LTBP3 Pathogenic Variants Predispose Individuals to Thoracic Aortic Aneurysms and Dissections.

The major diseases affecting the thoracic aorta are aneurysms and acute dissections, and pathogenic variants in 11 genes are confirmed to lead to heritable thoracic aortic disease. However, many families in which multiple members have thoracic aortic disease do not have alterations in the known aortopathy genes. Genes highly expressed in the aorta were assessed for rare variants in exome sequencing data from such families, and compound rare heterozygous variants (p.Pro45Argfs∗25 and p.Glu750∗) in LTBP3 were identified in affected members of one family. A homozygous variant (p.Asn678_Gly681delinsThrCys) that introduces an additional cysteine into an epidermal growth factor (EGF)-like domain in the corresponding protein, latent TGF-ß binding protein (LTBP-3), was identified in a second family. Individuals with compound heterozygous or homozygous variants in these families have aneurysms and dissections of the thoracic aorta, as well as aneurysms of the abdominal aorta and other arteries, along with dental abnormalities and short stature. Heterozygous carriers of the p.Asn678_Gly681delinsThrCys variant have later onset of thoracic aortic disease, as well as dental abnormalities. In these families, LTBP3 variants segregated with thoracic aortic disease with a combined LOD score of 3.9. Additionally, heterozygous rare LTBP3 variants were found in individuals with early onset of acute aortic dissections, and some of these variants disrupted LTBP-3 levels or EGF-like domains. When compared to wild-type mice, Ltbp3-/- mice have enlarged aortic roots and ascending aortas. In summary, homozygous LTBP3 pathogenic variants predispose individuals to thoracic aortic aneurysms and dissections, along with the previously described skeletal and dental abnormalities.

SMAD3 pathogenic variants: risk for thoracic aortic disease and associated complications from the Montalcino Aortic Consortium.

BACKGROUND: Pathogenic variants in SMAD3 cause thoracic aortic aneurysms and dissections, along with aneurysms and rupture of other arteries. Here, we examined differences in clinical presentation of aortic events (dissection or surgical repair of an aneurysm) with respect to age and variant type in an international cohort of individuals with SMAD3 variants. METHODS: Aortic status and events, vital status and clinical features were abstracted through retrospective review of medical records of 212 individuals with 51 unique SMAD3 variants, including haploinsufficiency (HI) and missense substitutions in the MH2 domain, as well as novel in-frame deletions and missense variants in the MH1 domain. RESULTS: Aortic events were documented in 37% of cases, with dissections accounting for 70% of events. The median age at first aortic event was significantly lower in individuals with SMAD3 MH2 missense variants than those with HI variants (42years vs 49 years; p=0.003), but there was no difference in frequency of aortic events by variant type. The cumulative risk of an aortic event was 50% at 54 years of age. No aortic events in childhood were observed. CONCLUSIONS: SMAD3 pathogenic variants cause thoracic aortic aneurysms and dissections in the majority of individuals with variable age of onset and reduced penetrance. Of the covariates examined, the type of underlying SMAD3 variant was responsible for some of this variation. Later onset of aortic events and the absence of aortic events in children associated with SMAD3 variants support gene-specific management of this disorder.

Assessment of the Information Sources and Interest in Research Collaboration Among Individuals with Vascular Ehlers-Danlos Syndrome.

