Many copy-number variants (CNVs) are reported to cause a variety of neurodevelopmental disabilities including intellectual disability, developmental delay, autism, and other phenotypes with ...incomplete penetrance; therefore, not all individuals with a pathogenic CNV are affected. Penetrance estimates vary between studies. A systematic review was conducted to clarify CNV penetrance for 83 recurrent CNVs.
A systematic review using PRISMA guidelines (PROSPERO #CRD42021253955) was conducted to identify penetrance estimates for CNVs associated with neurodevelopment. Pooled analysis was performed using forest plots. The Ottawa Risk of Bias Assessment facilitated evaluation.
Fifteen studies were reviewed in detail with 9 affected cohorts pooled and compared with the gnomAD v4.0 CNV control cohort of 269,885 individuals. Several CNVs previously associated with nonstatistically significant penetrance estimates now exhibit statistically significant differences, contributing to emerging evidence for their pathogenicity (15q24 duplication A-D breakpoints, 15q24.2q24.5 deletion and duplication (FBXO22), 17q11.2 duplication (NF1), 17q21.31 duplication (KANSL1) and 22q11.2 distal duplication). Additionally, evidence is presented for the benign nature of some CNVs (15q11.2 duplication NIPA1 and 2q13 proximal duplication NPHP1).
This is a large-scale systematic review of CNVs associated with neurodevelopment. A synopsis analyzing penetrance and pathogenicity is provided for each of the 83 recurrent CNVs.
Our understanding of the genetics of congenital heart disease (CHD) is rapidly expanding; however, many questions, particularly those relating to sporadic forms of disease, remain unanswered. ...Massively parallel sequencing technology has made significant contributions to the field, both from a diagnostic perspective for patients and, importantly, also from the perspective of disease mechanism. The importance of de novo variation in sporadic disease is a recent highlight, and the genetic link between heart and brain development has been established. Furthermore, evidence of an underlying burden of genetic variation contributing to sporadic and familial forms of CHD has been identified. Although we are still unable to identify the cause of CHD for most patients, recent findings have provided us with a much clearer understanding of the types of variants and their individual contributions and collectively mark an important milestone in our understanding of both familial and sporadic forms of disease.
About 80% of congenital heart disease (CHD) is multifactorial and arises through various combinations of genetic and environmental contributors. About 20% of cases can be attributed to chromosomal ...anomalies, Mendelian syndromes, non-syndromal single gene disorders or teratogens. Down syndrome and velocardiofacial syndrome are the most commonly seen syndromes in patients with CHD. To date, more than 30 genes have been linked to non-syndromal forms of CHD. Their contribution to CHD remains unknown but is presumed to be relatively small. There is limited evidence for the contribution of specific environmental factors to CHD causation. However, folic acid supplementation in the pre- and peri-conception period, ensuring rubella vaccination has been completed before pregnancy, and maintaining good glycaemic control in mothers with diabetes may reduce the risk of CHD in infants. Recurrence risks vary between different types of non-syndromal CHD with multifactorial inheritance, and can be as high as 10% when two or more siblings are affected. Generally, the recurrence risk increases if a parent rather than a sibling is affected, particularly when the affected parent is the mother. Individualised recurrence risks can be generated for members of families affected by CHD after obtaining a detailed family history, including accurate cardiac diagnoses for all affected members. High-throughput genetic techniques can accelerate gene discovery and improve our ability to provide individualised genetic counselling.
Widespread adoption of rapid genomic testing in pediatric critical care requires robust clinical and laboratory pathways that provide equitable and consistent service across health care systems.
To ...prospectively evaluate the performance of a multicenter network for ultra-rapid genomic diagnosis in a public health care system.
Descriptive feasibility study of critically ill pediatric patients with suspected monogenic conditions treated at 12 Australian hospitals between March 2018 and February 2019, with data collected to May 2019. A formal implementation strategy emphasizing communication and feedback, standardized processes, coordination, distributed leadership, and collective learning was used to facilitate adoption.
Ultra-rapid exome sequencing.
The primary outcome was time from sample receipt to ultra-rapid exome sequencing report. The secondary outcomes were the molecular diagnostic yield, the change in clinical management after the ultra-rapid exome sequencing report, the time from hospital admission to the laboratory report, and the proportion of laboratory reports returned prior to death or hospital discharge.
The study population included 108 patients with a median age of 28 days (range, 0 days to 17 years); 34% were female; and 57% were from neonatal intensive care units, 33% were from pediatric intensive care units, and 9% were from other hospital wards. The mean time from sample receipt to ultra-rapid exome sequencing report was 3.3 days (95% CI, 3.2-3.5 days) and the median time was 3 days (range, 2-7 days). The mean time from hospital admission to ultra-rapid exome sequencing report was 17.5 days (95% CI, 14.6-21.1 days) and 93 reports (86%) were issued prior to death or hospital discharge. A molecular diagnosis was established in 55 patients (51%). Eleven diagnoses (20%) resulted from using the following approaches to augment standard exome sequencing analysis: mitochondrial genome sequencing analysis, exome sequencing-based copy number analysis, use of international databases to identify novel gene-disease associations, and additional phenotyping and RNA analysis. In 42 of 55 patients (76%) with a molecular diagnosis and 6 of 53 patients (11%) without a molecular diagnosis, the ultra-rapid exome sequencing result was considered as having influenced clinical management. Targeted treatments were initiated in 12 patients (11%), treatment was redirected toward palliative care in 14 patients (13%), and surveillance for specific complications was initiated in 19 patients (18%).
