Clinical utility of chromosomal microarray analysis

Syndromic Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a progressive inherited retinal dystrophy, characterized by the degeneration of photoreceptors, presenting as a rod-cone dystrophy. Approximately 20-30% of patients with RP also exhibit extra-ocular manifestations in the context of a syndrome. This manuscript discusses the broad spectrum of syndromes associated with RP, pathogenic mechanisms, clinical manifestations, differential diagnoses, clinical management approaches, and future perspectives. Given the diverse clinical and genetic landscape of syndromic RP, the diagnosis may be challenging. However, an accurate and timely diagnosis is essential for optimal clinical management, prognostication, and potential treatment. Broadly, the syndromes associated with RP can be categorized into ciliopathies, inherited metabolic disorders, mitochondrial disorders, and miscellaneous syndromes. Among the ciliopathies associated with RP, Usher syndrome and Bardet-Biedl syndrome are the most well-known. Less common ciliopathies include Cohen syndrome, Joubert syndrome, cranioectodermal dysplasia, asphyxiating thoracic dystrophy, Mainzer-Saldino syndrome, and RHYNS syndrome. Several inherited metabolic disorders can present with RP including Zellweger spectrum disorders, adult Refsum disease, α-methylacyl-CoA racemase deficiency, certain mucopolysaccharidoses, ataxia with vitamin E deficiency, abetalipoproteinemia, several neuronal ceroid lipofuscinoses, mevalonic aciduria, PKAN/HARP syndrome, PHARC syndrome, and methylmalonic acidaemia with homocystinuria type cobalamin (cbl) C disease. Due to the mitochondria's essential role in supplying continuous energy to the retina, disruption of mitochondrial function can lead to RP, as seen in Kearns-Sayre syndrome, NARP syndrome, primary coenzyme Q10 deficiency, SSBP1-associated disease, and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency. Lastly, Cockayne syndrome and PERCHING syndrome can present with RP, but they do not fit the abovementioned hierarchy and are thus categorized as 'Miscellaneous'. Several first-in-human clinical trials are underway or in preparation for some of these syndromic forms of RP.

Insurance denials and diagnostic rates in a pediatric genomic research cohort

PURPOSE

This study aimed to assess the amount and types of clinical genetic testing denied by insurance and the rate of diagnostic and candidate genetic findings identified through research in patients who faced insurance denials.

METHODS

Analysis consisted of review of insurance denials in 801 patients enrolled in a pediatric genomic research repository with either no previous genetic testing or previous negative genetic testing result identified through cross-referencing with insurance prior-authorizations in patient medical records. Patients and denials were also categorized by type of insurance coverage. Diagnostic findings and candidate genetic findings in these groups were determined through review of our internal variant database and patient charts.

RESULTS

Of the 801 patients analyzed, 147 had insurance prior-authorization denials on record (18.3%). Exome sequencing and microarray were the most frequently denied genetic tests. Private insurance was significantly more likely to deny testing than public insurance (odds ratio = 2.03 [95% CI = 1.38-2.99] P = .0003). Of the 147 patients with insurance denials, 53.7% had at least 1 diagnostic or candidate finding and 10.9% specifically had a clinically diagnostic finding. Fifty percent of patients with clinically diagnostic results had immediate medical management changes (5.4% of all patients experiencing denials).

CONCLUSION

Many patients face a major barrier to genetic testing in the form of lack of insurance coverage. A number of these patients have clinically diagnostic findings with medical management implications that would not have been identified without access to research testing. These findings support re-evaluation of insurance carriers' coverage policies.

Identification of Extremely Rare Pathogenic CNVs by Array CGH in Saudi Children with Developmental Delay, Congenital Malformations, and Intellectual Disability

Chromosomal imbalance is implicated in developmental delay (DD), congenital malformations (CM), and intellectual disability (ID), and, thus, precise identification of copy number variations (CNVs) is essential. We therefore aimed to investigate the genetic heterogeneity in Saudi children with DD/CM/ID. High-resolution array comparative genomic hybridization (array CGH) was used to detect disease-associated CNVs in 63 patients. Quantitative PCR was done to confirm the detected CNVs. Giemsa banding-based karyotyping was also performed. Array CGH identified chromosomal abnormalities in 24 patients; distinct pathogenic and/or variants of uncertain significance CNVs were found in 19 patients, and aneuploidy was found in 5 patients including 47,XXY (n = 2), 45,X (n = 2) and a patient with trisomy 18 who carried a balanced Robertsonian translocation. CNVs including 9p24p13, 16p13p11, 18p11 had gains/duplications and CNVs, including 3p23p14, 10q26, 11p15, 11q24q25, 13q21.1q32.1, 16p13.3p11.2, and 20q11.1q13.2, had losses/deletions only, while CNVs including 8q24, 11q12, 15q25q26, 16q21q23, and 22q11q13 were found with both gains or losses in different individuals. In contrast, standard karyotyping detected chromosomal abnormalities in ten patients. The diagnosis rate of array CGH (28%, 18/63 patients) was around two-fold higher than that of conventional karyotyping (15.87%, 10/63 patients). We herein report, for the first time, the extremely rare pathogenic CNVs in Saudi children with DD/CM/ID. The reported prevalence of CNVs in Saudi Arabia adds value to clinical cytogenetics.

Expanding the clinical phenotype and genetic spectrum of PURA-related neurodevelopmental disorders

BACKGROUND

PURA-related neurodevelopmental disorders (PURA-NDDs) include 5q31.3 deletion syndrome and PURA syndrome. PURA-NDDs are characterized by neonatal hypotonia, moderate to severe global developmental delay/intellectual disability (GDD/ID), facial dysmorphism, epileptic seizures, nonepileptic movement disorders, and ophthalmological problems. PURA-NDDs have recently been identified and underestimated in neurodevelopmental cohorts, but their diagnosis is still challenging.

