Bicuspid Aortic Valve Disease With Early Onset Complications: Characteristics And Aortic Outcomes.

Bicuspid aortic valve (BAV) is the most common congenital heart malformation in adults but can also cause childhood-onset complications. In multicenter study, we found that adults who experience significant complications of BAV disease before age 30 are distinguished from the majority of BAV cases that manifest after age 50 by a relatively severe clinical course, with higher rates of surgical interventions, more frequent second interventions, and a greater burden of congenital heart malformations. These observations highlight the need for prompt recognition, regular lifelong surveillance, and targeted interventions to address the significant health burdens of patients with early onset BAV complications.

Generation and characterization of a human induced pluripotent stem cell (iPSC) line from a patient with congenital heart disease (CHD).

Epstein-Barr virus (EBV) immortalized lymphoblastoid cell lines (LCLs) are widely used for banking. This bioresource could be leveraged for creating human iPSC lines to model diseases including CHD. We generated an LCL-derived iPSC line (NCHi001-A) from a patient with congenital aortic valve stenosis. NCHi001-A was EBV and transgenes free, exhibited stem cell-like morphology, expressed pluripotency markers, has a normal karyotype, and could be differentiated into cells of three germ layers in vitro. Relationship inference via a microarray-based analysis showed NCHi001-A is identical to the parental cell line. NCHi001-A can be used for disease modeling, drug discovery, and cell therapy development.

A Decade's Experience in Pediatric Chromosomal Microarray Reveals Distinct Characteristics Across Ordering Specialties.

Chromosomal microarray (CMA) is a testing modality frequently used in pediatric patients; however, published data on its utilization are limited to the genetic setting. We performed a database search for all CMA testing performed from 2010 to 2020, and delineated the diagnostic yield based on patient characteristics, including sex, age, clinical specialty of providers, indication of testing, and pathogenic finding. The indications for testing were further categorized into Human Phenotype Ontology categories for analysis. This study included a cohort of 14,541 patients from 29 different medical specialties, of whom 30% were from the genetics clinic. The clinical indications for testing suggested that neonatology patients demonstrated the greatest involvement of multiorgan systems, involving the most Human Phenotype Ontology categories, compared with developmental behavioral pediatrics and neurology patients being the least. The top pathogenic findings for each specialty differed, likely due to the varying clinical features and indications for testing. Deletions involving the 22q11.21 locus were the top pathogenic findings for patients presenting to genetics, neonatology, cardiology, and surgery. Our data represent the largest pediatric cohort published to date. This study is the first to demonstrate the diagnostic utility of this assay for patients seen in the setting of different specialties, and it provides normative data of CMA results among a general pediatric population referred for testing because of variable clinical presentations.

Common deletion variants causing protocadherin-α deficiency contribute to the complex genetics of BAV and left-sided congenital heart disease.

Bicuspid aortic valve (BAV) with ~1%-2% prevalence is the most common congenital heart defect (CHD). It frequently results in valve disease and aorta dilation and is a major cause of adult cardiac surgery. BAV is genetically linked to rare left-heart obstructions (left ventricular outflow tract obstructions [LVOTOs]), including hypoplastic left heart syndrome (HLHS) and coarctation of the aorta (CoA). Mouse and human studies indicate LVOTO is genetically heterogeneous with a complex genetic etiology. Homozygous mutation in the Pcdha protocadherin gene cluster in mice can cause BAV, and also HLHS and other LVOTO phenotypes when accompanied by a second mutation. Here we show two common deletion copy number variants (delCNVs) within the PCDHA gene cluster are associated with LVOTO. Analysis of 1,218 white individuals with LVOTO versus 463 disease-free local control individuals yielded odds ratios (ORs) at 1.47 (95% confidence interval [CI], 1.13-1.92; p = 4.2 × 10-3) for LVOTO, 1.47 (95% CI, 1.10-1.97; p = 0.01) for BAV, 6.13 (95% CI, 2.75-13.7; p = 9.7 × 10-6) for CoA, and 1.49 (95% CI, 1.07-2.08; p = 0.019) for HLHS. Increased OR was observed for all LVOTO phenotypes in homozygous or compound heterozygous PCDHA delCNV genotype comparison versus wild type. Analysis of an independent white cohort (381 affected individuals, 1,352 control individuals) replicated the PCDHA delCNV association with LVOTO. Generalizability of these findings is suggested by similar observations in Black and Chinese individuals with LVOTO. Analysis of Pcdha mutant mice showed reduced PCDHA expression at regions of cell-cell contact in aortic smooth muscle and cushion mesenchyme, suggesting potential mechanisms for BAV pathogenesis and aortopathy. Together, these findings indicate common variants causing PCDHA deficiency play a significant role in the genetic etiology of common and rare LVOTO-CHD.