This study suggests feasibility of ultra-rapid genomic testing in critically ill pediatric patients with suspected monogenic conditions in the Australian public health care system. However, further research is needed to understand the clinical value of such testing, and the generalizability of the findings to other health care settings.
Abstract Background Many genes have been implicated in the development of congenital heart disease (CHD). Next-generation sequencing offers opportunities for genetic testing but is often complicated ...by logistic and interpretative hurdles. Objectives This study sought to apply next-generation sequencing technology to CHD families with multiple affected members using a purpose-designed gene panel to assess diagnostic potential for future clinical applications. Methods We designed a targeted next-generation sequencing gene panel for 57 genes previously implicated in CHD. Probands were screened in 16 families with strong CHD histories and in 15 control subjects. Variants affecting protein-coding regions were classified in silico using prediction programs and filtered according to predicted mode of inheritance, minor allele frequencies, and presence in databases such as dbSNP (Single Nucleotide Polymorphism Database) and ESP (Exome Sequencing Project). Disease segregation studies were conducted in variants identified in CHD cases predicted to be deleterious and with minor allele frequencies <0.1%. Results Thirteen potential disease-causing variants were identified in 9 families. Of these, 5 variants segregated with disease phenotype, revealing a likely molecular diagnosis in 31% of this cohort. Significant increases in the number of “indels, nonsense, and splice” variants, as well as variants classified as “probably damaging” were identified in CHD cases but not in control subjects. Also, there was a significant increase in the total number of “rare” and “low” frequency variants (minor allele frequencies <0.05) in the CHD cases. Conclusions When multiple relatives are affected by CHD, a gene panel–based approach may identify its cause in up to 31% of families. Identifying causal variants has implications for clinical care and future family planning.
Genes associated with nonsyndromic hearing loss are commonly included in reproductive carrier screening panels, which are now routinely offered in preconception and prenatal care in many countries. ...However, there is debate whether hearing loss should be considered a medical condition appropriate for screening. This systematic review assessed research on opinions of those with a lived experience of deafness and the general public regarding genetic testing for deafness in the reproductive setting.
Search of 5 online databases yielded 423 articles, 20 of which met inclusion criteria. We assessed the quality of each study, extracted data, and performed thematic analysis on qualitative studies.
Most studies indicated interest in the use of prenatal diagnosis for deafness. However, there were mixed views, and sometimes strongly held views, expressed regarding the reproductive options that should be available to those with an increased chance of having a child with deafness. Studies were small, from a limited number of countries, and most were too old to include views regarding preimplantation genetic testing.
There is a broad range of views regarding the use of reproductive options for deafness. Further research is essential to explore the benefits and harms of including nonsyndromic hearing loss genes in carrier screening.
Genes associated with non-syndromic hearing loss (NSHL) are frequently included in panels for reproductive genetic carrier screening (RGCS), despite a lack of consensus on whether NSHL is a condition ...appropriate for inclusion in RGCS. We conducted a national online survey using a questionnaire to explore the views of clinicians who facilitate RGCS or provide care to deaf individuals in Australia and New Zealand regarding the inclusion of such genes in RGCS. Results were analysed descriptively, and free-text responses were analysed thematically. The questionnaire was completed by 386 respondents including genetic healthcare providers, obstetricians, ear nose and throat specialists, and general practitioners. The majority of respondents agreed that genes associated with NSHL should be included in RGCS, but there were differences between the groups. 74% of clinicians working in a hearing clinic agreed these genes should be included compared to 67% of genetic healthcare providers, 54% of reproductive care healthcare providers, and 44% of general practitioners. A majority of respondents agreed that moderate to profound deafness is a serious disability, although genetic healthcare providers were less likely to agree than other groups. Overall, respondents agreed that including NSHL in RGCS upholds prospective parents' right to information. However, they also identified major challenges, including concern that screening may express a discriminatory attitude towards those living with deafness. They also identified the complexity of defining the severity of deafness.
Reproductive genetic carrier screening (RGCS) has a history spanning more than 50 years, but for most of that time has been limited to screening for one or a few conditions in targeted population ...groups. The advent of massively parallel sequencing has led to rapid growth in screening for panels of up to hundreds of genes. Such panels typically include numerous genes associated with inborn errors of metabolism (IEM). There are considerable potential benefits for families from screening, but there are also risks and potential pitfalls. The IEM community has a vital role to play in guiding gene selection and assisting with the complexities that arise from screening, including interpreting complex biochemical assays and counselling at‐risk couples about phenotypes and treatments.
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