METHODS

We retrospectively reviewed the clinical characteristics, genetic spectrum, and diagnostic journey of patients with PURA-NDDs.

RESULTS

We report 2 patients with 5q31.3 microdeletion and 5 with PURA pathogenic variants. They demonstrated hypotonia (7/7, 100%), feeding difficulties (4/5, 80%), and respiratory problems (4/7, 57%) in the neonatal period. All of them had severe GDD/ID and could not achieve independent walking and verbal responses. Distinctive facial features of open-tented upper vermilion, long philtrum, and anteverted nares and poor visual fixation and tracking with or without nystagmus were most commonly found (5/7, 71.4%). There were no significant differences in clinical phenotypes between 5q31.3 microdeletion syndrome and PURA syndrome. PURA-NDDs need to be considered as a differential diagnosis in individuals who show severe hypotonia, including feeding difficulties since birth and severe developmental retardation with distinctive facial and ophthalmological features.

CONCLUSIONS

Our data expands the phenotypic and genetic spectrum of PURA-NDD. Next-generation sequencing methods based on the detailed phenotypic evaluation would shorten the diagnostic delay and would help this rare disorder become a recognizable cause of neurodevelopmental delay.

Genetic counseling for congenital heart disease - Practice resource of the national society of genetic counselors

Congenital heart disease (CHD) is an indication which spans multiple specialties across various genetic counseling practices. This practice resource aims to provide guidance on key considerations when approaching counseling for this particular indication while recognizing the rapidly changing landscape of knowledge within this domain. This resource was developed with consensus from a diverse group of certified genetic counselors utilizing literature relevant for CHD genetic counseling practice and is aimed at supporting genetic counselors who encounter this indication in their practice both pre- and postnatally.

Genetic Testing in Neurodevelopmental Disorders

Neurodevelopmental disorders are the most prevalent chronic medical conditions encountered in pediatric primary care. In addition to identifying appropriate descriptive diagnoses and guiding families to evidence-based treatments and supports, comprehensive care for individuals with neurodevelopmental disorders includes a search for an underlying etiologic diagnosis, primarily through a genetic evaluation. Identification of an underlying genetic etiology can inform prognosis, clarify recurrence risk, shape clinical management, and direct patients and families to condition-specific resources and supports. Here we review the utility of genetic testing in patients with neurodevelopmental disorders and describe the three major testing modalities and their yields - chromosomal microarray, exome sequencing (with/without copy number variant calling), and FMR1 CGG repeat analysis for fragile X syndrome. Given the diagnostic yield of genetic testing and the potential for clinical and personal utility, there is consensus that genetic testing should be offered to all patients with global developmental delay, intellectual disability, and/or autism spectrum disorder. Despite this recommendation, data suggest that a minority of children with autism spectrum disorder and intellectual disability have undergone genetic testing. To address this gap in care, we describe a structured but flexible approach to facilitate integration of genetic testing into clinical practice across pediatric specialties and discuss future considerations for genetic testing in neurodevelopmental disorders to prepare pediatric providers to care for patients with such diagnoses today and tomorrow.

Microcephaly, Hypotonia, and Intracranial Calcifications in an 11-Week-Old Boy

An 11-week-old unvaccinated, term Amish boy initially presented with poor feeding, microcephaly, failure to thrive, and developmental delays. His physical examination was significant for both weight and head circumference being less than the third percentile, and he was noted to have micrognathia, truncal hypotonia, and head lag. He was admitted to the pediatric hospital medicine service for further diagnostic evaluation. Laboratory studies assessing for endocrinological and metabolic etiologies yielded negative results, and imaging studies (including a chest radiograph, echocardiogram, and abdominal ultrasound) were normal. However, intracranial calcifications were noted on a head ultrasound. The etiology of his constellation of symptoms was initially thought to be infectious, but the ultimate diagnosis was not made until after discharge from the pediatric hospital medicine service.

Consanguinity and Autism

PURPOSE OF REVIEW

Consanguinity can increase the risk for autosomal recessive conditions, along with autism spectrum disorder (ASD). Rarely outside of the genetics community is this discussed. Understanding its impact on the development of ASD and increasing awareness for physicians is important.

RECENT FINDINGS

ASD is a polygenic multifactorial disorder associated with morbidity and burden of care. Studies have confirmed its heritability, suspecting to an autosomal recessive transmission. Consanguinity increases the risk for uncovering recessive disorder and its role as an independent contributor for the development of ASD should be examined. With consanguinity being a known risk factor for autosomal recessive conditions, clinicians should routinely screen for it when evaluating for ASD, as this is inconsistently done. If suspected, genetic testing should be also recommended. Understanding current risk as well as future risk and providing families with the education to make the most informed decisions is necessary.

Yield of whole exome sequencing in undiagnosed patients facing insurance coverage barriers to genetic testing

BACKGROUND

Despite growing evidence of diagnostic yield and clinical utility of whole exome sequencing (WES) in patients with undiagnosed diseases, there remain significant cost and reimbursement barriers limiting access to such testing. The diagnostic yield and resulting clinical actions of WES for patients who previously faced insurance coverage barriers have not yet been explored.

METHODS

We performed a retrospective descriptive analysis of clinical WES outcomes for patients facing insurance coverage barriers prior to clinical WES and who subsequently enrolled in the Undiagnosed Diseases Network (UDN). Clinical WES was completed as a result of participation in the UDN. Payer type, molecular diagnostic yield, and resulting clinical actions were evaluated.

RESULTS

Sixty-six patients in the UDN faced insurance coverage barriers to WES at the time of enrollment (67% public payer, 26% private payer). Forty-two of 66 (64%) received insurance denial for clinician-ordered WES, 19/66 (29%) had health insurance through a payer known not to cover WES, and 5/66 (8%) had previous payer denial of other genetic tests. Clinical WES results yielded a molecular diagnosis in 23 of 66 patients (35% [78% pediatric, 65% neurologic indication]). Molecular diagnosis resulted in clinical actions in 14 of 23 patients (61%).