Hypomorphic alleles pose challenges in rare disease genomic variant interpretation.

Exon skipping associated with an ATP7B intronic variant in a patient with Wilson's disease. (A) Sashimi plot visualization of aligned RNA sequencing data from proband liver tissue at ATP7B exons 14-13-12. The red track shows traditional RNA-seq data; the blue track shows RNA-seq enriched with exon capture (cDNA-cap) which achieves higher depth of protein-coding transcripts. The histogram indicates overall sequencing depth while arcs tabulate the number of junction-spanning reads supporting exon pairs. (B) The domain structure (top) and exon structure (bottom) of ATP7B. Loss of exon 13 (dashed box) would remove a transmembrane domain and disrupt the first phosphorylation domain.

Update in the Mucopolysaccharidoses.

The mucopolysaccharidoses (MPS) are a genetically heterogenous group of enzyme deficiencies marked by accumulation of glycosaminoglycans in lysosomes leading to multisystem disease. Although significant therapeutic advances have been made for the MPS disorders, including recombinant enzyme replacement approaches, the neuronopathic features of MPS lack adequate treatment. Gene therapies, including adeno-associated virus vectors targeting the central nervous system, hold significant promise for this group of disorders. Optimal outcomes of all therapies will require early disease identification and treatment, ideally by newborn screening.

Novel frameshift variant in MYL2 reveals molecular differences between dominant and recessive forms of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is characterized by thickening of the ventricular muscle without dilation and is often associated with dominant pathogenic variants in cardiac sarcomeric protein genes. Here, we report a family with two infants diagnosed with infantile-onset HCM and mitral valve dysplasia that led to death before one year of age. Using exome sequencing, we discovered that one of the affected children had a homozygous frameshift variant in Myosin light chain 2 (MYL2:NM_000432.3:c.431_432delCT: p.Pro144Argfs*57;MYL2-fs), which alters the last 20 amino acids of the protein and is predicted to impact the most C-terminal of the three EF-hand domains in MYL2. The parents are unaffected heterozygous carriers of the variant and the variant is absent in control cohorts from gnomAD. The absence of the phenotype in carriers and the infantile presentation of severe HCM is in contrast to HCM associated with dominant MYL2 variants. Immunohistochemical analysis of the ventricular muscle of the deceased patient with the MYL2-fs variant showed a marked reduction of MYL2 expression compared to an unaffected control. In vitro overexpression studies further indicate that the MYL2-fs variant is actively degraded. In contrast, an HCM-associated missense variant (MYL2:p.Gly162Arg) and three other MYL2 stop-gain variants (p.E22*, p.K62*, p.E97*) that result in loss of the EF domains are stably expressed but show impaired localization. The degradation of the MYL2-fs can be rescued by inhibiting the cell's proteasome function supporting a post-translational effect of the variant. In vivo rescue experiments with a Drosophila MYL2-homolog (Mlc2) knockdown model indicate that neither the MYL2-fs nor the MYL2:p.Gly162Arg variant supports normal cardiac function. The tools that we have generated provide a rapid screening platform for functional assessment of variants of unknown significance in MYL2. Our study supports an autosomal recessive model of inheritance for MYL2 loss-of-function variants in infantile HCM and highlights the variant-specific molecular differences found in MYL2-associated cardiomyopathy.

Novel in-frame FLNB deletion causes Larsen syndrome in a three-generation pedigree.

