Variants in ZFX are associated with an X-linked neurodevelopmental disorder with recurrent facial gestalt.

Pathogenic variants in multiple genes on the X chromosome have been implicated in syndromic and non-syndromic intellectual disability disorders. ZFX on Xp22.11 encodes a transcription factor that has been linked to diverse processes including oncogenesis and development, but germline variants have not been characterized in association with disease. Here, we present clinical and molecular characterization of 18 individuals with germline ZFX variants. Exome or genome sequencing revealed 11 variants in 18 subjects (14 males and 4 females) from 16 unrelated families. Four missense variants were identified in 11 subjects, with seven truncation variants in the remaining individuals. Clinical findings included developmental delay/intellectual disability, behavioral abnormalities, hypotonia, and congenital anomalies. Overlapping and recurrent facial features were identified in all subjects, including thickening and medial broadening of eyebrows, variations in the shape of the face, external eye abnormalities, smooth and/or long philtrum, and ear abnormalities. Hyperparathyroidism was found in four families with missense variants, and enrichment of different tumor types was observed. In molecular studies, DNA-binding domain variants elicited differential expression of a small set of target genes relative to wild-type ZFX in cultured cells, suggesting a gain or loss of transcriptional activity. Additionally, a zebrafish model of ZFX loss displayed an altered behavioral phenotype, providing additional evidence for the functional significance of ZFX. Our clinical and experimental data support that variants in ZFX are associated with an X-linked intellectual disability syndrome characterized by a recurrent facial gestalt, neurocognitive and behavioral abnormalities, and an increased risk for congenital anomalies and hyperparathyroidism.

Clinical exome sequencing efficacy and phenotypic expansions involving anomalous pulmonary venous return.

Anomalous pulmonary venous return (APVR) frequently occurs with other congenital heart defects (CHDs) or extra-cardiac anomalies. While some genetic causes have been identified, the optimal approach to genetic testing in individuals with APVR remains uncertain, and the etiology of most cases of APVR is unclear. Here, we analyzed molecular data from 49 individuals to determine the diagnostic yield of clinical exome sequencing (ES) for non-isolated APVR. A definitive or probable diagnosis was made for 8 of those individuals yielding a diagnostic efficacy rate of 16.3%. We then analyzed molecular data from 62 individuals with APVR accrued from three databases to identify novel APVR genes. Based on data from this analysis, published case reports, mouse models, and/or similarity to known APVR genes as revealed by a machine learning algorithm, we identified 3 genes-EFTUD2, NAA15, and NKX2-1-for which there is sufficient evidence to support phenotypic expansion to include APVR. We also provide evidence that 3 recurrent copy number variants contribute to the development of APVR: proximal 1q21.1 microdeletions involving RBM8A and PDZK1, recurrent BP1-BP2 15q11.2 deletions, and central 22q11.2 deletions involving CRKL. Our results suggest that ES and chromosomal microarray analysis (or genome sequencing) should be considered for individuals with non-isolated APVR for whom a genetic etiology has not been identified, and that genetic testing to identify an independent genetic etiology of APVR is not warranted in individuals with EFTUD2-, NAA15-, and NKX2-1-related disorders.

Timing of Primary Surgery for Cleft Palate.

BACKGROUND: Among infants with isolated cleft palate, whether primary surgery at 6 months of age is more beneficial than surgery at 12 months of age with respect to speech outcomes, hearing outcomes, dentofacial development, and safety is unknown. METHODS: We randomly assigned infants with nonsyndromic isolated cleft palate, in a 1:1 ratio, to undergo standardized primary surgery at 6 months of age (6-month group) or at 12 months of age (12-month group) for closure of the cleft. Standardized assessments of quality-checked video and audio recordings at 1, 3, and 5 years of age were performed independently by speech and language therapists who were unaware of the trial-group assignments. The primary outcome was velopharyngeal insufficiency at 5 years of age, defined as a velopharyngeal composite summary score of at least 4 (scores range from 0 to 6, with higher scores indicating greater severity). Secondary outcomes included speech development, postoperative complications, hearing sensitivity, dentofacial development, and growth. RESULTS: We randomly assigned 558 infants at 23 centers across Europe and South America to undergo surgery at 6 months of age (281 infants) or at 12 months of age (277 infants). Speech recordings from 235 infants (83.6%) in the 6-month group and 226 (81.6%) in the 12-month group were analyzable. Insufficient velopharyngeal function at 5 years of age was observed in 21 of 235 infants (8.9%) in the 6-month group as compared with 34 of 226 (15.0%) in the 12-month group (risk ratio, 0.59; 95% confidence interval, 0.36 to 0.99; P = 0.04). Postoperative complications were infrequent and similar in the 6-month and 12-month groups. Four serious adverse events were reported (three in the 6-month group and one in the 12-month group) and had resolved at follow-up. CONCLUSIONS: Medically fit infants who underwent primary surgery for isolated cleft palate in adequately resourced settings at 6 months of age were less likely to have velopharyngeal insufficiency at the age of 5 years than those who had surgery at 12 months of age. (Funded by the National Institute of Dental and Craniofacial Research; TOPS ClinicalTrials.gov number, NCT00993551.).