CONCLUSIONS

These data demonstrate that a substantial proportion of patients who encountered insurance coverage barriers to WES had a clinically actionable molecular diagnosis, supporting the notion that WES has value as a covered benefit for patients who remain undiagnosed despite objective clinical findings.

Diagnostic interpretation of genetic studies in patients with primary immunodeficiency diseases: A working group report of the Primary Immunodeficiency Diseases Committee of the American Academy of Allergy, Asthma & Immunology

Genetic testing has become an integral component of the diagnostic evaluation of patients with suspected primary immunodeficiency diseases. Results of genetic testing can have a profound effect on clinical management decisions. Therefore clinical providers must demonstrate proficiency in interpreting genetic data. Because of the need for increased knowledge regarding this practice, the American Academy of Allergy, Asthma & Immunology Primary Immunodeficiency Diseases Committee established a work group that reviewed and summarized information concerning appropriate methods, tools, and resources for evaluating variants identified by genetic testing. Strengths and limitations of tests frequently ordered by clinicians were examined. Summary statements and tables were then developed to guide the interpretation process. Finally, the need for research and collaboration was emphasized. Greater understanding of these important concepts will improve the diagnosis and management of patients with suspected primary immunodeficiency diseases.

Array-CGH increased the diagnostic rate of developmental delay or intellectual disability in Taiwan

BACKGROUND

Unexplained developmental delay or intellectual disability (DD/ID) has an estimated prevalence of about 3%-5% in the general population of Taiwan. Array comparative genomic hybridization (array-CGH) is a high-resolution tool that can detect about 50 Kb chromosome aberrations. A previous study has reported a detection rate of 10%-20% for this array.¹ This study aimed to investigate and compare the diagnosis rate for DD/ID using array-CGH and conventional chromosome study in DD/ID patients in Taiwan.

METHODS

We enrolled 177 patients with DD/ID who underwent array-CGH examination at the MacKay Memory Hospital between June 2010 and September 2017. The copy number variants (CNV) were classified into the following three groups: pathogenic (potential pathologic variant), benign (normal genomic variant), and uncertain clinical significance (variance of uncertain significance, VOUS), according to the ACMG guideline.² RESULTS: Of the 177 enrolled patients, 100 (56.5%) were men and 77 (43.5%) were women. Ages ranged from 3 months to 50 years, with a median age of 5.2 years. Total 32.0% (32/100) male patients had pathogenic CNV, and 32.5% (25/77) female patients had pathogenic CNV. The ratio of pathogenic CNV in male and female patients was not significantly different (p = 0.379). The proportions of pathogenic CNV at <3 years, 3-6 years, 6-12 years, 12-18 years, and >18 years of age were 32.3% (31/96), 19.4% (6/31), 34.8% (8/23), 16.7% (2/12), and 66.7% (10/15), respectively. The overall diagnosed rate of DD/ID with pathogenic CNV was 27.7% (49/177) using array-CGH in this study. There were 105 patients with conventional karyotyping and array-CGH data at the same time. Nineteen (18.1%) patients had visible chromosomal abnormality. Total 32/105 (30.5%) patients could find at least one pathogenic CNVs. The array-CGH had a higher diagnosed rate than the conventional karyotyping in clinical application.

CONCLUSIONS

Although array-CGH could not detect point mutation, balanced translocations, inversions, or low-level mosaicism, the diagnosis rate in clinical application was up to 46.3% and 2.5 times that of conventional karyotyping analysis (18.1%). This study demonstrated that array-CGH is a powerful diagnostic tool and should be the first genetic test instead of conventional karyotyping analysis for patients with unexplained DD/ID.

Meta-analysis and multidisciplinary consensus statement: exome sequencing is a first-tier clinical diagnostic test for individuals with neurodevelopmental disorders

Purpose

For neurodevelopmental disorders (NDDs), etiological evaluation can be a diagnostic odyssey involving numerous genetic tests, underscoring the need to develop a streamlined algorithm maximizing molecular diagnostic yield for this clinical indication. Our objective was to compare the yield of exome sequencing (ES) with that of chromosomal microarray (CMA), the current first-tier test for NDDs.

Methods

We performed a PubMed scoping review and meta-analysis investigating the diagnostic yield of ES for NDDs as the basis of a consensus development conference. We defined NDD as global developmental delay, intellectual disability, and/or autism spectrum disorder. The consensus development conference included input from genetics professionals, pediatric neurologists, and developmental behavioral pediatricians.

Results

After applying strict inclusion/exclusion criteria, we identified 30 articles with data on molecular diagnostic yield in individuals with isolated NDD, or NDD plus associated conditions (such as Rett-like features). Yield of ES was 36% overall, 31% for isolated NDD, and 53% for the NDD plus associated conditions. ES yield for NDDs is markedly greater than previous studies of CMA (15–20%).

Conclusion

Our review demonstrates that ES consistently outperforms CMA for evaluation of unexplained NDDs. We propose a diagnostic algorithm placing ES at the beginning of the evaluation of unexplained NDDs.

Familial segregation of a 5q15-q21.2 deletion associated with facial dysmorphism and speech delay

We report a two-generation family with four females harboring an 8.5Mb heterozygous deletion of 5q15-q21.2 who present with dysmorphic craniofacial features and speech delay. We hypothesize haploinsufficiency of CHD1 to be contributing to the clinical features observed in this family.

The utilization of prenatal microarray: A survey of current genetic counseling practices and barriers

OBJECTIVE

We evaluated what prenatal genetic counselor's (GCs) practices, attitudes, and barriers are in regards to prenatal microarray since the publication of the American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) guidelines for microarray use.