A 4-yr-old female with congenital knee dislocations and joint laxity was noted to have a strong maternal family history comprising multiple individuals with knee problems and clubfeet. As the knee issues were the predominant clinical features, clinical testing included sequencing of LMX1B, TBX2, and TBX4, which identified no significant variants. Research genome sequencing was performed in the proband, parents, and maternal grandfather. A heterozygous in-frame deletion in FLNB c. 5468_5470delAGG, which predicts p.(Glu1823del), segregated with the disease. The variant is rare in the gnomAD database, removes a residue that is evolutionarily conserved, and is predicted to alter protein length. Larsen syndrome may present with pathology that primarily involves one joint and thus may be difficult to differentiate clinically from other skeletal dysplasias or arthrogryposis syndromes. The p.(Glu1823del) variant maps to a filamin repeat domain where other disease-causing variants are clustered, consistent with a probable gain-of-function mechanism. It has reportedly been observed in two individuals in the gnomAD database, suggesting that mild presentations of Larsen syndrome, like the individual reported here, may be underdiagnosed in the general population.

Expansion of B4GALT7 linkeropathy phenotype to include perinatal lethal skeletal dysplasia.

Proteoglycans have a core polypeptide connected to glycosaminoglycans (GAGs) via a common tetrasaccharide linker region. Defects in enzymes that synthesize the linker result in a group of autosomal recessive conditions called "linkeropathies". Disease manifests with skeletal and connective tissue features, including short stature, hyperextensible skin, and joint hypermobility. We report a family with three affected pregnancies showing short limbs, cystic hygroma, and perinatal death. Two spontaneously aborted; one survived 1 day after term delivery, and had short limbs, bell-shaped thorax, 11 ribs, absent thumbs, and cleft palate. Exome sequencing of the proband and one affected fetus identified compound heterozygous missense variants, NM_007255.3: c.808C>T (p.(Arg270Cys)) and NM_007255.3: c.398A>G (p.(Gln133Arg)), in B4GALT7, a gene required for GAG linker biosynthesis. Homozygosity for p.(Arg270Cys), associated with partial loss of B4GALT7 function, causes Larsen of Reunion Island syndrome (LRS), however no previous studies have linked p.(Gln133Arg) to disease. The p.(Gln133Arg) and p.(Arg270Cys) variants were transfected into CHO pgsB-618 cells. High protein expression of p.(Gln133Arg) was found, with mislocalization, compared to p.(Arg270Cys) that had a normal Golgi-like pattern. The p.(Gln133Arg) had almost no enzyme activity and little production of heparan sulfate GAGs, while p.(Arg270Cys) only had 17% of wild-type activity. These findings expand the phenotype of B4GALT7-related linkeropathies to include lethal skeletal dysplasia due to more severe loss of function.

Genetic evaluation of cardiomyopathy: a clinical practice resource of the American College of Medical Genetics and Genomics (ACMG).

PURPOSE: The purpose of this document is to provide updated guidance for the genetic evaluation of cardiomyopathy and for an approach to manage secondary findings from cardiomyopathy genes. The genetic bases of the primary cardiomyopathies (dilated, hypertrophic, arrhythmogenic right ventricular, and restrictive) have been established, and each is medically actionable; in most cases established treatments or interventions are available to improve survival, reduce morbidity, and enhance quality of life. METHODS: A writing group of cardiologists and genetics professionals updated guidance, first published in 2009 for the Heart Failure Society of America (HFSA), in a collaboration with the American College of Medical Genetics and Genomics (ACMG). Each recommendation was assigned to teams of individuals by expertise, literature was reviewed, and recommendations were decided by consensus of the writing group. Recommendations for family history, phenotype screening of at-risk family members, referral to expert centers as needed, genetic counseling, and cardiovascular therapies, informed in part by phenotype, are presented in the HFSA document. RESULTS: A genetic evaluation of cardiomyopathy is indicated with a cardiomyopathy diagnosis, which includes genetic testing. Guidance is also provided for clinical approaches to secondary findings from cardiomyopathy genes. This is relevant as cardiomyopathy is the phenotype associated with 27% of the genes on the ACMG list for return of secondary findings. Recommendations herein are considered expert opinion per current ACMG policy as no systematic approach to literature review was conducted. CONCLUSION: Genetic testing is indicated for cardiomyopathy to assist in patient care and management of at-risk family members.