Monotherapy treatment of epilepsy in pregnancy: congenital malformation outcomes in the child.

BACKGROUND: Prenatal exposure to certain anti-seizure medications (ASMs) is associated with an increased risk of major congenital malformations (MCM). The majority of women with epilepsy continue taking ASMs throughout pregnancy and, therefore, information on the potential risks associated with ASM treatment is required. OBJECTIVES: To assess the effects of prenatal exposure to ASMs on the prevalence of MCM in the child. SEARCH METHODS: For the latest update of this review, we searched the following databases on 17 February 2022: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid, 1946 to February 16, 2022), SCOPUS (1823 onwards), and ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP). No language restrictions were imposed. SELECTION CRITERIA: We included prospective cohort controlled studies, cohort studies set within pregnancy registries, randomised controlled trials and epidemiological studies using routine health record data. Participants were women with epilepsy taking ASMs; the two control groups were women without epilepsy and untreated women with epilepsy. DATA COLLECTION AND ANALYSIS: Five authors independently selected studies for inclusion. Eight authors completed data extraction and/or risk of bias assessments. The primary outcome was the presence of an MCM. Secondary outcomes included specific types of MCM. Where meta-analysis was not possible, we reviewed included studies narratively. MAIN RESULTS: From 12,296 abstracts, we reviewed 283 full-text publications which identified 49 studies with 128 publications between them. Data from ASM-exposed pregnancies were more numerous for prospective cohort studies (n = 17,963), than data currently available for epidemiological health record studies (n = 7913). The MCM risk for children of women without epilepsy was 2.1% (95% CI 1.5 to 3.0) in cohort studies and 3.3% (95% CI 1.5 to 7.1) in health record studies. The known risk associated with sodium valproate exposure was clear across comparisons with a pooled prevalence of 9.8% (95% CI 8.1 to 11.9) from cohort data and 9.7% (95% CI 7.1 to 13.4) from routine health record studies. This was elevated across almost all comparisons to other monotherapy ASMs, with the absolute risk differences ranging from 5% to 9%. Multiple studies found that the MCM risk is dose-dependent. Children exposed to carbamazepine had an increased MCM prevalence in both cohort studies (4.7%, 95% CI 3.7 to 5.9) and routine health record studies (4.0%, 95% CI 2.9 to 5.4) which was significantly higher than that for the children born to women without epilepsy for both cohort (RR 2.30, 95% CI 1.47 to 3.59) and routine health record studies (RR 1.14, 95% CI 0.80 to 1.64); with similar significant results in comparison to the children of women with untreated epilepsy for both cohort studies (RR 1.44, 95% CI 1.05 to 1.96) and routine health record studies (RR 1.42, 95% CI 1.10 to 1.83). For phenobarbital exposure, the prevalence was 6.3% (95% CI 4.8 to 8.3) and 8.8% (95% CI 0.0 to 9277.0) from cohort and routine health record data, respectively. This increased risk was significant in comparison to the children of women without epilepsy (RR 3.22, 95% CI 1.84 to 5.65) and those born to women with untreated epilepsy (RR 1.64, 95% CI 0.94 to 2.83) in cohort studies; data from routine health record studies was limited. For phenytoin exposure, the prevalence of MCM was elevated for cohort study data (5.4%, 95% CI 3.6 to 8.1) and routine health record data (6.8%, 95% CI 0.1 to 701.2). The prevalence of MCM was higher for phenytoin-exposed children in comparison to children of women without epilepsy (RR 3.81, 95% CI 1.91 to 7.57) and the children of women with untreated epilepsy (RR 2.01. 95% CI 1.29 to 3.12); there were no data from routine health record studies. Pooled data from cohort studies indicated a significantly increased MCM risk for children exposed to lamotrigine in comparison to children born to women without epilepsy (RR 1.99, 95% CI 1.16 to 3.39); with a risk difference (RD) indicating a 1% increased risk of MCM (RD 0.01. 95% CI 0.00 to 0.03). This was not replicated in the comparison to the children of women with untreated epilepsy (RR 1.04, 95% CI 0.66 to 1.63), which contained the largest group of lamotrigine-exposed children (> 2700). Further, a non-significant difference was also found both in comparison to the children of women without epilepsy (RR 1.19, 95% CI 0.86 to 1.64) and children born to women with untreated epilepsy (RR 1.00, 95% CI 0.79 to 1.28) from routine data studies. For levetiracetam exposure, pooled data provided similar risk ratios to women without epilepsy in cohort (RR 2.20, 95% CI 0.98 to 4.93) and routine health record studies (RR 0.67, 95% CI 0.17 to 2.66). This was supported by the pooled results from both cohort (RR 0.71, 95% CI 0.39 to 1.28) and routine health record studies (RR 0.82, 95% CI 0.39 to 1.71) when comparisons were made to the offspring of women with untreated epilepsy. For topiramate, the prevalence of MCM was 3.9% (95% CI 2.3 to 6.5) from cohort study data and 4.1% (0.0 to 27,050.1) from routine health record studies. Risk ratios were significantly higher for children exposed to topiramate in comparison to the children of women without epilepsy in cohort studies (RR 4.07, 95% CI 1.64 to 10.14) but not in a smaller comparison to the children of women with untreated epilepsy (RR 1.37, 95% CI 0.57 to 3.27); few data are currently available from routine health record studies. Exposure in utero to topiramate was also associated with significantly higher RRs in comparison to other ASMs for oro-facial clefts. Data for all other ASMs were extremely limited. Given the observational designs, all studies were at high risk of certain biases, but the biases observed across primary data collection studies and secondary use of routine health records were different and were, in part, complementary. Biases were balanced across the ASMs investigated, and it is unlikely that the differential results observed across the ASMs are solely explained by these biases. AUTHORS' CONCLUSIONS: Exposure in the womb to certain ASMs was associated with an increased risk of certain MCMs which, for many, is dose-dependent.

