Evaluating use of changing technologies for rapid next-generation sequencing in pediatrics.

BACKGROUND: Rapid next-generation sequencing (NGS) offers the potential to shorten the diagnostic process and improve the care of acutely ill children. The goal of this study was to report our findings, including benefits and limitations, of a targeted NGS panel and rapid genome sequencing (rGS) in neonatal and pediatric acute clinical care settings. METHODS: Retrospective analysis of patient characteristics, diagnostic yields, turnaround time, and changes in management for infants and children receiving either RapSeq, a targeted NGS panel for 4500+ genes, or rGS, at the University of Utah Hospital and Primary Children's Hospital, from 2015 to 2020. RESULTS: Over a 5-year period, 142 probands underwent rapid NGS: 66 received RapSeq and 76 rGS. Overall diagnostic yield was 39%. In the majority of diagnostic cases, there were one or more changes in clinical care management. Of note, 7% of diagnoses identified by rGS would not have been identified by RapSeq. CONCLUSIONS: Our results indicate that rapid NGS impacts acute pediatric care in real-life clinical settings. Although affected by patient selection criteria, diagnostic yields were similar to those from clinical trial settings. Future studies are needed to determine relative advantages, including cost, turnaround time, and benefits for patients, of each approach in specific clinical circumstances. IMPACT: The use of comprehensive Mendelian gene panels and genome sequencing in the clinical setting allows for early diagnosis of patients in neonatal, pediatric, and cardiac intensive care units and impactful change in management. Diagnoses led to significant changes in management for several patients in lower acuity inpatient units supporting further exploration of the utility of rapid sequencing in these settings. This study reviews the limitations of comparing sequencing platforms in the clinical setting and the variables that should be considered in evaluating diagnostic rates across studies.

Interoperable genetic lab test reports: mapping key data elements to HL7 FHIR specifications and professional reporting guidelines.

OBJECTIVE: In many cases, genetic testing labs provide their test reports as portable document format files or scanned images, which limits the availability of the contained information to advanced informatics solutions, such as automated clinical decision support systems. One of the promising standards that aims to address this limitation is Health Level Seven International (HL7) Fast Healthcare Interoperability Resources Clinical Genomics Implementation Guide-Release 1 (FHIR CG IG STU1). This study aims to identify various data content of some genetic lab test reports and map them to FHIR CG IG specification to assess its coverage and to provide some suggestions for standard development and implementation. MATERIALS AND METHODS: We analyzed sample reports of 4 genetic tests and relevant professional reporting guidelines to identify their key data elements (KDEs) that were then mapped to FHIR CG IG. RESULTS: We identified 36 common KDEs among the analyzed genetic test reports, in addition to other unique KDEs for each genetic test. Relevant suggestions were made to guide the standard implementation and development. DISCUSSION AND CONCLUSION: The FHIR CG IG covers the majority of the identified KDEs. However, we suggested some FHIR extensions that might better represent some KDEs. These extensions may be relevant to FHIR implementations or future FHIR updates.The FHIR CG IG is an excellent step toward the interoperability of genetic lab test reports. However, it is a work-in-progress that needs informative and continuous input from the clinical genetics' community, specifically professional organizations, systems implementers, and genetic knowledgebase providers.

Physician-directed genetic screening to evaluate personal risk for medically actionable disorders: a large multi-center cohort study.

BACKGROUND: The use of proactive genetic screening for disease prevention and early detection is not yet widespread. Professional practice guidelines from the American College of Medical Genetics and Genomics (ACMG) have encouraged reporting pathogenic variants that confer personal risk for actionable monogenic hereditary disorders, but only as secondary findings from exome or genome sequencing. The Centers for Disease Control and Prevention (CDC) recognizes the potential public health impact of three Tier 1 actionable disorders. Here, we report results of a large multi-center cohort study to determine the yield and potential value of screening healthy individuals for variants associated with a broad range of actionable monogenic disorders, outside the context of secondary findings. METHODS: Eligible adults were offered a proactive genetic screening test by health care providers in a variety of clinical settings. The screening panel based on next-generation sequencing contained up to 147 genes associated with monogenic disorders within cancer, cardiovascular, and other important clinical areas. Sequence and intragenic copy number variants classified as pathogenic, likely pathogenic, pathogenic (low penetrance), or increased risk allele were considered clinically significant and reported. Results were analyzed by clinical area and severity/burden of disease using chi-square tests without Yates' correction. RESULTS: Among 10,478 unrelated adults screened, 1619 (15.5%) had results indicating personal risk for an actionable monogenic disorder. In contrast, only 3.1 to 5.2% had clinically reportable variants in genes suggested by the ACMG version 2 secondary findings list to be examined during exome or genome sequencing, and 2% had reportable variants related to CDC Tier 1 conditions. Among patients, 649 (6.2%) were positive for a genotype associated with a disease of high severity/burden, including hereditary cancer syndromes, cardiovascular disorders, or malignant hyperthermia susceptibility. CONCLUSIONS: This is one of the first real-world examples of specialists and primary care providers using genetic screening with a multi-gene panel to identify health risks in their patients. Nearly one in six individuals screened for variants associated with actionable monogenic disorders had clinically significant results. These findings provide a foundation for further studies to assess the role of genetic screening as part of regular medical care.