Differential Prevalence of Antibodies Against Adeno-Associated Virus in Healthy Children and Patients with Mucopolysaccharidosis III: Perspective for AAV-Mediated Gene Therapy.

Recombinant adeno-associated virus (AAV) vectors are promising gene therapy tools. However, pre-existing antibodies (Abs) to many useful AAV serotypes pose a critical challenge for the translation of gene therapies. As part of AAV gene therapy program for treating mucopolysaccharidosis (MPS) III patients, the seroprevalence profiles of AAV1-9 and rh74 were investigated in MPS IIIA/IIIB patients and in healthy children. Using enzyme-linked immunosorbent assay for αAAV-IgG, significantly higher seroprevalence was observed for AAV1 and AAVrh74 in 2- to 7-year-old MPS III patients than in healthy controls. Seroprevalence for the majority of tested AAV serotypes appears to peak before 8 years of age in MPS III subjects, with the exception of increases in αAAV8 and αAAV9 Abs in 8- to 19-year-old MPS IIIA patients. In contrast, significant increases in seroprevalence were observed for virtually all tested AAV serotypes in 8- to 15-year-old healthy children compared to 2- to 7-year-olds. Co-prevalence and Ab level correlation results followed the previously established divergence-based clade positions of AAV1-9. Interestingly, the individuals positive for αAAVrh74-Abs showed the lowest co-prevalence with Abs for AAV1-9 (22-40%). However, all or nearly all (77-100%) of subjects who were seropositive for any of serotypes 1-9 were also positive for αAAVrh74-IgG. Notably, the majority (78%) of αAAV seropositive individuals were also Ab-positive for one to five of the tested AAV serotypes, mostly with low levels of αAAV-Abs (1:50-100), while a minority (22%) were seropositive for six or more AAV serotypes, mostly with high levels of αAAV-IgG for multiple serotypes. In general, the highest IgG levels were reactive to AAV2, AAV3, and AAVrh74. The data illustrate the complex seroprevalence profiles of AAV1-9 and rh74 in MPS patients and healthy children, indicating the potential association of AAV seroprevalence with age and disease conditions. The broad co-prevalence of Abs for different AAV serotypes reinforces the challenge of pre-existing αAAV-Abs for translating AAV gene therapy to clinical applications, regardless of the vector serotype.

Abnormal Longitudinal Growth of the Aorta in Children with Familial Bicuspid Aortic Valve.

Bicuspid aortic valve (BAV) is the most common type of congenital heart defect (CHD) and is associated with clinically significant cardiovascular complications including valve calcification and ascending aortopathy (AscAo), predominantly occurring in adulthood. While a limited number of genetic etiologies for BAV have been defined, family members of affected individuals display BAV along with other left-sided CHD. This has led to guidelines from the American Heart Association and American College of Cardiology that recommend echocardiographic screening of first-degree relatives of affected adults. While potentially beneficial in adults, the yield of such screening in children is unknown. The purpose of this study was to investigate a cohort of children with familial BAV to determine the frequency of development of AscAo, and to identify risk factors that contribute to abnormal aortic growth. Echocardiograms over a 10-year follow-up period were reviewed on 26 patients with familial BAV [22 male, 4 female; 22 with isolated BAV, 6 with BAV and aortic coarctation (CoA)]. All had a family history of CHD and were recruited from 2005 to 2010 as part of a genetics research study. Four aortic segments (annulus, root, sinotubular junction, ascending aorta) on parasternal long-axis echocardiographic images were measured by a single observer. The mean age at first echocardiogram was 7.1 ± 5.5 and that was 13.8 ± 6.2 years at the last echocardiogram. Only patients with > 2 echocardiograms in the 10-year period were included. Z score measurements of the aorta were plotted over time and based on these the cohort was divided into two groups: Group 1 (abnormal)-Z score for any segment > 2 or a change in Z score > 2 over follow-up; Group 2 (normal)-Z score < 2 throughout follow-up and change in Z score < 2. Nineteen out of 26 children displayed abnormal aortic growth or dilation of the aorta. BAV with right/left cusp fusion was more frequent in Group 1 (15/18) versus Group 2 (3/7) (p < 0.05). There were no significant differences in gender, aortic valve dysfunction, presence of CoA, family history, cardiac function, presence of left ventricular hypertrophy, or medication use between the 2 groups. In our longitudinal study of children with familial BAV, the majority display evidence of abnormal growth of the ascending aorta during the follow-up period consistent with AscAo and support the extension of current adult guidelines to the pediatric population. While we find that right/left cusp fusion is a risk factor for abnormal aortic growth, additional studies are needed to identify other factors to better select children who require serial screening.