METHODS

This was a survey-based cross-sectional study of English-speaking, board certified or eligible GCs who currently practice prenatal genetic counseling.

RESULTS

Of 192 respondents, 183 (95%) have incorporated chromosome microarray (CMA) into clinical practice, with 64% believing that the benefits of CMA outweigh the harms and 52% agreeing that CMA should be offered to all women regardless of indication. Those who reported being experts/comfortable in their knowledge of CMA (85%) and familiar with current clinical guidelines (86%) were significantly more likely to offer CMA to patients undergoing invasive testing and patients with fetal anomalies. Patient-specific concerns were the largest reported barrier (51%) when GCs do not offer CMA to patients.

CONCLUSION

Our study demonstrates GCs follow guidelines for CMA use when specific indications are involved, but further guidelines are needed regarding CMA use for other routine indications where utility of CMA is not clearly understood. On this basis, ACOG and SMFM should continue revising their guidelines as more information comes to light regarding utility of prenatal CMA for all indications, and organizations like the National Society of Genetic Counselors (NSGC) should consider publishing guidelines on prenatal CMA that are specialized to the GCs sphere of practice.

Paediatricians' expectations and perspectives regarding genetic testing for children with developmental disorders

AIM

To investigate paediatricians' expectations and perspectives of genetic testing for children with developmental disorders.

METHODS

Paediatricians working in a developmental clinic were surveyed each time they ordered a chromosomal microarray (CMA) for a child with developmental disorders. Clinical charts were reviewed. Results were analysed using mixed methodology.

RESULTS

Ninety-seven % (73/76) of surveys were completed. Paediatricians reported that 36% of parents had difficulties understanding genetic testing and that 40% seemed anxious. The majority expected testing to have positive impacts on children/families. The themes raised were (i) clarifying the diagnosis (56%), (ii) understanding the aetiology of the condition (55%), (iii) enabling prenatal diagnosis/counselling (43%), (iv) improving medical care for the child (15%) and (v) decreasing parental guilt/anxiety (8%). Less than half anticipated negative impacts; 74% expected that the most helpful result for their patient would be an abnormal result explaining the disorder. Among the 73 children for whom CMA was ordered, 81% got tested: 66% of the results were normal, 19% were abnormal and contributed to explain the condition and 12% were abnormal but of unknown significance.

CONCLUSION

Paediatricians generally expect many positive and less negative impacts of genetic testing for children with developmental disorders. Parental perspectives are needed.

Chromosomal microarray analysis in a cohort of underrepresented population identifies SERINC2 as a novel candidate gene for autism spectrum disorder

Chromosomal microarray (CMA) is now recognized as the first-tier genetic test for detection of copy number variations (CNVs) in patients with autism spectrum disorder (ASD). The aims of this study were to identify known and novel ASD associated-CNVs and to evaluate the diagnostic yield of CMA in Thai patients with ASD. The Infinium CytoSNP-850K BeadChip was used to detect CNVs in 114 Thai patients comprised of 68 retrospective ASD patients (group 1) with the use of CMA as a second line test and 46 prospective ASD and developmental delay patients (group 2) with the use of CMA as the first-tier test. We identified 7 (6.1%) pathogenic CNVs and 22 (19.3%) variants of uncertain clinical significance (VOUS). A total of 29 patients with pathogenic CNVs and VOUS were found in 22% (15/68) and 30.4% (14/46) of the patients in groups 1 and 2, respectively. The difference in detected CNV frequencies between the 2 groups was not statistically significant (Chi square = 1.02, df = 1, P = 0.31). In addition, we propose one novel ASD candidate gene, SERINC2, which warrants further investigation. Our findings provide supportive evidence that CMA studies using population-specific reference databases in underrepresented populations are useful for identification of novel candidate genes.

Assessment of large copy number variants in patients with apparently isolated congenital left-sided cardiac lesions reveals clinically relevant genomic events

Congenital left-sided cardiac lesions (LSLs) are a significant contributor to the mortality and morbidity of congenital heart disease (CHD). Structural copy number variants (CNVs) have been implicated in LSL without extra-cardiac features; however, non-penetrance and variable expressivity have created uncertainty over the use of CNV analyses in such patients. High-density SNP microarray genotyping data were used to infer large, likely-pathogenic, autosomal CNVs in a cohort of 1,139 probands with LSL and their families. CNVs were molecularly confirmed and the medical records of individual carriers reviewed. The gene content of novel CNVs was then compared with public CNV data from CHD patients. Large CNVs (>1 MB) were observed in 33 probands (∼3%). Six of these were de novo and 14 were not observed in the only available parent sample. Associated cardiac phenotypes spanned a broad spectrum without clear predilection. Candidate CNVs were largely non-recurrent, associated with heterozygous loss of copy number, and overlapped known CHD genomic regions. Novel CNV regions were enriched for cardiac development genes, including seven that have not been previously associated with human CHD. CNV analysis can be a clinically useful and molecularly informative tool in LSLs without obvious extra-cardiac defects, and may identify a clinically relevant genomic disorder in a small but important proportion of these individuals.

Analytical and Clinical Validity Study of FirstStepDx PLUS: A Chromosomal Microarray Optimized for Patients with Neurodevelopmental Conditions

Introduction:

Chromosomal microarray analysis (CMA) is recognized as the first-tier test in the genetic evaluation of children with developmental delays, intellectual disabilities, congenital anomalies and autism spectrum disorders of unknown etiology.

Array Design:

To optimize detection of clinically relevant copy number variants associated with these conditions, we designed a whole-genome microarray, FirstStep^Dx PLUS (FSDX). A set of 88,435 custom probes was added to the Affymetrix CytoScanHD platform targeting genomic regions strongly associated with these conditions. This combination of 2,784,985 total probes results in the highest probe coverage and clinical yield for these disorders.