BACKGROUND: Patient-centered research requires active engagement of patients. The vascular Ehlers-Danlos Syndrome (vEDS) research collaborative was established to ascertain patient-centered vEDS research priorities and to engage affected individuals as research partners. Evaluation of access to information and interest in research among individuals with vEDS was the first step undertaken as part of this work. METHODS: A 28-question survey was created to evaluate 4 domains of interest: diagnostic and clinical care history, vEDS experience, information resources, and willingness to collaborate with researchers. The survey was created in REDCap™ and disseminated between January and April 2018 via the vEDS social media pages, blogs, and advocacy Web sites. Results were collated and described. A single open-ended question yielded additional narrative data, which were analyzed qualitatively. RESULTS: Of the 300 responses, 228 (76%) were completed on behalf of oneself. The vEDS diagnosis was confirmed by genetic testing for 85% of respondents. When asked "Did a physician explain vEDS to you and how to manage it?" 25% answered no. Most had a primary care provider (65%), cardiologist (56%), and vascular surgeon (52%). Only 32% had a local vascular surgeon. The most commonly reported frustration was no cure/treatment available and the emergency rooms do not know what VEDS is (64.5% and 61.8%, respectively). The Internet was the most useful information source (62.3%) followed by a geneticist (18.4%). Most (87.7%) are willing to share their medical records for research studies (87.7%) and wished to be contacted about future studies (83.8%); however, only 65.4% would be willing to upload medical records via a secure confidential Web application. The most common reason for interest in research partnership was to advance research for a treatment/cure (83.8%) and helping others learn from their experiences (82.9%). The qualitative analysis provided additional insights into the patient experience living with vEDS. CONCLUSIONS: Among individuals with vEDS, there is substantial frustration with the lack of treatment, lack of knowledge among health care providers, and a high degree of interest in research involvement. The survey highlights an opportunity to discuss the optimal modality for research participation and methodologies for building trust in the research teams. The methodology lessons learned can also be applied to other rare vascular diseases.

MYLK pathogenic variants aortic disease presentation, pregnancy risk, and characterization of pathogenic missense variants.

PURPOSE: Heritable thoracic aortic disease can result from null variants in MYLK, which encodes myosin light-chain kinase (MLCK). Data on which MYLK missense variants are pathogenic and information to guide aortic disease management are limited. METHODS: Clinical data from 60 cases with MYLK pathogenic variants were analyzed (five null and two missense variants), and the effect of missense variants on kinase activity was assessed. RESULTS: Twenty-three individuals (39%) experienced an aortic event (defined as aneurysm repair or dissection); the majority of these events (87%) were aortic dissections. Aortic diameters were minimally enlarged at the time of dissection in many cases. Time-to-aortic-event curves showed that missense pathogenic variant (PV) carriers have earlier-onset aortic events than null PV carriers. An MYLK missense variant segregated with aortic disease over five generations but decreases MYLK kinase acitivity marginally. Functional Assays fail to identify all pathogenic variants in MYLK. CONCLUSION: These data further define the aortic phenotype associated with MYLK pathogenic variants. Given minimal aortic enlargement before dissection, an alternative approach to guide the timing of aortic repair is proposed based on the probability of a dissection at a given age.

Recessive mutations in VPS13D cause childhood onset movement disorders.

VPS13 protein family members VPS13A through VPS13C have been associated with various recessive movement disorders. We describe the first disease association of rare recessive VPS13D variants including frameshift, missense, and partial duplication mutations with a novel complex, hyperkinetic neurological disorder. The clinical features include developmental delay, a childhood onset movement disorder (chorea, dystonia, or tremor), and progressive spastic ataxia or paraparesis. Characteristic brain magnetic resonance imaging shows basal ganglia or diffuse white matter T2 hyperintensities as seen in Leigh syndrome and choreoacanthocytosis. Muscle biopsy in 1 case showed mitochondrial aggregates and lipidosis, suggesting mitochondrial dysfunction. These findings underline the importance of the VPS13 complex in neurological diseases and a possible role in mitochondrial function. Ann Neurol 2018;83:1089-1095.

Parent Perspectives of Support Received from Physicians and/or Genetic Counselors Following a Decision to Continue a Pregnancy with a Prenatal Diagnosis of Trisomy 13/18.

Families that choose to continue a pregnancy with a prenatal diagnosis of Trisomy 13/18 are a minority that present unique challenges for those in charge of their care. This study investigated the extent to which these patients felt supported by their healthcare providers, and any differences in the perceived level of support experienced by those working with a physician versus those working with a genetic counselor. Two online support groups, SOFT and Hope for Trisomy, distributed an online survey to their members. Means, standard deviations and chi-square analysis were calculated to describe their responses. One-hundred fourteen surveys were included in the final analysis. Respondents were more likely to agree that genetic counselors provided unbiased information in a way that they understood, compared to physicians. Review of qualitative responses found that portrayal of Trisomy 13/18 by healthcare providers used directive language when describing the lethality, morbidity and burden of the condition. Language included terms such as "incompatible with life" and comments on burden to other family members. Healthcare providers can assist families that receive a prenatal diagnosis of Trisomy 13 or 18 by providing up-to-date written resources and connecting them with support groups for parents who have received a similar diagnosis. Our study found that involving genetic counselors in the prenatal care of these patients is likely beneficial.