A cohort study of multiple families with FBN1 p.R650C variant, ectopia lentis, and low but not absent risk for aortopathy.

Marfan syndrome is a multisystem disease with cardiovascular, ophthalmologic, and skeletal features. Diagnosis is made clinically with emphasis on presence of aortic root dilation and ectopia lentis (EL). Most individuals meeting these criteria have a pathogenic variant in FBN1, usually unique or observed rarely. Individuals with EL alone may also have FBN1 pathogenic variants, and the risk for aortic disease is not well known. We identified a unique cohort of 31 individuals (mean age 29, range 2-78) from nine families ascertained by a proband with EL alone, who had the same FBN1 p.R650C variant. Comparison was made to individuals with Marfan syndrome (n = 103 from 97 families) at our institution. Those with the p.R650C variant had few skeletal features of Marfan syndrome. Age of onset of EL was later compared to others with cysteine variant changes. Aortic root dilation occurred in 4/16 (25%) of the p.R650C group versus 71/83 (86%) in the comparator group (p < 0.001) and dissection or replacement in 1/31 (3%) versus 20/103 (19%; p < 0.04). Aortic root Z scores were much lower in the p.R650C (0.34 ± 1.70) versus the comparator (2.99 ± 2.54; p < 0.0002). Kaplan-Meier failure curves for aortic root dilation demonstrated later age of onset and differed significantly for incidence rate ratio (comparator vs. p.R650C = 5.35, CI 1.84-21.17; p = 0.0001). Individuals with p.R650C predominantly have EL, but do have risk for aortic dilation at ages later than typical for Marfan syndrome in general and for cysteine changes specifically. Surveillance for aortic dilation is required but may occur less frequently.

Utilization of Whole Exome Sequencing to Identify Causative Mutations in Familial Congenital Heart Disease.

BACKGROUND: Congenital heart disease (CHD) is the most common type of birth defect with family- and population-based studies supporting a strong genetic cause for CHD. The goal of this study was to determine whether a whole exome sequencing (WES) approach could identify pathogenic-segregating variants in multiplex CHD families. METHODS AND RESULTS: WES was performed on 9 kindreds with familial CHD, 4 with atrial septal defects, 2 with patent ductus arteriosus, 2 with tetralogy of Fallot, and 1 with pulmonary valve dysplasia. Rare variants (<1% minor allele frequency) that segregated with disease were identified by WES, and variants in 69 CHD candidate genes were further analyzed. These selected variants were subjected to in silico analysis to predict pathogenicity and resulted in the discovery of likely pathogenic mutations in 3 of 9 (33%) families. A GATA4 mutation in the transactivation domain, p.G115W, was identified in familial atrial septal defects and demonstrated decreased transactivation ability in vitro. A p.I263V mutation in TLL1 was identified in an atrial septal defects kindred and is predicted to affect the enzymatic functionality of TLL1. A disease-segregating splice donor site mutation in MYH11 (c.4599+1delG) was identified in familial patent ductus arteriosus and found to disrupt normal splicing of MYH11 mRNA in the affected individual. CONCLUSIONS: Our findings demonstrate the clinical utility of WES to identify causative mutations in familial CHD and demonstrate the successful use of a CHD candidate gene list to allow for a more streamlined approach enabling rapid prioritization and identification of likely pathogenic variants from large WES data sets. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT0112048.