ANTECEDENTES: La exposición prenatal a determinados fármacos anticonvulsivos (FAC) se asocia con un mayor riesgo de malformaciones congénitas graves (MCG). La mayoría de las mujeres con epilepsia continúan tomando FAC durante todo el embarazo y, por lo tanto, se requiere información sobre los riesgos potenciales asociados con el tratamiento con FAC. OBJETIVOS: Evaluar los efectos de la exposición prenatal a los FAC sobre la prevalencia de MCG en el niño. MÉTODOS DE BÚSQUEDA: Para la última actualización de esta revisión se hicieron búsquedas el 17 de febrero de 2022 en las siguientes bases de datos: Registro Cochrane de Estudios (Cochrane Register of Studies [CRS Web]), MEDLINE (Ovid, 1946 hasta el 16 de febrero de 2022), SCOPUS (1823 en adelante) y ClinicalTrials.gov , Plataforma de registros internacionales de ensayos clínicos (ICTRP). No se impusieron restricciones de idioma. CRITERIOS DE SELECCIÓN: Se incluyeron estudios prospectivos controlados de cohortes, estudios de cohortes establecidos dentro de registros de embarazos, ensayos controlados aleatorizados y estudios epidemiológicos que utilizaron datos rutinarios de los historiales médicos. Las participantes fueron mujeres con epilepsia que tomaban FAC; los dos grupos de control fueron mujeres sin epilepsia y mujeres con epilepsia que no recibían tratamiento. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Cinco autores seleccionaron de forma independiente los estudios para inclusión. Ocho autores completaron la extracción de los datos y las evaluaciones del riesgo de sesgo. El desenlace principal fue la presencia de una MCG. Los desenlaces secundarios incluyeron tipos específicos de MCG. Cuando no fue posible realizar un metanálisis, los estudios incluidos se examinaron de forma narrativa. RESULTADOS PRINCIPALES: De 12 296 resúmenes, se revisaron 283 publicaciones a texto completo que identificaron 49 estudios con 128 publicaciones entre ellos. Los datos de los embarazos expuestos a FAC fueron más numerosos en el caso de los estudios prospectivos de cohortes (n = 17 963), que los datos actualmente disponibles de estudios de registros sanitarios epidemiológicos (n = 7913). El riesgo de MCG en los hijos de mujeres sin epilepsia fue del 2,1% (IC del 95%: 1,5 a 3,0) en los estudios de cohortes y del 3,3% (IC del 95%: 1,5 a 7,1) en los estudios de registros sanitarios. El riesgo conocido asociado con la exposición al valproato de sodio fue evidente en todas las comparaciones, con una prevalencia agrupada del 9,8% (IC del 95%: 8,1 a 11,9) a partir de los datos de los estudios de cohortes y del 9,7% (IC del 95%: 7,1 a 13,4) a partir de los estudios con datos rutinarios de los historiales médicos. Este fue elevado en casi todas las comparaciones con otros FAC como monoterapia, con diferencias absolutas de riesgo que variaron entre el 5% y el 9%. Múltiples estudios han constatado que el riesgo de MCG depende de la dosis. Los niños expuestos a la carbamazepina tuvieron una mayor prevalencia de MCG tanto en los estudios de cohortes (4,7%; IC del 95%: 3,7 a 5,9) como en los estudios con datos rutinarios de los historiales médicos (4,0%; IC del 95%: 2,9 a 5,4), que fue significativamente superior a la de los niños nacidos de mujeres sin epilepsia tanto en los estudios de cohortes (RR 2,30; IC del 95%: 1,47 a 3,59) como en los estudios de historias clínicas habituales (RR 1,14; IC del 95%: 0,80 a 1,64), con resultados significativos similares en comparación con los hijos de mujeres con epilepsia que no reciben tratamiento tanto en los estudios de cohortes (RR 1,44; IC del 95%: 1,05 a 1,96) como en los estudios con datos rutinarios de los historiales médicos (RR 1,42; IC del 95%: 1,10 a 1,83). Para la exposición al fenobarbital, la prevalencia fue del 6,3% (IC del 95%: 4,8 a 8,3) y del 8,8% IC del 95%: 0,0 a 9277,0) a partir de los datos de estudios de cohortes y los datos de estudios con datos rutinarios de los historiales