Heterozygous variants in PRPF8 are associated with neurodevelopmental disorders.

The pre-mRNA-processing factor 8, encoded by PRPF8, is a scaffolding component of a spliceosome complex involved in the removal of introns from mRNA precursors. Previously, heterozygous pathogenic variants in PRPF8 have been associated with autosomal dominant retinitis pigmentosa. More recently, PRPF8 was suggested as a candidate gene for autism spectrum disorder due to the enrichment of sequence variants in this gene in individuals with neurodevelopmental disorders. We report 14 individuals with various forms of neurodevelopmental conditions, found to have heterozygous, predominantly de novo, missense, and loss-of-function variants in PRPF8. These individuals have clinical features that may represent a new neurodevelopmental syndrome.

Changes in genetic variant results over time in pediatric cardiomyopathy and electrophysiology.

Genetic testing for cardiac disorders continues to change. Our objective was to assess trends in variant classification in pediatric arrhythmia and cardiomyopathy. We conducted a retrospective review of patients tested for genetic arrhythmia and cardiomyopathy disorders from 2006-2017. Variants were classified by CLIA laboratories. Trends were assessed by the Spearman correlation. There were 914 variants in 583 patients from 337 families. The total number of tests ordered increased over time, accelerating after 2012. There was a strong positive correlation between the average number of genes tested per panel and year of testing (r = .97, p < .001) and a weak correlation between the year and a decrease in the percentage of clinically actionable variants (r = -.20, p = .005). By 2011, VUS represented >50% of variants reported on panels. Over 12 years, 203 genes were interrogated; one or more variants were reported in 91 of 203 genes (45%). 32% of patients had at least one clinically actionable variant; 28% had at least one VUS. Reclassification is an important long-term issue, with 21.5% variants changing clinical interpretation. We observed an increase over time in three areas: total number of tests ordered, average number of genes/panel, and percentage of VUS. Providers may need to interpret results from 90 + genes, and ongoing education is critical. Due to their specific training in test result interpretation, we recommend the inclusion of a genetic counselor in pediatric electrophysiology and cardiomyopathy teams.

Abnormal Microarray, Clinical Outcomes, and Surgical Risk Scores in Young Children with Cardiac Disease.

The clinical implications of abnormal chromosomal microarray (CMA) remain unclear for children less than 1 year of age with critical heart disease. Our objective was to determine whether abnormal CMA was related to surgical severity scores or to pre-determined clinical outcomes, including cardiac arrest. Retrospective review of children under 1 year of age admitted to a pediatric cardiac intensive care unit from December, 2014 to September, 2017. Associations between CMA result and cardiac arrest, syndromic abnormalities, and extracardiac anomalies were evaluated. A simple and multivariable logistic regression model was used to analyze associations between STAT mortality category and CMA result. The overall prevalence of abnormal microarray was 48/168 (29%), with peak prevalence in AV septal defects and left-sided obstructive lesions. There was no statistical association between surgical severity scores and abnormal CMA (STAT 1/2 vs. 3+, odds ratio 0.56, p = 0.196). Abnormal CMA was associated with a higher prevalence of cardiac arrest (5/48 abnormal CMA vs. 2/120 normal CMA, p = 0.02). Abnormal CMA was associated with a higher frequency of syndromic abnormalities (18/48 abnormal CMA vs. 13/120 normal CMA, p < 0.001). There was a high prevalence of abnormal CMA findings in the pediatric cardiac population less than 1 year of age (29%), associated with cardiac arrest, but not associated with surgical risk score. The absence of a standardized protocol for ordering a CMA in the setting of congenital heart disease results in a highly variable prevalence data.

Clinical diagnostic exome evaluation for an infant with a lethal disorder: genetic diagnosis of TARP syndrome and expansion of the phenotype in a patient with a newly reported RBM10 alteration.

BACKGROUND: Diagnostic Exome Sequencing (DES) has been shown to be an effective tool for diagnosis individuals with suspected genetic conditions. CASE PRESENTATION: We report a male infant born with multiple anomalies including bilateral dysplastic kidneys, cleft palate, bilateral talipes, and bilateral absence of thumbs and first toes. Prenatal testing including chromosome analysis and microarray did not identify a cause for the multiple congenital anomalies. Postnatal diagnostic exome studies (DES) were utilized to find a molecular diagnosis for the patient. Exome sequencing of the proband, mother, and father showed a previously unreported maternally inherited RNA binding motif protein 10 (RBM10) c.1352_1353delAG (p.E451Vfs*66) alteration. Mutations in RBM10 are associated with TARP syndrome, an X-linked recessive disorder originally described with cardinal features of talipes equinovarus, atrial septal defect, Robin sequence, and persistent left superior vena cava. CONCLUSION: DES established a molecular genetic diagnosis of TARP syndrome for a neonatal patient with a poor prognosis in whom traditional testing methods were uninformative and allowed for efficient diagnosis and future reproductive options for the parents. Other reported cases of TARP syndrome demonstrate significant variability in clinical phenotype. The reported features in this infant including multiple hemivertebrae, imperforate anus, aplasia of thumbs and first toes have not been reported in previous patients, thus expanding the clinical phenotype for this rare disorder.

