posttransplantation periods. RESULTS: The average number of ovarian stimulations to collect the required frozen embryos was 1.9 (1-3). On average, the number of aspirated oocytes was 16.4 (7-38), 12.6 (5-26) oocytes were fertilized, and 7.0 (1-18) embryos were cryopreserved per cycle. To date, the average number of embryo transfers per recipient was 4.9 (3-8), and the embryo transfer/pregnancy rate was 8.8% (3 of 34). Three pregnancies have been achieved to date, including a missed abortion in the 8th week, a birth in the 35th week, and an ongoing pregnancy in the 30th week. CONCLUSIONS: Despite the small number of UTx cases, our data indicated that women with MRKHS showed a good response to ovarian stimulation and blastocyst formation. Although the procedures for fertilization, cryopreservation, and transfer of the embryos were standardized, the success rate per embryo transfer achieved in the study group has been low to date.

Parental gonadal but not somatic mosaicism leading to de novo NFIX variants shared by two brothers with Malan syndrome.

The importance of gonadal mosaicism in families with apparently de novo mutations is being increasingly recognized. We report on two affected brothers initially suggestive of X-linked or autosomal recessive inheritance. Malan syndrome due to shared NFIX variants was diagnosed in the brothers using exome sequencing. The boys shared the same paternal but not maternal haplotype around NFIX, and deep amplicon sequencing showed ~7% of the variant in paternal sperm but not in paternal blood and saliva. We performed review of previous cases of gonadal mosaicism, which suggests that the phenomenon is not uncommon. Gonadal mosaicism is often not accompanied by somatic mosaicism in tissues routinely used for testing, and if both types of mosaicism are present, the frequency of the variant in sperm is often higher than in somatic cells. In families with shared apparently de novo variants without evidence of parental somatic mosaicism, the transmitting parent may be determined through haplotyping of exome variants. Gonadal mosaicism has important consequences for recurrence risks and should be considered in genetic counseling in families with de novo variants.

De Novo Heterozygous POLR2A Variants Cause a Neurodevelopmental Syndrome with Profound Infantile-Onset Hypotonia.

The RNA polymerase II complex (pol II) is responsible for transcription of all ∼21,000 human protein-encoding genes. Here, we describe sixteen individuals harboring de novo heterozygous variants in POLR2A, encoding RPB1, the largest subunit of pol II. An iterative approach combining structural evaluation and mass spectrometry analyses, the use of S. cerevisiae as a model system, and the assessment of cell viability in HeLa cells allowed us to classify eleven variants as probably disease-causing and four variants as possibly disease-causing. The significance of one variant remains unresolved. By quantification of phenotypic severity, we could distinguish mild and severe phenotypic consequences of the disease-causing variants. Missense variants expected to exert only mild structural effects led to a malfunctioning pol II enzyme, thereby inducing a dominant-negative effect on gene transcription. Intriguingly, individuals carrying these variants presented with a severe phenotype dominated by profound infantile-onset hypotonia and developmental delay. Conversely, individuals carrying variants expected to result in complete loss of function, thus reduced levels of functional pol II from the normal allele, exhibited the mildest phenotypes. We conclude that subtle variants that are central in functionally important domains of POLR2A cause a neurodevelopmental syndrome characterized by profound infantile-onset hypotonia and developmental delay through a dominant-negative effect on pol-II-mediated transcription of DNA.

Unique characteristics of informed consent in clinical genetics and genetic counselling.

Rapid development of clinical genetics was enabled by the advances of molecular genetic laboratory diagnostics. Genetic laboratory testing has unique characteristics, and results of germinal genome testing has consequences not only for the patient but also for his relatives. Genetic laboratory testing in the Czech Republic is governed by the act no. 373/2011, which explicitly states that the testing requires the completion of a written informed consent. This article explains in detail the process of obtaining an informed consent within a broader framework of genetic counselling. An informed consent with genetic laboratory testing not only informs the patient (this being its primary purpose), but can also serve as a lead for physicians of other clinical specialties intending to order genetic laboratory tests.

De novo mutations in the GTP/GDP-binding region of RALA, a RAS-like small GTPase, cause intellectual disability and developmental delay.