A qualitative investigation of biomedical informatics interoperability standards for genetic test reporting: benefits, challenges, and motivations from the testing laboratory's perspective.

PURPOSE: Genetic laboratory test reports can often be of limited computational utility to the receiving clinical information systems, such as clinical decision support systems. Many health-care interoperability (HC) standards aim to tackle this problem, but the perceived benefits, challenges, and motivations for implementing HC interoperability standards from the labs' perspective has not been systematically assessed. METHODS: We surveyed genetic testing labs across the United States and conducted a semistructured interview with responding lab representatives. We conducted a thematic analysis of the interview transcripts to identify relevant themes. A panel of experts discussed and validated the identified themes. RESULTS: Nine labs participated in the interview, and 24 relevant themes were identified within five domains. These themes included the challenge of complex and changing genetic knowledge, the motivation of competitive advantage, provided financial incentives, and the benefit of supporting the learning health system. CONCLUSION: Our study identified the labs' perspective on various aspects of implementing HC interoperability standards in producing and communicating genetic test reports. Interviewees frequently reported that increased adoption of HC standards may be motivated by competition and programs incentivizing and regulating the incorporation of interoperability standards for genetic test data, which could benefit quality control, research, and other areas.

A qualitative study of prevalent laboratory information systems and data communication patterns for genetic test reporting.

PURPOSE: The availability of genetic test data within the electronic health record (EHR) is a pillar of the US vision for an interoperable health IT infrastructure and a learning health system. Although EHRs have been highly investigated, evaluation of the information systems used by the genetic labs has received less attention-but is necessary for achieving optimal interoperability. This study aimed to characterize how US genetic testing labs handle their information processing tasks. METHODS: We followed a qualitative research method that included interviewing lab representatives and a panel discussion to characterize the information flow models. RESULTS: Ten labs participated in the study. We identified three generic lab system models and their relevant characteristics: a backbone system with additional specialized systems for interpreting genetic results, a brokering system that handles housekeeping and communication, and a single primary system for results interpretation and report generation. CONCLUSION: Labs have heterogeneous workflows and generally have a low adoption of standards when sending genetic test reports back to EHRs. Core interpretations are often delivered as free text, limiting their computational availability for clinical decision support tools. Increased provision of genetic test data in discrete and standard-based formats by labs will benefit individual and public health.

Myocardial overexpression of ANKRD1 causes sinus venosus defects and progressive diastolic dysfunction.

AIMS: Increased Ankyrin Repeat Domain 1 (ANKRD1) levels linked to gain of function mutations have been associated to total anomalous pulmonary venous return and adult cardiomyopathy occurrence in humans. The link between increased ANKRD1 level and cardiac structural and functional disease is not understood. To get insight into this problem, we have generated a gain of function ANKRD1 mouse model by overexpressing ANKRD1 in the myocardium. METHODS AND RESULTS: Ankrd1 is expressed non-homogeneously in the embryonic myocardium, with a dynamic nucleo-sarcomeric localization in developing cardiomyocytes. ANKRD1 transgenic mice present sinus venosus defect, which originates during development by impaired remodelling of early embryonic heart. Adult transgenic hearts develop diastolic dysfunction with preserved ejection fraction, which progressively evolves into heart failure, as shown histologically and haemodynamically. Transgenic cardiomyocyte structure, sarcomeric assembly, and stability are progressively impaired from embryonic to adult life. Postnatal transgenic myofibrils also present characteristic functional alterations: impaired compliance at neonatal stage and impaired lusitropism in adult hearts. Altogether, our combined analyses suggest that impaired embryonic remodelling and adult heart dysfunction in ANKRD1 transgenic mice present a common ground of initial cardiomyocyte defects, which are exacerbated postnatally. Molecular analysis showed transient activation of GATA4-Nkx2.5 transcription in early transgenic embryos and subsequent dynamic transcriptional modulation within titin gene. CONCLUSIONS: ANKRD1 is a fine mediator of cardiomyocyte response to haemodynamic load in the developing and adult heart. Increased ANKRD1 levels are sufficient to initiate an altered cellular phenotype, which is progressively exacerbated into a pathological organ response by the high ventricular workload during postnatal life. Our study defines for the first time a unifying picture for ANKRD1 role in heart development and disease and provides the first mechanistic link between ANKRD1 overexpression and cardiac disease onset.