Results and Discussion:

Clinical testing of this patient population is validated on DNA from either non-invasive buccal swabs or traditional blood samples. In this report we provide data demonstrating the analytic and clinical validity of FSDX and provide an overview of results from the first 7,570 consecutive patients tested clinically. We further demonstrate that buccal sampling is an effective method of obtaining DNA samples, which may provide improved results compared to traditional blood sampling for patients with neurodevelopmental disorders who exhibit somatic mosaicism.

Clinical Utility of a Comprehensive, Whole Genome CMA Testing Platform in Pediatrics: A Prospective Randomized Controlled Trial of Simulated Patients in Physician Practices

BACKGROUND

Developmental disorders (DD), including autism spectrum disorder (ASD) and intellectual disability (ID), are a common group of clinical manifestations caused by a variety of genetic abnormalities. Genetic testing, including chromosomal microarray (CMA), plays an important role in diagnosing these conditions, but CMA can be limited by incomplete coverage of genetic abnormalities and lack of guidance for conditions rarely seen by treating physicians.

METHODS

We conducted a longitudinal, randomized controlled trial investigating the impact of a higher resolution 2.8 million (MM) probe-CMA test on the quality of care delivered by practicing general pediatricians and specialists. To overcome the twin problems of finding an adequate sample size of multiple rare conditions and under/incorrect diagnoses, we used standardized simulated patients known as CPVs. Physicians, randomized into control and intervention groups, cared for the CPV pediatric patients with DD/ASD/ID. Care responses were scored against evidence-based criteria. In round one, participants could order diagnostic tests including existing CMA tests. In round two, intervention physicians could order the 2.8MM probe-CMA test. Outcome measures included overall quality of care and quality of the diagnosis and treatment plan.

RESULTS

Physicians ordering CMA testing had 5.43% (p<0.001) higher overall quality scores than those who did not. Intervention physicians ordering the 2.8MM probe-CMA test had 7.20% (p<0.001) higher overall quality scores. Use of the 2.8MM probe-CMA test led to a 10.9% (p<0.001) improvement in the diagnosis and treatment score. Introduction of the 2.8MM probe-CMA test led to significant improvements in condition-specific interventions including an 8.3% (p = 0.04) improvement in evaluation and therapy for gross motor delays caused by Hunter syndrome, a 27.5% (p = 0.03) increase in early cognitive intervention for FOXG1-related disorder, and an 18.2% (p<0.001) improvement in referrals to child neurology for Dravet syndrome.

CONCLUSION

Physician use of the 2.8MM probe-CMA test significantly improves overall quality as well as diagnosis and treatment quality for simulated cases of pediatric DD/ASD/ID patients, and delivers additional clinical utility over existing CMA tests.

Chromosomal Microarray Analysis of Consecutive Individuals with Autism Spectrum Disorders Using an Ultra-High Resolution Chromosomal Microarray Optimized for Neurodevelopmental Disorders

Copy number variants (CNVs) detected by chromosomal microarray analysis (CMA) significantly contribute to understanding the etiology of autism spectrum disorder (ASD) and other related conditions. In recognition of the value of CMA testing and its impact on medical management, CMA is in medical guidelines as a first-tier test in the evaluation of children with these disorders. As CMA becomes adopted into routine care for these patients, it becomes increasingly important to report these clinical findings. This study summarizes the results of over 4 years of CMA testing by a CLIA-certified clinical testing laboratory. Using a 2.8 million probe microarray optimized for the detection of CNVs associated with neurodevelopmental disorders, we report an overall CNV detection rate of 28.1% in 10,351 consecutive patients, which rises to nearly 33% in cases without ASD, with only developmental delay/intellectual disability (DD/ID) and/or multiple congenital anomalies (MCA). The overall detection rate for individuals with ASD is also significant at 24.4%. The detection rate and pathogenic yield of CMA vary significantly with the indications for testing, age, and gender, as well as the specialty of the ordering doctor. We note discrete differences in the most common recurrent CNVs found in individuals with or without a diagnosis of ASD.

Clinical Performance of an Ultrahigh Resolution Chromosomal Microarray Optimized for Neurodevelopmental Disorders

Copy number variants (CNVs) as detected by chromosomal microarray analysis (CMA) significantly contribute to the etiology of neurodevelopmental disorders, such as developmental delay (DD), intellectual disability (ID), and autism spectrum disorder (ASD). This study summarizes the results of 3.5 years of CMA testing by a CLIA-certified clinical testing laboratory 5487 patients with neurodevelopmental conditions were clinically evaluated for rare copy number variants using a 2.8-million probe custom CMA optimized for the detection of CNVs associated with neurodevelopmental disorders. We report an overall detection rate of 29.4% in our neurodevelopmental cohort, which rises to nearly 33% when cases with DD/ID and/or MCA only are considered. The detection rate for the ASD cohort is also significant, at 25%. Additionally, we find that detection rate and pathogenic yield of CMA vary significantly depending on the primary indications for testing, the age of the individuals tested, and the specialty of the ordering doctor. We also report a significant difference between the detection rate on the ultrahigh resolution optimized array in comparison to the array from which it originated. This increase in detection can significantly contribute to the efficient and effective medical management of neurodevelopmental conditions in the clinic.