médicos, respectivamente. Este aumento del riesgo fue significativo en comparación con los hijos de mujeres sin epilepsia (RR 3,22; IC del 95%: 1,84 a 5,65) y los nacidos de mujeres con epilepsia que no reciben tratamiento (RR 1,64; IC del 95%: 0,94 a 2,83) en estudios de cohortes; los datos procedentes de estudios con datos rutinarios de los historiales médicos fueron limitados. En cuanto a la exposición a la fenitoína, la prevalencia de MCG fue elevada en los datos de los estudios de cohortes (5,4%; IC del 95%: 3,6 a 8,1) y en los datos rutinarios de los historiales médicos (6,8%; IC del 95%: 0,1 a 701,2). La prevalencia de MCG fue mayor en los niños expuestos a la fenitoína en comparación con los hijos de mujeres sin epilepsia (RR 3,81; IC del 95%: 1,91 a 7,57) y los hijos de mujeres con epilepsia que no reciben tratamiento (RR 2,01; IC del 95%: 1,29 a 3,12); no hubo datos procedentes de estudios con datos rutinarios de los historiales médicos. Los datos agrupados de los estudios de cohortes indicaron un riesgo significativamente mayor de MCG en los niños expuestos a lamotrigina en comparación con los niños nacidos de mujeres sin epilepsia (RR 1,99; IC del 95%: 1,16 a 3,39); con una diferencia de riesgos (DR) que indica un riesgo 1% mayor de MCG (DR 0,01. IC del 95%: 0,00 a 0,03). Esto no se repitió en la comparación con los hijos de las mujeres con epilepsia que no reciben tratamiento (RR 1,04; IC del 95%: 0,66 a 1,63), que contenía el mayor grupo de niños expuestos a la lamotrigina (> 2700). Además, también se encontró una diferencia no significativa tanto en comparación con los hijos de mujeres sin epilepsia (RR 1,19; IC del 95%: 0,86 a 1,64) como con los hijos de mujeres con epilepsia que no reciben tratamiento (RR 1,00; IC del 95%: 0,79 a 1,28) a partir de los estudios con datos rutinarios. Para la exposición al levetiracetam, los datos agrupados proporcionaron razones de riesgos similares a las de las mujeres sin epilepsia en los estudios de cohortes (RR 2,20; IC del 95%: 0,98 a 4,93) y en los estudios con datos rutinarios de los historiales médicos (RR 0,67; IC del 95%: 0,17 a 2,66). Los resultados agrupados de los estudios de cohortes (RR: 0,71; IC del 95%: 0,39 a 1,28) y de los estudios con datos rutinarios de los historiales médicos (RR: 0,82; IC del 95%: 0,39 a 1,71) respaldan esta afirmación cuando se comparan con los hijos de las mujeres con epilepsia que no reciben tratamiento. En el caso del topiramato, la prevalencia de MCG fue del 3,9% (IC del 95%: 2,3 a 6,5) a partir de los datos de los estudios de cohortes y del 4,1% (0,0 a 27.050,1) a partir de los estudios con datos rutinarios de los historiales médicos. Las razones de riesgos fueron significativamente más altas para los niños expuestos al topiramato en comparación con los hijos de mujeres sin epilepsia en estudios de cohortes (RR 4,07; IC del 95%: 1,64 a 10,14), pero no en una comparación más pequeña con los hijos de mujeres con epilepsia que no reciben tratamiento (RR 1,37; IC del 95%: 0,57 a 3,27); actualmente se dispone de pocos datos a partir de estudios con datos rutinarios de los historiales médicos. La exposición en el útero al topiramato también se asoció con RR significativamente mayores en comparación con otros FAC para las hendiduras orofaciales. Los datos de todos las demás FAC fueron extremadamente limitados. Debido a los diseños observacionales, todos los estudios presentaron un alto riesgo de ciertos sesgos, pero los sesgos observados en los estudios de obtención de datos primarios y el uso secundario de historiales médicos rutinarios fueron diferentes y, en parte, complementarios. Los sesgos estaban equilibrados entre los FAC investigados, y es poco probable que los resultados diferenciales observados entre los FAC se expliquen únicamente por estos sesgos. CONCLUSIONES DE LOS AUTORES: La exposición en el útero a ciertos FAC se asoció con un mayor riesgo de ciertos MCG que, para muchos, depende de la dosis.