Targeted gene panel sequencing for the rapid diagnosis of acutely ill infants.

BACKGROUND: Exome/genome sequencing (ES/GS) have been recently used in neonatal and pediatric/cardiac intensive care units (NICU and PICU/CICU) to diagnose and care for acutely ill infants, but the effectiveness of targeted gene panels for these purposes remains unknown. METHODS: RapSeq, a newly developed panel targeting 4,503 disease-causing genes, was employed on selected patients in our NICU/PICU/CICU. Twenty trios were sequenced from October 2015 to March 2017. We assessed diagnostic yield, turnaround times, and clinical consequences. RESULTS: A diagnosis was made in 10/20 neonates (50%); eight had de novo variants (ASXL1, CHD, FBN1, KMT2D, FANCB, FLNA, PAX3), one was a compound heterozygote for CHAT, and one had a maternally inherited GNAS variant. Preliminary reports were generated by 9.6 days (mean); final reports after Sanger sequencing at 16.3 days (mean). In all positive infants, the diagnosis changed management. In a case with congenital myasthenia, diagnosis and treatment occurred at 17 days versus 7 months in a historical control. CONCLUSIONS: This study shows that a gene panel that includes the majority of known disease-causing genes can rapidly identify a diagnosis in a large number of tested infants. Due to simpler deployment and interpretation and lower costs, this approach might represent an alternative to ES/GS in the NICU/PICU/CICU.

Expanding the genetic and clinical spectrum of the NONO-associated X-linked intellectual disability syndrome.

The NONO gene encodes a nuclear protein involved in RNA metabolism. Hemizygous loss-of-function NONO variants have been associated with syndromic intellectual disability and with left ventricular noncompaction (LVNC). A two-year-old boy presented to the University of Utah's Penelope Undiagnosed Disease Program with developmental delay, nonfamilial features, relative macrocephaly, and dilated cardiomyopathy with LVNC and Ebstein anomaly. Brain MRI showed a thick corpus callosum, mild Chiari I malformation, and a flattened pituitary. Exome sequencing identified a novel intronic deletion (c.154+5_154+6delGT) in the NONO gene. Splicing studies demonstrated intron 4 read-through and the use of an alternative donor causing the frameshift p.Asn52Serfs*6. Family segregation analysis showed that the variant occurred de novo in the boy's unaffected mother. MRI and endocrine findings suggest that hypopituitarism may contribute to growth failure, abnormal thyroid hormone levels, cryptorchidism, or delayed puberty in patients with NONO-associated disease. Also, including this case LVNC has been observed in five out of eight patients, and this report also confirms an association between loss of NONO and Ebstein anomaly. In some cases, unrelated individuals share the same pathogenic NONO variants but do not all have clinically significant LVNC, suggesting that additional modifiers may contribute to cardiac phenotypes.

DMD mutation and LTBP4 haplotype do not predict onset of left ventricular dysfunction in Duchenne muscular dystrophy.