Chromosomal Microarrays: Understanding Genetics of Neurodevelopmental Disorders and Congenital Anomalies

Chromosomal microarray (CMA) testing, used to identify DNA copy number variations (CNVs), has helped advance knowledge about genetics of human neurodevelopmental disease and congenital anomalies. It has aided in discovering new CNV syndromes and uncovering disease genes. It has discovered CNVs that are not fully penetrant and/or cause a spectrum of phenotypes, including intellectual disability, autism, schizophrenia, and dysmorphisms. Such CNVs can pose challenges to genetic counseling. They also have helped increase knowledge of genetic risk factors for neurodevelopmental disease and raised awareness of possible shared etiologies among these variable phenotypes. Advances in CMA technology allow CNV identification at increasingly finer scales, improving detection of pathogenic changes, although these sometimes are difficult to distinguish from normal population variation. This paper confronts some of the challenges uncovered by CMA testing while reviewing advances in genetics and the clinical use of this test that has replaced standard karyotyping in most genetic evaluations.

Parents' perceptions of the usefulness of chromosomal microarray analysis for children with autism spectrum disorders

Clinical guidelines recommend chromosomal microarray analysis (CMA) for all children with autism spectrum disorders (ASDs). We explored the test's perceived usefulness among parents of children with ASD who had undergone CMA, and received a result categorized as pathogenic, variant of uncertain significance, or negative. Fifty-seven parents participated in a semi-structured telephone interview, and 50 also completed a survey. Most parents reported that CMA was helpful for their child and family. Major themes regarding perceived usefulness were: medical care, educational and behavioral interventions, causal explanation, information for family members, and advancing knowledge. Limits to utility, uncertainties and negative outcomes were also identified. Our findings highlight the importance of considering both health and non-health related utility in genomic testing.

Low Rates of Genetic Testing in Children With Developmental Delays, Intellectual Disability, and Autism Spectrum Disorders

To explore the routine and effective use of genetic testing for patients with intellectual disability and developmental delay (ID/DD), we conducted a prospective, randomized observational study of 231 general pediatricians (40%) and specialists (60%), using simulated patients with 9 rare pediatric genetic illnesses. Participants cared for 3 randomly assigned simulated patients, and care responses were scored against explicit evidence-based criteria. Scores were calculated as a percentage of criteria completed. Care varied widely, with a median overall score of 44.7% and interquartile range of 36.6% to 53.7%. Diagnostic accuracy was low: 27.4% of physicians identified the correct primary diagnosis. Physicians ordered chromosomal microarray analysis in 55.7% of cases. Specific gene sequence testing was used in 1.4% to 30.3% of cases. This study demonstrates that genetic testing is underutilized, even for widely available tests. Further efforts to educate physicians on the clinical utility of genetic testing may improve diagnosis and care in these patients.

Cost Effectiveness of Using Array-CGH for Diagnosing Learning Disability

OBJECTIVE

To undertake a cost-effectiveness analysis of using microarray comparative genomic hybridisation (array-CGH) as a first-line test versus as a second-line test for the diagnosis of causal chromosomal abnormalities in patients referred to a NHS clinical genetics service in the U.K. with idiopathic learning disability, developmental delay and/or congenital anomalies.

METHODS

A cost-effectiveness study was conducted. The perspective is that of a U.K. NHS clinical genetics service provider (with respect to both costs and outcomes). A cohort of patients (n = 1590) referred for array-CGH testing of undiagnosed learning disability and developmental delay by a single NHS regional clinical genetics service (South East Thames Regional Genetics Service), were split into a before-and-after design where 742 patients had array-CGH as a second-line test (before group-comparator intervention) and 848 patients had array-CGH as a first-line test (after group-evaluated intervention). The mean costs were calculated from the clinical genetics testing pathway constructed for each patient including the costs of genetic testing undertaken and clinical appointments scheduled. The outcome was the number of diagnoses each intervention produced so that a mean cost-per-diagnosis could be calculated. The cost effectiveness of the two interventions was calculated as an incremental cost-effectiveness ratio to produce an incremental cost-per-diagnosis (in 2013 GBP). Sensitivity analyses were conducted by altering both costs and effects to check the validity of the outcome.

RESULTS

The incremental mean cost of testing patients using the first-line testing strategy was -GBP241.56 (95% CIs -GBP256.93 to -GBP226.19) and the incremental mean gain in the percentage diagnoses was 0.39% (95% CIs -2.73 to 3.51%), which equates to an additional 1 diagnosis per 256 patients tested. This cost-effectiveness study comparing these two strategies estimates that array-CGH first-line testing dominates second-line testing because it was both less costly and as effective. The sensitivity analyses conducted (adjusting both costs and effects) supported the dominance of the first-line testing strategy (i.e. lower cost and as effective).

CONCLUSIONS

The first-line testing strategy was estimated to dominate the second-line testing strategy because it was both less costly and as effective. These findings are relevant to the wider UK NHS clinical genetics service, with two key strengths of this study being the appropriateness of the comparator interventions and the direct applicability of the patient cohort within this study and the wider UK patient population.

Dilemmas in Prenatal Chromosomal Diagnosis Revealed Through a Single Center's 30 Years' Experience and 90,000 Cases

INTRODUCTION

The aim of this article is to provide a perspective of prenatal chromosomal diagnosis (PCD) derived from a single center's evolving experience from ∼90,000 consecutive prenatal cases and to highlight important issues and current dilemmas.

MATERIALS AND METHODS

Prenatal cases in this study (1985-2013) were referred for various indications, and PCD was performed by standard karyotype in 84,255 cases, multiplex ligation-dependent probe amplification (MLPA) panel in 3,010 cases and standalone array comparative genomic hybridization (aCGH) in 3,122 cases.

RESULTS

Classic karyotype revealed 1.7 and 7.9% of pathological cases in amniotic fluid and CVS samples, respectively, with common aneuploidies accounting for 59.6 and 64.3% of the total abnormal. Molecular approaches increased the diagnostic yield by 0.6% for MLPA and 1.6% for aCGH, uncovering pathogenic chromosomal abnormalities undetectable by karyotype analysis.