HNRNPC haploinsufficiency affects alternative splicing of intellectual disability-associated genes and causes a neurodevelopmental disorder.

Heterogeneous nuclear ribonucleoprotein C (HNRNPC) is an essential, ubiquitously abundant protein involved in mRNA processing. Genetic variants in other members of the HNRNP family have been associated with neurodevelopmental disorders. Here, we describe 13 individuals with global developmental delay, intellectual disability, behavioral abnormalities, and subtle facial dysmorphology with heterozygous HNRNPC germline variants. Five of them bear an identical in-frame deletion of nine amino acids in the extreme C terminus. To study the effect of this recurrent variant as well as HNRNPC haploinsufficiency, we used induced pluripotent stem cells (iPSCs) and fibroblasts obtained from affected individuals. While protein localization and oligomerization were unaffected by the recurrent C-terminal deletion variant, total HNRNPC levels were decreased. Previously, reduced HNRNPC levels have been associated with changes in alternative splicing. Therefore, we performed a meta-analysis on published RNA-seq datasets of three different cell lines to identify a ubiquitous HNRNPC-dependent signature of alternative spliced exons. The identified signature was not only confirmed in fibroblasts obtained from an affected individual but also showed a significant enrichment for genes associated with intellectual disability. Hence, we assessed the effect of decreased and increased levels of HNRNPC on neuronal arborization and neuronal migration and found that either condition affects neuronal function. Taken together, our data indicate that HNRNPC haploinsufficiency affects alternative splicing of multiple intellectual disability-associated genes and that the developing brain is sensitive to aberrant levels of HNRNPC. Hence, our data strongly support the inclusion of HNRNPC to the family of HNRNP-related neurodevelopmental disorders.

Neurodevelopment of babies born to mothers with epilepsy: A prospective observational cohort study.

OBJECTIVE: Despite widespread monotherapy use of lamotrigine or levetiracetam during pregnancy, prospectively collected, blinded child development data are still limited. The NaME (Neurodevelopment of Babies Born to Mothers With Epilepsy) Study prospectively recruited a new cohort of women with epilepsy and their offspring for longitudinal follow-up. METHODS: Pregnant women of <21 weeks gestation (n = 401) were recruited from 21 hospitals in the UK. Data collection occurred during pregnancy (recruitment, trimester 3) and at 12 and 24 months of age. The primary outcome was blinded assessment of infant cognitive, language, and motor development on the Bayley Scales of Infant and Toddler Development (3rd edition) at 24 months of age with supplementary parent reporting on the Vinelands Adaptive Behavior Scales (2nd edition). RESULTS: There were 394 live births, with 277 children (70%) completing the Bayley assessment at 24 months. There was no evidence of an association of prenatal exposure to monotherapy lamotrigine (-.74, SE = 2.9, 95% confidence interval [CI] = -6.5 to 5.0, p = .80) or levetiracetam (-1.57, SE = 3.1, 95% CI = -4.6 to 7.7, p = .62) with poorer infant cognition, following adjustment for other maternal and child factors in comparison to nonexposed children. Similar results were observed for language and motor scores. There was no evidence of an association between increasing doses of either lamotrigine or levetiracetam. Nor was there evidence that higher dose folic acid supplementation (≥5 mg/day) or convulsive seizure exposure was associated with child development scores. Continued infant exposure to antiseizure medications through breast milk was not associated with poorer outcomes, but the number of women breastfeeding beyond 3 months was low. SIGNIFICANCE: These data are reassuring for infant development following in utero exposure to monotherapy lamotrigine or levetiracetam, but child development is dynamic, and future follow-up is required to rule out later emerging effects.