Biallelic loss-of-function variants in PLD1 cause congenital right-sided cardiac valve defects and neonatal cardiomyopathy.

Congenital heart disease is the most common type of birth defect, accounting for one-third of all congenital anomalies. Using whole-exome sequencing of 2718 patients with congenital heart disease and a search in GeneMatcher, we identified 30 patients from 21 unrelated families of different ancestries with biallelic phospholipase D1 (PLD1) variants who presented predominantly with congenital cardiac valve defects. We also associated recessive PLD1 variants with isolated neonatal cardiomyopathy. Furthermore, we established that p.I668F is a founder variant among Ashkenazi Jews (allele frequency of ~2%) and describe the phenotypic spectrum of PLD1-associated congenital heart defects. PLD1 missense variants were overrepresented in regions of the protein critical for catalytic activity, and, correspondingly, we observed a strong reduction in enzymatic activity for most of the mutant proteins in an enzymatic assay. Finally, we demonstrate that PLD1 inhibition decreased endothelial-mesenchymal transition, an established pivotal early step in valvulogenesis. In conclusion, our study provides a more detailed understanding of disease mechanisms and phenotypic expression associated with PLD1 loss of function.

Cardiac Evaluation of Children With a Family History of Sudden Death.

BACKGROUND: After sudden death occurs in the young, first-degree family members should undergo clinical screening for occult cardiac disease, but the diagnostic yield from screening is not well-defined in the United States. OBJECTIVES: The purpose of this study was to determine the clinical predictors of cardiac diagnosis in children referred for evaluation following a sudden death in the family. METHODS: Patients referred for a family history of sudden death were evaluated in a retrospective review from a tertiary pediatric referral center. RESULTS: Among 419 pediatric relatives of 256 decedents, 27% of patients were diagnosed with a disease or had a clinical finding of uncertain significance. Patients were diagnosed with heritable cardiac disease in 39 cases (9.3%). Nonheritable cardiac disease was diagnosed in another 5.5% of patients. Clinical findings of uncertain significance were present in 52 patients (12.4%), including abnormal electrophysiological test results (41 of 52) or imaging test results (11 of 52). Among patients diagnosed with a heritable cardiac disease, the nearest affected relative was almost always a first-degree relative (37 of 39, 95%). The strongest predictors for a successful diagnosis in the patient were an abnormal electrocardiogram and a first-degree relationship to the nearest affected relative (odds ratios: 24.2 and 18.8, respectively). CONCLUSIONS: Children referred for a family history of sudden death receive cardiac disease diagnoses (14%), but clinical findings of uncertain significance increase the challenge of clinical management. The importance of a diagnosis in first-degree affected relatives supports the clinical practice of testing intervening family members first when patients are second- or higher-degree relatives to the decedent.

A Case for Inclusion of Genetic Counselors in Cardiac Care.

Recent advances in genetic testing for heritable cardiac diseases have led to an increasing involvement of the genetic counselor in cardiology practice. We present a series of cases collected from a nationwide query of genetics professionals regarding issues related to cost and utilization of genetic testing. Three themes emerged across cases: (1) choosing the most appropriate genetic test, (2) choosing the best person to test, and (3) interpreting results accurately. These cases demonstrate that involvement of a genetic counselor throughout the evaluation, diagnosis, and continuing management of individuals and families with inherited cardiovascular conditions helps to promote the efficient use of healthcare dollars.

Who are you going to call? Primary care patients' disclosure decisions regarding direct-to-consumer genetic testing.