A GLP-Compliant Toxicology and Biodistribution Study: Systemic Delivery of an rAAV9 Vector for the Treatment of Mucopolysaccharidosis IIIB.

No treatment is currently available for mucopolysaccharidosis (MPS) IIIB, a neuropathic lysosomal storage disease due to defect in α-N-acetylglucosaminidase (NAGLU). In preparation for a clinical trial, we performed an IND-enabling GLP-toxicology study to assess systemic rAAV9-CMV-hNAGLU gene delivery in WT C57BL/6 mice at 1 × 10(14) vg/kg and 2 × 10(14) vg/kg (n = 30/group, M:F = 1:1), and non-GLP testing in MPS IIIB mice at 2 × 10(14) vg/kg. Importantly, no adverse clinical signs or chronic toxicity were observed through the 6 month study duration. The rAAV9-mediated rNAGLU expression was rapid and persistent in virtually all tested CNS and somatic tissues. However, acute liver toxicity occurred in 33% (5/15) WT males in the 2 × 10(14) vg/kg cohort, which was dose-dependent, sex-associated, and genotype-specific, likely due to hepatic rNAGLU overexpression. Interestingly, a significant dose response was observed only in the brain and spinal cord, whereas in the liver at 24 weeks postinfection (pi), NAGLU activity was reduced to endogenous levels in the high dose cohort but remained at supranormal levels in the low dose group. The possibility of rAAV9 germline transmission appears to be minimal. The vector delivery resulted in transient T-cell responses and characteristic acute antibody responses to both AAV9 and rNAGLU in all rAAV9-treated animals, with no detectable impacts on tissue transgene expression. This study demonstrates a generally safe and effective profile, and may have identified the upper dosing limit of rAAV9-CMV-hNAGLU via systemic delivery for the treatment of MPS IIIB.

Novel familial dilated cardiomyopathy mutation in MYL2 affects the structure and function of myosin regulatory light chain.

Dilated cardiomyopathy (DCM) is a disease of the myocardium characterized by left ventricular dilatation and diminished contractile function. Here we describe a novel DCM mutation in the myosin regulatory light chain (RLC), in which aspartic acid at position 94 is replaced by alanine (D94A). The mutation was identified by exome sequencing of three adult first-degree relatives who met formal criteria for idiopathic DCM. To obtain insight into the functional significance of this pathogenic MYL2 variant, we cloned and purified the human ventricular RLC wild-type (WT) and D94A mutant proteins, and performed in vitro experiments using RLC-mutant or WT-reconstituted porcine cardiac preparations. The mutation induced a reduction in the α-helical content of the RLC, and imposed intra-molecular rearrangements. The phosphorylation of RLC by Ca²âº/calmodulin-activated myosin light chain kinase was not affected by D94A. The mutation was seen to impair binding of RLC to the myosin heavy chain, and its incorporation into RLC-depleted porcine myosin. The actin-activated ATPase activity of mutant-reconstituted porcine cardiac myosin was significantly higher compared with ATPase of wild-type. No changes in the myofibrillar ATPase-pCa relationship were observed in wild-type- or D94A-reconstituted preparations. Measurements of contractile force showed a slightly reduced maximal tension per cross-section of muscle, with no change in the calcium sensitivity of force in D94A-reconstituted skinned porcine papillary muscle strips compared with wild-type. Our data indicate that subtle structural rearrangements in the RLC molecule, followed by its impaired interaction with the myosin heavy chain, may trigger functional abnormalities contributing to the DCM phenotype.

Feasibility and safety of systemic rAAV9-hNAGLU delivery for treating mucopolysaccharidosis IIIB: toxicology, biodistribution, and immunological assessments in primates.