Recurrent HERV-H-mediated 3q13.2-q13.31 deletions cause a syndrome of hypotonia and motor, language, and cognitive delays.

We describe the molecular and clinical characterization of nine individuals with recurrent, 3.4-Mb, de novo deletions of 3q13.2-q13.31 detected by chromosomal microarray analysis. All individuals have hypotonia and language and motor delays; they variably express mild to moderate cognitive delays (8/9), abnormal behavior (7/9), and autism spectrum disorders (3/9). Common facial features include downslanting palpebral fissures with epicanthal folds, a slightly bulbous nose, and relative macrocephaly. Twenty-eight genes map to the deleted region, including four strong candidate genes, DRD3, ZBTB20, GAP43, and BOC, with important roles in neural and/or muscular development. Analysis of the breakpoint regions based on array data revealed directly oriented human endogenous retrovirus (HERV-H) elements of ~5 kb in size and of >95% DNA sequence identity flanking the deletion. Subsequent DNA sequencing revealed different deletion breakpoints and suggested nonallelic homologous recombination (NAHR) between HERV-H elements as a mechanism of deletion formation, analogous to HERV-I-flanked and NAHR-mediated AZFa deletions. We propose that similar HERV elements may also mediate other recurrent deletion and duplication events on a genome-wide scale. Observation of rare recurrent chromosomal events such as these deletions helps to further the understanding of mechanisms behind naturally occurring variation in the human genome and its contribution to genetic disease.

Molecular genetic testing for hereditary ataxia: What every neurologist should know.

PURPOSE OF REVIEW: Because of extensive clinical overlap among many forms of hereditary ataxia, molecular genetic testing is often required to establish a diagnosis. Interrogation of multiple genes has become a popular diagnostic approach as the cost of sequence analysis has decreased and the number of genes associated with overlapping phenotypes has increased. We describe the benefits and limitations of molecular genetic tests commonly used to determine the etiology of hereditary ataxia. RECENT FINDINGS: There are more than 300 hereditary disorders associated with ataxia. The most common causes of hereditary ataxia are expansion of nucleotide repeats within 7 genes: ATXN1, ATXN2, ATXN3, ATXN7, ATXN8, CACNA1A (spinocerebellar ataxia type 6), and FXN (Friedreich ataxia). Recent reports describing the use of clinical exome sequencing to identify causes of hereditary ataxia may lead neurologists to start their clinical investigation with a less sensitive molecular test providing a misleading "negative" result. SUMMARY: The majority of individuals with hereditary ataxias have nucleotide repeat expansions, pathogenic variants that are not detectable with clinical exome sequencing. Multigene panels that include specific assays to determine nucleotide repeat lengths should be considered first in individuals with hereditary ataxia.

Impact of preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria on the incidence of sepsis following transrectal ultrasound guided prostate biopsy.

With the universal adoption of antibiotic prophylaxis prior to prostate biopsy, the current risk of post-biopsy infection (including sepsis) is <2%. Preoperative prophylactic antibiotic regimens can vary, and although fluoroquinolones have emerged as the standard of care, there is no universally agreed upon preoperative antibiotic regimen. Recently, an increase in the proportion of postoperative infections caused by fluoroquinolone-resistant Escherichia coli (as well as other Enterobacteriaceae) has led to the exploration of simple, practical, and cost-effective methods to minimize this postoperative infection risk. We performed a prospective, nonrandomized, controlled study of preoperative rectal cultures to screen for rectal colonization with fluoroquinolone-resistant bacteria using ciprofloxacin-supplemented MacConkey agar culture media. To evaluate the feasibility and practicality of this test, one provider used the results of rectal swab cultures collected during the preoperative outpatient evaluation to adjust each patient's preoperative antibiotic prophylaxis when fluoroquinolone-resistant enteric bacteria were detected, whereas two other providers continued usual preoperative care and empiric antimicrobial prophylaxis. Rectal colonization with fluoroquinolone-resistant bacteria was detected in 19/152 (12.5%) of patients. In our intention-to-treat analysis (N=268), the rate of post-biopsy sepsis was 3.6% lower in the group that was screened for rectal colonization with fluoroquinolone-resistant bacteria prior to transrectal prostate biopsy. The observed risk reduction in the rectal screening group trended toward, but did not achieve, statistical significance. We suggest that preoperative screening for rectal colonization with fluoroquinolone-resistant enteric bacteria may be a useful step toward mitigating post-prostate biopsy sepsis.