CONCLUSIONS

Current molecular diagnostic capabilities and the recent introduction of noninvasive prenatal testing (NIPT) point to one current major dilemma in PCD, with serious implications in genetic counseling, relating on the one hand to reaping the benefits from the high detection rate afforded through aCGH but accepting an invasive risk, and on the other hand, offering a lower detection rate practically only for Down syndrome, with minimal invasive risk.

Capturing the clinical utility of genomic testing: medical recommendations following pediatric microarray

Interpretation of pediatric chromosome microarray (CMA) results presents diagnostic and medical management challenges. Understanding management practices triggered by CMA will inform clinical utility and resource planning. Using a retrospective cohort design, we extracted clinical and management-related data from the records of 752 children with congenital anomalies and/or developmental delay who underwent CMA in an academic pediatric genetics clinic (2009–2011). Frequency distributions and relative rates (RR) of post-CMA medical recommendations in children with reportable and benign CMA results were calculated. Medical recommendations were provided for 79.6% of children with reportable results and 62.0% of children with benign results. Overall, recommendations included specialist consultation (40.8%), imaging (32.5%), laboratory investigations (17.2%), surveillance (4.6%), and family investigations (4.9%). Clinically significant variants and variants of uncertain clinical significance were associated with higher and slightly higher rates of management recommendations, respectively, compared with benign/no variants (RR=1.34; 95% CI (1.22–1.47); RR=1.23; 95% CI (1.09–1.38)). Recommendation rates for clinically significant versus uncertain results depended upon how uncertainty was classified (RR_broad=1.09; 95% CI (0.99–1.2); RR_narrow=1.12; 95% CI (1.02–1.24)). Recommendation rates also varied by the child's age and provider type. In conclusion, medical recommendations follow CMA for the majority of children. Compared with benign CMA results, clinically significant CMA variants are a significant driver of pediatric medical recommendations. Variants of uncertain clinical significance drive recommendations, but to a lesser extent. As a broadening range of specialists will need to respond to CMA results, targeted capacity building is warranted.

The clinical impact of chromosomal microarray on paediatric care in Hong Kong

Objective

To evaluate the clinical impact of chromosomal microarray (CMA) on the management of paediatric patients in Hong Kong.

Methods

We performed NimbleGen 135k oligonucleotide array on 327 children with intellectual disability (ID)/developmental delay (DD), autism spectrum disorders (ASD), and/or multiple congenital anomalies (MCAs) in a university-affiliated paediatric unit from January 2011 to May 2013. The medical records of patients were reviewed in September 2013, focusing on the pathogenic/likely pathogenic CMA findings and their “clinical actionability” based on established criteria.

Results

Thirty-seven patients were reported to have pathogenic/likely pathogenic results, while 40 had findings of unknown significance. This gives a detection rate of 11% for clinically significant (pathogenic/likely pathogenic) findings. The significant findings have prompted clinical actions in 28 out of 37 patients (75.7%), while the findings with unknown significance have led to further management recommendation in only 1 patient (p<0.001). Nineteen out of the 28 management recommendations are “evidence-based” on either practice guidelines endorsed by a professional society (n = 9, Level 1) or peer-reviewed publications making medical management recommendation (n = 10, Level 2). CMA results impact medical management by precipitating referral to a specialist (n = 24); diagnostic testing (n = 25), surveillance of complications (n = 19), interventional procedure (n = 7), medication (n = 15) or lifestyle modification (n = 12).

Conclusion

The application of CMA in children with ID/DD, ASD, and/or MCAs in Hong Kong results in a diagnostic yield of ∼11% for pathogenic/likely pathogenic results. Importantly the yield for clinically actionable results is 8.6%. We advocate using diagnostic yield of clinically actionable results to evaluate CMA as it provides information of both clinical validity and clinical utility. Furthermore, it incorporates evidence-based medicine into the practice of genomic medicine. The same framework can be applied to other genomic testing strategies enabled by next-generation sequencing.

A qualitative study of healthcare providers' perspectives on the implications of genome-wide testing in pediatric clinical practice

The utilization of genome-wide chromosomal microarray analysis (CMA) in pediatric clinical practice provides an opportunity to consider how genetic diagnostics is evolving, and to prepare for the clinical integration of genome-wide sequencing technologies. We conducted semi-structured interviews with 15 healthcare providers (7 genetic counselors, 4 medical geneticists, and 4 non-genetics providers) to investigate the impact of CMA on clinical practice, and implications for providers, patients and families. Interviews were analyzed qualitatively using content analysis. Most providers reported that genomic testing enhanced their professional experience and was beneficial to patients, primarily due to the improved diagnostic rate compared with earlier chromosomal studies. Other effects on practice included moving towards genotype-first diagnosis and broadening indications for chromosomal testing. Opinions varied concerning informed consent and disclosure of results. The duty to disclose incidental findings (IFs) was noted; however concerns were raised about potential psychosocial harms of disclosing pre-symptomatic findings. Tensions were revealed between the need for comprehensive informed consent for all families and the challenges of communicating time-consuming and potentially anxiety-provoking information regarding uncertain and incidental findings that may be relevant only in rare cases. Genetic counselors can play an important role in liaising with families, health professionals and testing laboratories, providing education and guidance to non-genetics providers, and enabling families to receive adequate pre-and post-test information and follow-up care.

Predictive diagnostic value for the clinical features accompanying intellectual disability in children with pathogenic copy number variations: a multivariate analysis

Background

Array comparative genomic hybridization (a-CGH) has become the first-tier investigation in patients with unexplained developmental delay/intellectual disability (DD/ID). Although the costs are progressively decreasing, a-CGH is still an expensive and labour-intensive technique: for this reason a definition of the categories of patients that can benefit the most of the analysis is needed. Aim of the study was to retrospectively analyze the clinical features of children with DD/ID attending the outpatient clinic of the Mother & Child Department of the University Hospital of Modena subjected to a-CGH, to verify by uni- and multivariate analysis the independent predictors of pathogenic CNVs.