Cardiomyopathy develops in >90% of Duchenne muscular dystrophy (DMD) patients by the second decade of life. We assessed the associations between DMD gene mutations, as well as Latent transforming growth factor-beta-binding protein 4 (LTBP4) haplotypes, and age at onset of myocardial dysfunction in DMD. DMD patients with baseline normal left ventricular systolic function and genotyping between 2004 and 2013 were included. Patients were grouped in multiple ways: specific DMD mutation domains, true loss-of-function mutations (group A) versus possible residual gene expression (group B), and LTBP4 haplotype. Age at onset of myocardial dysfunction was the first echocardiogram with an ejection fraction <55% and/or shortening fraction <28%. Of 101 DMD patients, 40 developed cardiomyopathy. There was no difference in age at onset of myocardial dysfunction among DMD genotype mutation domains (13.7±4.8 versus 14.3±1.0 versus 14.3±2.9 versus 13.8±2.5, p=0.97), groups A and B (14.4±2.8 versus 12.1±4.4, p=0.09), or LTBP4 haplotypes (14.5±3.2 versus 13.1±3.2 versus 11.0±2.8, p=0.18). DMD gene mutations involving the hinge 3 region, actin-binding domain, and exons 45-49, as well as the LTBP4 IAAM haplotype, were not associated with age of left ventricular dysfunction onset in DMD.

Use of Extracorporeal Membrane Oxygenation and Mortality in Pediatric Cardiac Surgery Patients With Genetic Conditions: A Multicenter Analysis.

OBJECTIVE: Congenital heart disease is commonly a manifestation of genetic conditions. Surgery and/or extracorporeal membrane oxygenation were withheld in the past from some patients with genetic conditions. We hypothesized that surgical care of children with genetic conditions has increased over the last decade, but their cardiac extracorporeal membrane oxygenation use remains lower and mortality greater. DESIGN: Retrospective cohort study. SETTING: Patients admitted to the Pediatric Health Information System database 18 years old or younger with cardiac surgery during 2003-2014. Genetic conditions identified by International Classification of Diseases, 9th Edition codes were grouped as follows: trisomy 21, trisomy 13 or 18, 22q11 deletion, and all "other" genetic conditions and compared with patients without genetic condition. PATIENTS: A total of 95,253 patients met study criteria, no genetic conditions (85%), trisomy 21 (10%), trisomy 13 or 18 (0.2%), 22q11 deletion (1%), and others (5%). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Annual surgical cases did not vary over time. Compared to patients without genetic conditions, trisomy 21 patients, extracorporeal membrane oxygenation use was just over half (odds ratio, 0.54), but mortality with and without extracorporeal membrane oxygenation were similar. In trisomy 13 or 18 patients, extracorporeal membrane oxygenation use was similar to those without genetic condition, but all five treated with extracorporeal membrane oxygenation died. 22q11 patients compared with those without genetic condition had similar extracorporeal membrane oxygenation use, but greater odds of extracorporeal membrane oxygenation mortality (odds ratio, 3.44). Other genetic conditions had significantly greater extracorporeal membrane oxygenation use (odds ratio, 1.22), mortality with extracorporeal membrane oxygenation (odds ratio, 1.42), and even greater mortality odds without (odds ratio, 2.62). CONCLUSIONS: The proportion of children undergoing cardiac surgery who have genetic conditions did not increase during the study. Excluding trisomy 13 or 18, all groups of genetic conditions received and benefited from extracorporeal membrane oxygenation, although extracorporeal membrane oxygenation mortality was greater for those with 22q11 deletion and other genetic conditions.

Experience with Integrating Diagnostic Decision Support Software with Electronic Health Records: Benefits versus Risks of Information Sharing.

INTRODUCTION: Reducing misdiagnosis has long been a goal of medical informatics. Current thinking has focused on achieving this goal by integrating diagnostic decision support into electronic health records. METHODS: A diagnostic decision support system already in clinical use was integrated into electronic health record systems at two large health systems, after clinician input on desired capabilities. The decision support provided three outputs: editable text for use in a clinical note, a summary including the suggested differential diagnosis with a graphical representation of probability, and a list of pertinent positive and pertinent negative findings (with onsets). RESULTS: Structured interviews showed widespread agreement that the tool was useful and that the integration improved workflow. There was disagreement among various specialties over the risks versus benefits of documenting intermediate diagnostic thinking. Benefits were most valued by specialists involved in diagnostic testing, who were able to use the additional clinical context for richer interpretation of test results. Risks were most cited by physicians making clinical diagnoses, who expressed concern that a process that generated diagnostic possibilities exposed them to legal liability. DISCUSSION AND CONCLUSION: Reconciling the preferences of the various groups could include saving only the finding list as a patient-wide resource, saving intermediate diagnostic thinking only temporarily, or adoption of professional guidelines to clarify the role of decision support in diagnosis.

Turner Syndrome in Girls Presenting with Coarctation of the Aorta.