BACKGROUND: Direct-to-consumer genetic testing (DTCGT) offers risk estimates for a variety of complex diseases and conditions, yet little is known about its impact on actual users, including their decisions about sharing the information gleaned from testing. Ethical considerations include the impact of unsolicited genetic information with variable validity and clinical utility on relatives, and the possible burden to the health care system if revealed to physicians. AIMS: The qualitative study explored primary care patients' views, attitudes, and decision making considerations regarding DTCGT. This article focuses on the disclosure decisions participants made regarding participation, testing, and results of DTCGT, a topic which arose as a secondary aim of the study. METHODS: Through four longitudinal interviews (pre-test, results, 3 and 12 months post-test) we examined twenty primary care patients' decisions, expressed intentions, and actions regarding disclosure to immediate and extended family, friends and coworkers, and physicians about participation in and results of DTCGT. Individual interviews were analyzed using qualitative content analysis and a summative approach to describe the global themes. RESULTS: Most participants disclosed to some immediate family; less than half disclosed to extended family; approximately half talked to friends. Most participants stated they would or might disclose to physicians about DTCGT and a few did. Conceptual themes that emerged from the data analysis include ambivalence about disclosure, consistency between intention and actual disclosure behavior and decisions, and conditional information sharing. CONCLUSIONS: Participants' intentional and actual disclosure patterns offer insight into how they view DTCGT, weigh results, and the potential impact of DTCGT.

Primary care patients' views and decisions about, experience of and reactions to direct-to-consumer genetic testing: a longitudinal study.

Little is known about the decisions and perspectives of participants undergoing direct-to-consumer genetic testing (DTCGT). The aims of this study were to examine the views, attitudes and decision-making factors of primary care patients regarding DTCGT. Their experience of and reactions to testing also emerged during the study. In this longitudinal, qualitative study, 20 primary care patients participated in DTCGT and individual interviews: (1) prior to testing after the informed consent session, (2) after receiving results, (3) 3 months post-test, and (4) 12 months post-test. Interviews included open-ended questions and all transcripts were analyzed using grounded theory, constant comparison methods. Five key themes emerged from data analysis as participants underwent DTCGT and reflected on their decision over time: (1) limited concerns about DTCGT, (2) motivations for testing, (3) expectations of testing, (4) understanding of results, and (5) impact of testing and results. While a few participants expressed concerns before testing, participants were motivated to test by curiosity, gaining actionable knowledge, and altruism. Most were uncertain of what to expect from DTCGT and needed assistance in understanding results. While many reported testing had no significant impact on them, being relieved or pleased after testing was the most common emotional effect. Notably, a few participants made positive health changes in response to testing. Given the paucity of information about primary care patients and DTCGT, this study adds more in-depth information to the emerging research on how such participants' view, make decisions about, experience and react to DTCGT over time. Because uncertainty remains about the accuracy of DTCGT, the response of primary care patients to this testing requires further investigation.

Ubiquilin 1 polymorphisms are not associated with late-onset Alzheimer's disease.

Several studies have reported evidence for linkage of late-onset Alzheimer's disease (LOAD) to chromosome 9. Recently, an intronic polymorphism affecting alternative splicing of exon 8 of ubiquilin 1 (UBQLN1) was reported to be associated with LOAD. We attempted to replicate this observation by genotyping this polymorphism, rs12344615 (also known as UBQ-8i), in a large sample of 1,544 LOAD cases and 1,642 nondemented controls. We did not find any evidence that this single nucleotide polymorphism, or any of six others tested in UBQLN1, increases risk for LOAD.

A scan of chromosome 10 identifies a novel locus showing strong association with late-onset Alzheimer disease.

Strong evidence of linkage to late-onset Alzheimer disease (LOAD) has been observed on chromosome 10, which implicates a wide region and at least one disease-susceptibility locus. Although significant associations with several biological candidate genes on chromosome 10 have been reported, these findings have not been consistently replicated, and they remain controversial. We performed a chromosome 10-specific association study with 1,412 gene-based single-nucleotide polymorphisms (SNPs), to identify susceptibility genes for developing LOAD. The scan included SNPs in 677 of 1,270 known or predicted genes; each gene contained one or more markers, about half (48%) of which represented putative functional mutations. In general, the initial testing was performed in a white case-control sample from the St. Louis area, with 419 LOAD cases and 377 age-matched controls. Markers that showed significant association in the exploratory analysis were followed up in several other white case-control sample sets to confirm the initial association. Of the 1,397 markers tested in the exploratory sample, 69 reached significance (P < .05). Five of these markers replicated at P < .05 in the validation sample sets. One marker, rs498055, located in a gene homologous to RPS3A (LOC439999), was significantly associated with Alzheimer disease in four of six case-control series, with an allelic P value of .0001 for a meta-analysis of all six samples. One of the case-control samples with significant association to rs498055 was derived from the linkage sample (P = .0165). These results indicate that variants in the RPS3A homologue are associated with LOAD and implicate this gene, adjacent genes, or other functional variants (e.g., noncoding RNAs) in the pathogenesis of this disorder.