Methods

116 patients were included in the study. Data relative to the CNVs and to the patients’ clinical features were analyzed for genotype/phenotype correlations.

Results and conclusions

27 patients (23.3%) presented pathogenic CNVs (21 deletions, 3 duplications and 3 cases with both duplications and deletions). Univariate analysis showed a significant association of the pathogenic CNVs with the early onset of symptoms (before 1 yr of age) and the presence of malformations and dysmorphisms. Logistic regression analysis showed a significant independent predictive value for diagnosing a pathogenic CNV for malformations (P = 0.002) and dysmorphisms (P = 0.023), suggesting that those features should address a-CGH analysis as a high-priority test for diagnosis.

The impact of chromosomal microarray on clinical management: a retrospective analysis

PURPOSE

Chromosomal microarray has been widely adopted as the first-tier clinical test for individuals with multiple congenital anomalies, developmental delay, intellectual disability, and autism spectrum disorders. Although chromosomal microarray has been extensively shown to provide a higher diagnostic yield than conventional cytogenetic methods, some health insurers refuse to provide coverage for this test, claiming that it is experimental and does not affect patients' clinical management.

METHODS

We retrospectively reviewed the electronic medical records of all patients who had abnormal chromosomal microarray findings reported by our laboratory over a 3-year period and quantified the management recommendations made in response to these results.

RESULTS

Abnormal chromosomal microarray findings were reported for 12.7% of patients (227/1,780). For patients with clinical follow-up notes available, these results had management implications for 54.5% of patients in the entire abnormal cohort (102/187) and for 42.1% of patients referred for isolated neurodevelopmental disorders (16/38). Recommendations included pharmacological treatment, cancer-related screening or exclusion of screening, contraindications, and referrals for further evaluation.

CONCLUSION

These results empirically demonstrate the clinical utility of chromosomal microarray by providing evidence that management was directly affected for the majority of patients in our cohort with abnormal chromosomal microarray findings.

Three clinical experiences with SNP array results consistent with parental incest: a narrative with lessons learned

Single nucleotide polymorphism microarrays have the ability to reveal parental consanguinity which may or may not be known to healthcare providers. Consanguinity can have significant implications for the health of patients and for individual and family psychosocial well-being. These results often present ethical and legal dilemmas that can have important ramifications. Unexpected consanguinity can be confounding to healthcare professionals who may be unprepared to handle these results or to communicate them to families or other appropriate representatives. There are few published accounts of experiences with consanguinity and SNP arrays. In this paper we discuss three cases where molecular evidence of parental incest was identified by SNP microarray. We hope to further highlight consanguinity as a potential incidental finding, how the cases were handled by the clinical team, and what resources were found to be most helpful. This paper aims to contribute further to professional discourse on incidental findings with genomic technology and how they were addressed clinically. These experiences may provide some guidance on how others can prepare for these findings and help improve practice. As genetic and genomic testing is utilized more by non-genetics providers, we also hope to inform about the importance of engaging with geneticists and genetic counselors when addressing these findings.

Genetic testing and genetic counseling among Medicaid-enrolled children with autism spectrum disorder in 2001 and 2007

The rise in the prevalence of autism spectrum disorder (ASD) has resulted in increased efforts to understand the causes of this complex set of disorders that emerge early in childhood. Although research in this area is underway and yielding useful, but complex information about ASD, guidelines for the use of genetic testing and counseling among children with ASD conflict. The purpose of this study was to determine the frequency of use of genetic testing and counseling before the widespread implementation of clinical chromosomal microarray (CMA) to establish a baseline for the use of both services and to investigate potential disparities in the use of both services among children with ASD. We found that about two-thirds of children with ASD received genetic testing or counseling and the use of both services is increasing with time, even in the pre-CMA era. Being female and having a comorbid intellectual disability diagnosis both increased the likelihood of receiving genetic testing and genetic counseling. Initial discrepancies in the use of both services based on race/ethnicity suggest that troubling disparities observed in other services delivered to children with ASD and other mental health disorders persist in genetic testing and counseling as well. These results should incentivize further investigation of the impact of genetic testing and counseling on children with ASD and their families, and should drive efforts to explore and confront disparities in the delivery of these services, particularly with the advancing scientific research on this topic.

Congenital malformations associated with assisted reproductive technology: a California statewide analysis

BACKGROUND

Management of congenital malformations comprises a large part of pediatric surgical care. Despite increasing utilization of assisted reproductive technology (ART) and fertility-related services (FRS), associations with birth defects are poorly understood.

METHODS

Infants born after ART or FRS were identified from the California Linked Birth Cohort Dataset from 2006 to 2007 and compared to propensity matched infants conceived naturally. Factors associated with major congenital malformations were evaluated using Firth logistic regression.

RESULTS

With a cohort of 4,795 infants born after ART and 46,025 naturally conceived matched controls, major congenital malformations were identified in 3,463 infants. Malformations were increased for ART infants (9.0% vs. 6.6%, p<0.001). After adjusting for infant and maternal factors, ART infants exhibited increased odds of major malformations overall (OR 1.25, 95% CI 1.12-1.39), specifically defects of the eye (OR 1.81, 95% CI 1.04-3.16), head and neck (OR 1.37, 95% CI 1.00-1.86), heart (OR 1.41, 95% CI 1.22-1.64), and genitourinary system (OR 1.40, 95% CI 1.09-1.82). The likelihood of birth defects was increased for multiples (OR 1.35, 95% CI 1.18-1.54) and not singletons. Odds of congenital malformation after FRS alone (n=1,749) were non-significant.

CONCLUSION

ART contributes a significant risk of congenital malformation and may be more pronounced for multiples. Accurate counseling for parents considering ART and multidisciplinary coordination of care prior to delivery are warranted.