Null and missense mutations of ERI1 cause a recessive phenotypic dichotomy in humans.

ERI1 is a 3'-to-5' exoribonuclease involved in RNA metabolic pathways including 5.8S rRNA processing and turnover of histone mRNAs. Its biological and medical significance remain unclear. Here, we uncover a phenotypic dichotomy associated with bi-allelic ERI1 variants by reporting eight affected individuals from seven unrelated families. A severe spondyloepimetaphyseal dysplasia (SEMD) was identified in five affected individuals with missense variants but not in those with bi-allelic null variants, who showed mild intellectual disability and digital anomalies. The ERI1 missense variants cause a loss of the exoribonuclease activity, leading to defective trimming of the 5.8S rRNA 3' end and a decreased degradation of replication-dependent histone mRNAs. Affected-individual-derived induced pluripotent stem cells (iPSCs) showed impaired in vitro chondrogenesis with downregulation of genes regulating skeletal patterning. Our study establishes an entity previously unreported in OMIM and provides a model showing a more severe effect of missense alleles than null alleles within recessive genotypes, suggesting a key role of ERI1-mediated RNA metabolism in human skeletal patterning and chondrogenesis.

The Role of Genetic Testing in Children Requiring Surgery for Ectopia Lentis.

Non-traumatic ectopia lentis can be isolated or herald an underlying multisystemic disorder. Technological advances have revolutionized genetic testing for many ophthalmic disorders, and this study aims to provide insights into the clinical utility of genetic analysis in paediatric ectopia lentis. Children that underwent lens extraction for ectopia lentis between 2013 and 2017 were identified, and gene panel testing findings and surgical outcomes were collected. Overall, 10/11 cases received a probable molecular diagnosis. Genetic variants were identified in four genes: FBN1 (associated with Marfan syndrome and cardiovascular complications; n = 6), ADAMTSL4 (associated with non-syndromic ectopia lentis; n = 2), LTBP2 (n = 1) and ASPH (n = 1). Parents appeared unaffected in 6/11 cases; the initial presentation of all six of these children was to an ophthalmologist, and only 2/6 had FBN1 variants. Notably, 4/11 cases required surgery before the age of 4 years, and only one of these children carried an FBN1 variant. In summary, in this retrospective cohort study, panel-based genetic testing pointed to a molecular diagnosis in >90% of paediatric ectopia lentis cases requiring surgery. In a subset of study participants, genetic analysis revealed changes in genes that have not been linked to extraocular manifestations and highlighted that extensive systemic investigations were not required in these individuals. We propose the introduction of genetic testing early in the diagnostic pathway in children with ectopia lentis.

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.

3MC syndrome: molecular findings in previously reported and milder patients expand the natural history and phenotypic spectrum.

The 3MC syndromes types 1-3 (MIM#257920, 265050 and 248340, respectively) are rare autosomal recessive genetic disorders caused by pathogenic variants in genes encoding the lectin complement pathway. Patients with 3MC syndrome have a distinctive facial phenotype including hypertelorism, highly arched eyebrows and ptosis. A significant number of patients have bilateral cleft lip and palate and they often exhibit genitourinary and skeletal anomalies. A clinical clue to 3MC syndrome is the presence of a characteristic caudal appendage. Genetic variants in MASP1, COLEC11 and COLEC10 genes have been identified as the causation of this syndrome, yet relatively few patients have been described so far. We consolidate and expand current knowledge of phenotypic features and molecular diagnosis of 3MC syndrome by describing the clinical and molecular findings in five patients. This includes follow-up of two brothers whose clinical phenotypes were first reported by Crisponi et al in 1999. Our study contributes to the evolving clinical and molecular spectrum of 3MC syndrome.

Expanding SPTAN1 monoallelic variant associated disorders: From epileptic encephalopathy to pure spastic paraplegia and ataxia.