OBJECTIVE: To evaluate the frequency of Turner syndrome in a population-based, statewide cohort of girls with coarctation of the aorta. STUDY DESIGN: The Utah Birth Defects Network was used to ascertain a cohort of girls between 1997 and 2011 with coarctation of the aorta. Livebirths with isolated coarctation of the aorta or transverse arch hypoplasia were included and patients with complex congenital heart disease not usually seen in Turner syndrome were excluded. RESULTS: Of 244 girls with coarctation of the aorta, 77 patients were excluded, leaving a cohort of 167 girls; 86 patients (51%) had chromosomal studies and 21 (12.6%) were diagnosed with Turner syndrome. All patients were diagnosed within the first 4 months of life and 5 (24%) were diagnosed prenatally. Fifteen patients (71%) had Turner syndrome-related findings in addition to coarctation of the aorta. Girls with mosaicism were less likely to have Turner syndrome-associated findings (3/6 mosaic girls compared with 12/17 girls with non-mosaic 45,X). Twelve girls (57%) diagnosed with Turner syndrome also had a bicommissural aortic valve. CONCLUSION: At least 12.6% of girls born with coarctation of the aorta have karyotype-confirmed Turner syndrome. Such a high frequency, combined with the clinical benefits of an early diagnosis, supports genetic screening for Turner syndrome in girls presenting with coarctation of the aorta.

Exome analysis of a family with Wolff-Parkinson-White syndrome identifies a novel disease locus.

Wolff-Parkinson-White (WPW) syndrome is a common cause of supraventricular tachycardia that carries a risk of sudden cardiac death. To date, mutations in only one gene, PRKAG2, which encodes the 5'-AMP-activated protein kinase subunit γ-2, have been identified as causative for WPW. DNA samples from five members of a family with WPW were analyzed by exome sequencing. We applied recently designed prioritization strategies (VAAST/pedigree VAAST) coupled with an ontology-based algorithm (Phevor) that reduced the number of potentially damaging variants to 10: a variant in KCNE2 previously associated with Long QT syndrome was also identified. Of these 11 variants, only MYH6 p.E1885K segregated with the WPW phenotype in all affected individuals and was absent in 10 unaffected family members. This variant was predicted to be damaging by in silico methods and is not present in the 1,000 genome and NHLBI exome sequencing project databases. Screening of a replication cohort of 47 unrelated WPW patients did not identify other likely causative variants in PRKAG2 or MYH6. MYH6 variants have been identified in patients with atrial septal defects, cardiomyopathies, and sick sinus syndrome. Our data highlight the pleiotropic nature of phenotypes associated with defects in this gene.

Shared Segment Analysis and Next-Generation Sequencing Implicates the Retinoic Acid Signaling Pathway in Total Anomalous Pulmonary Venous Return (TAPVR).

Most isolated congenital heart defects are thought to be sporadic and are often ascribed to multifactorial mechanisms with poorly understood genetics. Total Anomalous Pulmonary Venous Return (TAPVR) occurs in 1 in 15,000 live-born infants and occurs either in isolation or as part of a syndrome involving aberrant left-right development. Previously, we reported causative links between TAVPR and the PDGFRA gene. TAPVR has also been linked to the ANKRD1/CARP genes. However, these genes only explain a small fraction of the heritability of the condition. By examination of phased single nucleotide polymorphism genotype data from 5 distantly related TAPVR patients we identified a single 25 cM shared, Identical by Descent genomic segment on the short arm of chromosome 12 shared by 3 of the patients and their obligate-carrier parents. Whole genome sequence (WGS) analysis identified a non-synonymous variant within the shared segment in the retinol binding protein 5 (RBP5) gene. The RBP5 variant is predicted to be deleterious and is overrepresented in the TAPVR population. Gene expression and functional analysis of the zebrafish orthologue, rbp7, supports the notion that RBP5 is a TAPVR susceptibility gene. Additional sequence analysis also uncovered deleterious variants in genes associated with retinoic acid signaling, including NODAL and retinol dehydrogenase 10. These data indicate that genetic variation in the retinoic acid signaling pathway confers, in part, susceptibility to TAPVR.

Progressive Aortic Dilation Associated With ACTA2 Mutations Presenting in Infancy.