Improving the value of costly genetic reference laboratory testing with active utilization management.

CONTEXT: Tests that are performed outside of the ordering institution, send-out tests, represent an area of risk to patients because of complexity associated with sending tests out. Risks related to send-out tests include increased number of handoffs, ordering the wrong or unnecessary test, specimen delays, data entry errors, preventable delays in reporting and acknowledging results, and excess financial liability. Many of the most expensive and most misunderstood tests are send-out genetic tests. OBJECTIVE: To design and develop an active utilization management program to reduce the risk to patients and improve value of genetic send-out tests. DESIGN: Send-out test requests that met defined criteria were reviewed by a rotating team of doctoral-level consultants and a genetic counselor in a pediatric tertiary care center. RESULTS: Two hundred fifty-one cases were reviewed during an 8-month period. After review, nearly one-quarter of genetic test requests were modified in the downward direction, saving a total of 2% of the entire send-out bill and 19% of the test requests under management. Ultimately, these savings were passed on to patients. CONCLUSIONS: Implementing an active utilization strategy for expensive send-out tests can be achieved with minimal technical resources and results in improved value of testing to patients.

A novel missense mutation in POMT1 modulates the severe congenital muscular dystrophy phenotype associated with POMT1 nonsense mutations.

Mutations in POMT1 lead to a group of neuromuscular conditions ranging in severity from Walker-Warburg syndrome to limb girdle muscular dystrophy. We report two male siblings, ages 19 and 14, and an unrelated 6-year old female with early onset muscular dystrophy and intellectual disability with minimal structural brain anomalies and no ocular abnormalities. Compound heterozygous mutations in POMT1 were identified including a previously reported nonsense mutation (c.2167dupG; p.Asp723Glyfs*8) associated with Walker-Warburg syndrome and a novel missense mutation in a highly conserved region of the protein O-mannosyltransferase 1 protein (c.1958C>T; p.Pro653Leu). This novel variant reduces the phenotypic severity compared to patients with homozygous c.2167dupG mutations or compound heterozygous patients with a c.2167dupG mutation and a wide range of other mutant POMT1 alleles.

Marked phenotypic variability in progressive diaphyseal dysplasia (Camurati-Engelmann disease): report of a four-generation pedigree, identification of a mutation in TGFB1, and review.

Progressive diaphyseal dysplasia (PDD) (Camurati-Engelmann disease) is an autosomal dominant craniotubular dysplasia characterized by hyperostosis and sclerosis of the diaphyses of the long bones and the skull. Mutations in transforming growth factor beta-1 (TGFB1) were recently found in patients with PDD. We report on a four-generation pedigree with seven individuals affected by PDD, linkage and mutational analysis results, and review the literature. This pedigree demonstrates the autosomal dominant inheritance pattern, remarkable variation in expressivity, and reduced penetrance. The most severely affected individual had progression of mild skull hyperostosis to severe skull thickening and cranial nerve compression over 30 years. His carrier father remained asymptomatic into his ninth decade and had no radiographic hyperostosis or sclerosis of the bones. Symptomatic relatives presented with lower limb pain and weakness. They were initially diagnosed with a variety of other conditions. Two of the symptomatic individuals were treated successfully with prednisone. We genotyped 7 markers from chromosome region 19q13.1-13.3 in 15 relatives and confirmed linkage to this region in this family. We screened the TGFB1 gene for mutations and identified a missense mutation resulting in an R218H substitution in the affected individuals, the asymptomatic obligate carrier, and another unaffected relative. We genotyped the family for seven known TGFB1 polymorphisms and a novel TAAA tetranucleotide repeat in intron 1. These polymorphisms did not appear to account for the variability in disease severity in this family. Our review illustrates how the disorder can significantly compromise health. Cranial involvement, which occurs in 61% of patients, can be severe, entrapping cranial nerves or causing increased intracranial pressure. Therapy with corticosteroids should be attempted in all symptomatic patients.