PURPOSE: Nonerythrocytic αII-spectrin (SPTAN1) variants have been previously associated with intellectual disability and epilepsy. We conducted this study to delineate the phenotypic spectrum of SPTAN1 variants. METHODS: We carried out SPTAN1 gene enrichment analysis in the rare disease component of the 100,000 Genomes Project and screened 100,000 Genomes Project, DECIPHER database, and GeneMatcher to identify individuals with SPTAN1 variants. Functional studies were performed on fibroblasts from 2 patients. RESULTS: Statistically significant enrichment of rare (minor allele frequency < 1 × 10-5) probably damaging SPTAN1 variants was identified in families with hereditary ataxia (HA) or hereditary spastic paraplegia (HSP) (12/1142 cases vs 52/23,847 controls, p = 2.8 × 10-5). We identified 31 individuals carrying SPTAN1 heterozygous variants or deletions. A total of 10 patients presented with pure or complex HSP/HA. The remaining 21 patients had developmental delay and seizures. Irregular αII-spectrin aggregation was noted in fibroblasts derived from 2 patients with p.(Arg19Trp) and p.(Glu2207del) variants. CONCLUSION: We found that SPTAN1 is a genetic cause of neurodevelopmental disorder, which we classified into 3 distinct subgroups. The first comprises developmental epileptic encephalopathy. The second group exhibits milder phenotypes of developmental delay with or without seizures. The final group accounts for patients with pure or complex HSP/HA.

The inner junction protein CFAP20 functions in motile and non-motile cilia and is critical for vision.

Motile and non-motile cilia are associated with mutually-exclusive genetic disorders. Motile cilia propel sperm or extracellular fluids, and their dysfunction causes primary ciliary dyskinesia. Non-motile cilia serve as sensory/signalling antennae on most cell types, and their disruption causes single-organ ciliopathies such as retinopathies or multi-system syndromes. CFAP20 is a ciliopathy candidate known to modulate motile cilia in unicellular eukaryotes. We demonstrate that in zebrafish, cfap20 is required for motile cilia function, and in C. elegans, CFAP-20 maintains the structural integrity of non-motile cilia inner junctions, influencing sensory-dependent signalling and development. Human patients and zebrafish with CFAP20 mutations both exhibit retinal dystrophy. Hence, CFAP20 functions within a structural/functional hub centered on the inner junction that is shared between motile and non-motile cilia, and is distinct from other ciliopathy-associated domains or macromolecular complexes. Our findings suggest an uncharacterised pathomechanism for retinal dystrophy, and potentially for motile and non-motile ciliopathies in general.

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.

Recommendations for whole genome sequencing in diagnostics for rare diseases.

In 2016, guidelines for diagnostic Next Generation Sequencing (NGS) have been published by EuroGentest in order to assist laboratories in the implementation and accreditation of NGS in a diagnostic setting. These guidelines mainly focused on Whole Exome Sequencing (WES) and targeted (gene panels) sequencing detecting small germline variants (Single Nucleotide Variants (SNVs) and insertions/deletions (indels)). Since then, Whole Genome Sequencing (WGS) has been increasingly introduced in the diagnosis of rare diseases as WGS allows the simultaneous detection of SNVs, Structural Variants (SVs) and other types of variants such as repeat expansions. The use of WGS in diagnostics warrants the re-evaluation and update of previously published guidelines. This work was jointly initiated by EuroGentest and the Horizon2020 project Solve-RD. Statements from the 2016 guidelines have been reviewed in the context of WGS and updated where necessary. The aim of these recommendations is primarily to list the points to consider for clinical (laboratory) geneticists, bioinformaticians, and (non-)geneticists, to provide technical advice, aid clinical decision-making and the reporting of the results.

SOX11 variants cause a neurodevelopmental disorder with infrequent ocular malformations and hypogonadotropic hypogonadism and with distinct DNA methylation profile.

PURPOSE: This study aimed to undertake a multidisciplinary characterization of the phenotype associated with SOX11 variants. METHODS: Individuals with protein altering variants in SOX11 were identified through exome and genome sequencing and international data sharing. Deep clinical phenotyping was undertaken by referring clinicians. Blood DNA methylation was assessed using Infinium MethylationEPIC array. The expression pattern of SOX11 in developing human brain was defined using RNAscope. RESULTS: We reported 38 new patients with SOX11 variants. Idiopathic hypogonadotropic hypogonadism was confirmed as a feature of SOX11 syndrome. A distinctive pattern of blood DNA methylation was identified in SOX11 syndrome, separating SOX11 syndrome from other BAFopathies. CONCLUSION: SOX11 syndrome is a distinct clinical entity with characteristic clinical features and episignature differentiating it from BAFopathies.

Individuals with heterozygous variants in the Wnt-signalling pathway gene FZD5 delineate a phenotype characterized by isolated coloboma and variable expressivity.