No treatment is currently available for mucopolysaccharidosis (MPS) IIIB, a neuropathic lysosomal storage disease caused by autosomal recessive defect in α-N-acetylglucosaminidase (NAGLU). In anticipation of a clinical gene therapy treatment for MPS IIIB in humans, we tested the rAAV9-CMV-hNAGLU vector administration to cynomolgus monkeys (n=8) at 1E13 vg/kg or 2E13 vg/kg via intravenous injection. No adverse events or detectable toxicity occurred over a 6-month period. Gene delivery resulted in persistent global central nervous system and broad somatic transduction, with NAGLU activity detected at 2.9-12-fold above endogenous levels in somatic tissues and 1.3-3-fold above endogenous levels in the brain. Secreted rNAGLU was detected in serum. Low levels of preexisting anti-AAV9 antibodies (Abs) did not diminish vector transduction. Importantly, high-level preexisting anti-AAV9 Abs lead to reduced transduction in liver and other somatic tissues, but had no detectable impact on transgene expression in the brain. Enzyme-linked immunoabsorbent assay showed Ab responses to both AAV9 and rNAGLU in treated animals. Serum anti-hNAGLU Abs, but not anti-AAV9 Abs, correlated with the loss of circulating rNAGLU enzyme. However, serum Abs did not affect tissue rNAGLU activity levels. Weekly or monthly peripheral blood interferon-γ enzyme-linked immunospot assays detected a CD4(+) T-cell (Th-1) response to rNAGLU only at 4 weeks postinjection in one treated subject, without observable correlation to tissue transduction levels. The treatment did not result in detectable CTL responses to either AAV9 or rNAGLU. Our data demonstrate an effective and safe profile for systemic rAAV9-hNAGLU vector delivery in nonhuman primates, supporting its clinical potential in humans.

Association of common variants in ERBB4 with congenital left ventricular outflow tract obstruction defects.

BACKGROUND: The left ventricular outflow tract (LVOT) defects aortic valve stenosis (AVS), coarctation of the aorta (COA), and hypoplastic left heart syndrome (HLHS) represent an embryologically related group of congenital cardiovascular malformations. They are common and cause substantial morbidity and mortality. Prior evidence suggests a strong genetic component in their causation. METHODS: We selected NRG1, ERBB3, and ERBB4 of the epidermal growth factor receptor (EGFR) signaling pathway as candidate genes for investigation of association with LVOT defects based on the importance of this pathway in cardiac development and the phenotypes in knockout mouse models. Single nucleotide polymorphism (SNP) genotyping was performed on 343 affected case-parent trios of European ancestry. RESULTS: We identified a specific haplotype in intron 3 of ERBB4 that was positively associated with the combined LVOT defects phenotype (p=0.0005) and in each anatomic defect AVS, COA, and HLHS separately. Mutation screening of individuals with an LVOT defect failed to identify a coding sequence or splice site change in ERBB4. RT-PCR on lymphoblastoid cells from LVOT subjects did not show altered splice variant ratios among those homozygous for the associated haplotype. CONCLUSION: These results suggest ERBB4 is associated with LVOT defects. Further replication will be required in separate cohorts to confirm the consistency of the observed association.

Novel X-linked glomerulopathy is associated with a COL4A5 missense mutation in a non-collagenous interruption.

A novel COL4A5 mutation causes rapid progression to end-stage renal disease in males, despite the absence of clinical and biopsy findings associated with Alport syndrome. Affected males have proteinuria, variable hematuria, and an early progression to end-stage renal disease. Renal biopsy findings include global and segmental glomerulosclerosis, mesangial hypercellularity and basement membrane immune complex deposition. Exon sequencing of the COL4A5 locus identified a thymine to guanine transversion at nucleotide 665, resulting in a phenylalanine to cysteine missense mutation at codon 222. The phenylalanine at position 222 is absolutely conserved among vertebrates. This mutation was confirmed in 4 affected males and 4 female obligate carriers, but was absent in 6 asymptomatic male family members and 198 unrelated individuals. Immunostaining for α5(IV) collagen in renal biopsies from affected males was normal. This mutation, in a non-collagenous interruption associated with severe renal disease, provides evidence for the importance of this structural motif and suggests the range of phenotypes associated with COL4A5 mutations is more diverse than previously realized. Hence, COL4A5 mutation analysis should be considered when glomerulonephritis presents in an X-linked inheritance pattern, even with a presentation distinct from Alport syndrome.