Mutations that alter signaling of RAS/MAPK-family proteins give rise to a group of Mendelian diseases known as RASopathies. However, among RASopathies, the matrix of genotype-phenotype relationships is still incomplete, in part because there are many RAS-related proteins and in part because the phenotypic consequences may be variable and/or pleiotropic. Here, we describe a cohort of ten cases, drawn from six clinical sites and over 16,000 sequenced probands, with de novo protein-altering variation in RALA, a RAS-like small GTPase. All probands present with speech and motor delays, and most have intellectual disability, low weight, short stature, and facial dysmorphism. The observed rate of de novo RALA variants in affected probands is significantly higher (p = 4.93 x 10(-11)) than expected from the estimated random mutation rate. Further, all de novo variants described here affect residues within the GTP/GDP-binding region of RALA; in fact, six alleles arose at only two codons, Val25 and Lys128. The affected residues are highly conserved across both RAL- and RAS-family genes, are devoid of variation in large human population datasets, and several are homologous to positions at which disease-associated variants have been observed in other GTPase genes. We directly assayed GTP hydrolysis and RALA effector-protein binding of the observed variants, and found that all but one tested variant significantly reduced both activities compared to wild-type. The one exception, S157A, reduced GTP hydrolysis but significantly increased RALA-effector binding, an observation similar to that seen for oncogenic RAS variants. These results show the power of data sharing for the interpretation and analysis of rare variation, expand the spectrum of molecular causes of developmental disability to include RALA, and provide additional insight into the pathogenesis of human disease caused by mutations in small GTPases.

Modeling age-specific facial development in Williams-Beuren-, Noonan-, and 22q11.2 deletion syndromes in cohorts of Czech patients aged 3-18 years: A cross-sectional three-dimensional geometric morphometry analysis of their facial gestalt.

Three-dimensional (3D) virtual facial models facilitate genotype-phenotype correlations and diagnostics in clinical dysmorphology. Within cross-sectional analysis of both genders we evaluated facial features in representative cohorts of Czech patients with Williams-Beuren-(WBS; 12 cases), Noonan-(NS; 14), and 22q11.2 deletion syndromes (22q11.2DS; 20) and compared their age-related developmental trajectories to 21 age, sex and ethnically matched controls in 3-18 years of age. Using geometric morphometry statistically significant differences in facial morphology were found in all cases compared to controls. The dysmorphic features observed in WBS were specific and manifested in majority of cases. During ontogenesis, dysmorphic features associated with increased facial convexity become more pronounced whereas other typical features remained relatively stable. Dysmorphic features observed in NS cases were mostly apparent during childhood and gradually diminished with age. Facial development had a similar progress as in controls, while there has been increased growth of patients' nose and chin in adulthood. Facial characteristics observed in 22q11.2DS, except for hypoplastic alae nasi, did not correspond with the standard description of its facial phenotype because of marked facial heterogeneity of this clinical entity. Because of the sensitivity of 3D facial morphometry we were able to reach statistical significance even in smaller retrospective patient cohorts, which proves its clinical utility within the routine setting.

[Hereditary breast cancer: genetic etiology and current possibilities of prevention and surgical treatment]. / Hereditární formy karcinomu prsu: genetická etiologie a soucasné moznosti prevence a chirurgické lécby.

Cancer is the second most common cause of death in our population just after cardiovascular diseases, since each third individual will become affected by it during their lifetime. Breast cancer is the most common malignancy in women. The lifetime cumulative risk of breast cancer in women under the age of 75 is around 8 % according to Czech statistics. In 70-75 % of all individuals sporadic breast carcinomas are found, with 5-10 % of all women suffer from the hereditary breast and ovarian cancer (HBOC) syndrome. Radical, bilateral, removal of the mammary gland is the most effective prevention of breast cancer in BRCA positive women. We present a summary of 37 BRCA positive Czech patients who underwent prophylactic bilateral mastectomy and whose mean age was 46.5 years. Surgical solution is currently the only effective therapeutic way to prevent breast cancer in BRCA positive women with high genetic risk. The cosmetic consequences of this radical surgery can be solved through many reconstruction tasks.