BACKGROUND: Anophthalmia, microphthalmia and coloboma are a genetically heterogenous spectrum of developmental eye disorders. Recently, variants in the Wnt-pathway gene Frizzled Class Receptor 5 (FZD5) have been identified in individuals with coloboma and rarely microphthalmia, sometimes with additional phenotypes and variable penetrance. MATERIALS AND METHODS: We identified variants in FZD5 in individuals with developmental eye disorders from the UK (including the DDD Study [www.ddduk.org/access.html]), France and Spain using whole genome/exome sequencing or customized NGS panels of ocular development genes. RESULTS: We report eight new families with FZD5 variants and ocular coloboma. Three individuals presented with additional syndromic features, two explicable by additional variants in other genes (SLC12A2 and DDX3X). In two families initially showing incomplete penetrance, re-examination of apparently unaffected carrier individuals revealed subtle ocular colobomatous phenotypes. Finally, we report two families with microphthalmia in addition to coloboma, representing the second and third reported cases of this phenotype in conjunction with FZD5 variants. CONCLUSIONS: Our findings indicate FZD5 variants are typically associated with isolated ocular coloboma, occasionally microphthalmia, and that extraocular phenotypes are likely to be explained by other gene alterations.

Further delineation of phenotypic spectrum of SCN2A-related disorder.

SCN2A-related disorders include intellectual disability, autism spectrum disorder, seizures, episodic ataxia, and schizophrenia. In this study, the phenotype-genotype association in SCN2A-related disorders was further delineated by collecting detailed clinical and molecular characteristics. Using previously proposed genotype-phenotype hypotheses based on variant function and position, the potential of phenotype prediction from the variants found was examined. Patients were identified through the Deciphering Developmental Disorders study and gene matching strategies. Phenotypic information and variant interpretation evidence were collated. Seventeen previously unreported patients and five patients who had been previously reported (but with minimal phenotypic and segregation data) were included (10 males, 12 females; median age 10.5 years). All patients had developmental delays and the majority had intellectual disabilities. Seizures were reported in 15 of 22 (68.2%), four of 22 (18.2%) had autism spectrum disorder and no patients were reported with episodic ataxia. The majority of variants were de novo. One family had presumed gonadal mosaicism. The correlation of the use of sodium channel-blocking antiepileptic drugs with phenotype or genotype was variable. These data suggest that variant type and position alone can provide some predictive information about the phenotype in a proportion of cases, but more precise assessment of variant function is needed for meaningful phenotype prediction.

Personalised virtual gene panels reduce interpretation workload and maintain diagnostic rates of proband-only clinical exome sequencing for rare disorders.

PURPOSE: The increased adoption of genomic strategies in the clinic makes it imperative for diagnostic laboratories to improve the efficiency of variant interpretation. Clinical exome sequencing (CES) is becoming a valuable diagnostic tool, capable of meeting the diagnostic demand imposed by the vast array of different rare monogenic disorders. We have assessed a clinician-led and phenotype-based approach for virtual gene panel generation for analysis of targeted CES in patients with rare disease in a single institution. METHODS: Retrospective survey of 400 consecutive cases presumed by clinicians to have rare monogenic disorders, referred on singleton basis for targeted CES. We evaluated diagnostic yield and variant workload to characterise the usefulness of a clinician-led approach for generation of virtual gene panels that can incorporate up to three different phenotype-driven gene selection methods. RESULTS: Abnormalities of the nervous system (54.5%), including intellectual disability, head and neck (19%), skeletal system (16%), ear (15%) and eye (15%) were the most common clinical features reported in referrals. Combined phenotype-driven strategies for virtual gene panel generation were used in 57% of cases. On average, 7.3 variants (median=5) per case were retained for clinical interpretation. The overall diagnostic rate of proband-only CES using personalised phenotype-driven virtual gene panels was 24%. CONCLUSIONS: Our results show that personalised virtual gene panels are a cost-effective approach for variant analysis of CES, maintaining diagnostic yield and optimising the use of resources for clinical genomic sequencing in the clinic.

A standard of care for individuals with PIK3CA-related disorders: An international expert consensus statement.

Growth promoting variants in PIK3CA cause a spectrum of developmental disorders, depending on the developmental timing of the mutation and tissues involved. These phenotypically heterogeneous entities have been grouped as PIK3CA-Related Overgrowth Spectrum disorders (PROS). Deep sequencing technologies have facilitated detection of low-level mosaic, often necessitating testing of tissues other than blood. Since clinical management practices vary considerably among healthcare professionals and services across different countries, a consensus on management guidelines is needed. Clinical heterogeneity within this spectrum leads to challenges in establishing management recommendations, which must be based on patient-specific considerations. Moreover, as most of these conditions are rare, affected families may lack access to the medical expertise that is needed to help address the multi-system and often complex medical issues seen with PROS. In March 2019, macrocephaly-capillary malformation (M-CM) patient organizations hosted an expert meeting in Manchester, United Kingdom, to help address these challenges with regards to M-CM syndrome. We have expanded the scope of this project to cover PROS and developed this consensus statement on the preferred approach for managing affected individuals based on our current knowledge.