Mutations in the gene ACTA2 are a recognized cause of aortic aneurysms with aortic dissection in adulthood. Recently, a specific mutation (Arg179His) in this gene has been associated with multisystem smooth muscle dysfunction presenting in childhood. We describe 3 patients with an R179H mutation, all of whom presented with an aneurysmal patent ductus arteriosus. Detailed information on the rate of aortic disease progression throughout childhood is provided. Death or need for ascending aortic replacement occurred in all patients. Genetic testing for ACTA2 mutations should be considered in all infants presenting with ductal aneurysms.

Clinical utility of a next generation sequencing panel assay for Marfan and Marfan-like syndromes featuring aortopathy.

Aortopathy can be defined as aortic dilation, aneurysm, dissection, and tortuosity. Familial aortopathy may occur secondary to fibrillin-1 (FBN1) mutations in the setting of Marfan syndrome, or may occur as a result of other genetic defects with different, but occasionally overlapping, phenotypes. Because of the phenotypic overlap and genetic heterogeneity of disorders featuring aortopathy, we developed a next generation sequencing (NGS) assay and comparative genomic hybridization (CGH) array to detect mutations in 10 genes that cause thoracic aortic aneurysms (TAAs). Here, we report on the clinical and molecular findings in 175 individuals submitted for aortopathy panel testing at ARUP laboratories. Ten genes associated with heritable aortopathies were targeted using hybridization capture prior to sequencing. NGS results were analyzed, and variants were confirmed using Sanger sequencing. Array CGH was used to detect copy-number variation. Of 175 individuals, 18 had a pathogenic mutation and 32 had a variant of uncertain significance (VUS). Most pathogenic mutations (72%) were identified in FBN1. A novel large SMAD3 duplication and FBN1 deletion were identified. Over half who had TAAs or other aortic involvement tested negative for a mutation, suggesting that additional aortopathy genes exist. We anticipate that the clinical sensitivity of at least 10.3% will rise with VUS reclassification and as additional genes are identified and included in the panel. The aortopathy NGS panel aids in the timely molecular diagnosis of individuals with disorders featuring aortopathy and guides proper treatment.

Rationale for the Cytogenomics of Cardiovascular Malformations Consortium: A Phenotype Intensive Registry Based Approach.

Cardiovascular malformations (CVMs) are the most common birth defect, occurring in 1%-5% of all live births. Although the genetic contribution to CVMs is well recognized, the genetic causes of human CVMs are identified infrequently. In addition, a failure of systematic deep phenotyping of CVMs, resulting from the complexity and heterogeneity of malformations, has obscured genotype-phenotype correlations and contributed to a lack of understanding of disease mechanisms. To address these knowledge gaps, we have developed the Cytogenomics of Cardiovascular Malformations (CCVM) Consortium, a multi-site alliance of geneticists and cardiologists, contributing to a database registry of submicroscopic genetic copy number variants (CNVs) based on clinical chromosome microarray testing in individuals with CVMs using detailed classification schemes. Cardiac classification is performed using a modification to the National Birth Defects Prevention Study approach, and non-cardiac diagnoses are captured through ICD-9 and ICD-10 codes. By combining a comprehensive approach to clinically relevant genetic analyses with precise phenotyping, the Consortium goal is to identify novel genomic regions that cause or increase susceptibility to CVMs and to correlate the findings with clinical phenotype. This registry will provide critical insights into genetic architecture, facilitate genotype-phenotype correlations, and provide a valuable resource for the medical community.

Clinical exome sequencing identifies a novel TUBB4A mutation in a child with static hypomyelinating leukodystrophy.

BACKGROUND: Leukodystrophies are a large group of inherited diseases of central nervous system myelin. There are few treatments, and most patients do not receive a final genetic diagnosis. PATIENT: We report a novel presentation of a female child with hypotonia, global developmental delay, and rotatory nystagmus. Brain MRI demonstrated profound hypomyelination and minimal or no atrophy in the brain stem or cerebellum. RESULTS: Extensive testing failed to yield a diagnosis until clinical whole-exome sequencing revealed a novel pathogenic mutation in the ß-tubulin gene TUBB4A. TUBB4A is a cause of hereditary dystonia type 4 and has recently been reported to cause hypomyelination with atrophy of the basal ganglia and cerebellum. CONCLUSIONS: This report expands the phenotypic spectrum of TUBB4A-associated neurological diseases to include static hypomyelinating leukodystrophy and supports the clinical relevance of next-generation sequencing diagnosis approaches.