Genetic diagnosis and detection rates using C9orf72 repeat expansion and a multi-gene panel in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder. It is mostly sporadic, with the C9orf72 repeat expansion being the most common genetic cause. While the prevalence of C9orf72-ALS in patients from different populations has been studied, data regarding the yield of C9orf72 compared to an ALS gene panel testing is limited.We aimed to explore the application of C9orf72 versus a gene panel in the general Israeli population. A total of 140 ALS patients attended our Neurogenetics Clinic throughout 2018-2023. Disease onset was between ages 60 and 69 years for most patients (34%); however, a quarter had an early-onset disease (< 50 years). Overall, 119 patients (85%) were genetically evaluated: 116 (97%) were tested for the C9orf72 repeat expansion and 64 (54%) underwent gene panel testing. The C9orf72 repeat expansion had a prevalence of 21% among Ashkenazi Jewish patients compared to 5.7% in non-Ashkenazi patients, while the gene panel had a higher yield in non-Ashkenazi patients with 14% disease-causing variants compared to 5.7% in Ashkenazi Jews. Among early-onset ALS patients, panel testing was positive in 12% compared to 2.9% for C9orf72.We suggest a testing strategy for the Israeli ALS patients: C9orf72 should be the first-tier test in Ashkenazi Jewish patients, while a gene panel should be considered as the first step in non-Ashkenazi and early-onset patients. Tiered testing has important implications for patient management, including prognosis, ongoing clinical trials, and prevention in future generations. Similar studies should be implemented worldwide to uncover the diverse ALS genetic architecture and facilitate tailored care.

Telemedicine Versus Traditional In-Person Consultations: Comparison of Patient Satisfaction Rates

Introduction: Data on patient satisfaction with the provision of genetic consultations using telemedicine are limited, especially those involving children. We compared patient satisfaction rates with telemedicine services versus traditional in-person encounters. Methods: A cross-sectional questionnaire-based study was conducted between January and June 2020. Questionnaires were distributed online to 1,672 consecutive patients who had received genetic counseling at our Genetics Institute in the clinical fields of adult and pediatric genetics, oncogenetics, and prenatal genetics, through in-person and/or telemedicine consultation. We used Likert scale with scores of 4-5 representing "satisfied"-"very satisfied" and 1-2 representing "very unsatisfied"-"unsatisfied." Results: The response rate was 27.3% (400 adults and 57 children <18 years), including 330 who had received in-person consultations (72.2%), 80 telemedicine consultations (17.5%), and 47 both consultations (10.3%). Mean satisfactory scores of 4-5 were reported by 82.1% in the in-person group versus 82.5% in the telemedicine group (p = 0.88). Mean scores of 1-2 were reported by 6.3% in the in-person group versus 11.2% in the telemedicine group (p = 0.31). No pediatric telemedicine group patient (n 12 = ) gave scores of 1-2 compared with 2/33 (6%) patients who had in-person pediatric consultations (p = 0.62). Most responders who had been counseled through telemedicine (n = 127, 84%) indicated willingness to use genetic services through telemedicine again. Conclusions: Users of genetic counseling through telemedicine, especially in the pediatric age group, were very satisfied at rates comparable to those of in-person consultations. Future research should evaluate patient compliance and views according to session type, information provided (e.g., diagnostic vs. negative results), and its nature (good vs. bad news).

National Rapid Genome Sequencing in Neonatal Intensive Care

Importance

National implementation of rapid trio genome sequencing (rtGS) in a clinical acute setting is essential to ensure advanced and equitable care for ill neonates.

Objective

To evaluate the feasibility, diagnostic efficacy, and clinical utility of rtGS in neonatal intensive care units (NICUs) throughout Israel.

Design, Setting, and Participants

This prospective, public health care-based, multicenter cohort study was conducted from October 2021 to December 2022 with the Community Genetics Department of the Israeli Ministry of Health and all Israeli medical genetics institutes (n = 18) and NICUs (n = 25). Critically ill neonates suspected of having a genetic etiology were offered rtGS. All sequencing, analysis, and interpretation of data were performed in a central genomics center at Tel-Aviv Sourasky Medical Center. Rapid results were expected within 10 days. A secondary analysis report, issued within 60 days, focused mainly on cases with negative rapid results and actionable secondary findings. Pathogenic, likely pathogenic, and highly suspected variants of unknown significance (VUS) were reported.

Main Outcomes and Measures

Diagnostic rate, including highly suspected disease-causing VUS, and turnaround time for rapid results. Clinical utility was assessed via questionnaires circulated to treating neonatologists.

Results

A total of 130 neonates across Israel (70 [54%] male; 60 [46%] female) met inclusion criteria and were recruited. Mean (SD) age at enrollment was 12 (13) days. Mean (SD) turnaround time for rapid report was 7 (3) days. Diagnostic efficacy was 50% (65 of 130) for disease-causing variants, 11% (14 of 130) for VUS suspected to be causative, and 1 novel gene candidate (1%). Disease-causing variants included 12 chromosomal and 52 monogenic disorders as well as 1 neonate with uniparental disomy. Overall, the response rate for clinical utility questionnaires was 82% (107 of 130). Among respondents, genomic testing led to a change in medical management for 24 neonates (22%). Results led to immediate precision medicine for 6 of 65 diagnosed infants (9%), an additional 2 (3%) received palliative care, and 2 (3%) were transferred to nursing homes.

Conclusions and Relevance

In this national cohort study, rtGS in critically ill neonates was feasible and diagnostically beneficial in a public health care setting. This study is a prerequisite for implementation of rtGS for ill neonates into routine care and may aid in design of similar studies in other public health care systems.

Biallelic MED27 variants lead to variable ponto-cerebello-lental degeneration with movement disorders

MED27 is a subunit of the Mediator multiprotein complex, which is involved in transcriptional regulation. Biallelic MED27 variants have recently been suggested to be responsible for an autosomal recessive neurodevelopmental disorder with spasticity, cataracts and cerebellar hypoplasia. We further delineate the clinical phenotype of MED27-related disease by characterizing the clinical and radiological features of 57 affected individuals from 30 unrelated families with biallelic MED27 variants. Using exome sequencing and extensive international genetic data sharing, 39 unpublished affected individuals from 18 independent families with biallelic missense variants in MED27 have been identified (29 females, mean age at last follow-up 17 ± 12.4 years, range 0.1-45). Follow-up and hitherto unreported clinical features were obtained from the published 12 families. Brain MRI scans from 34 cases were reviewed. MED27-related disease manifests as a broad phenotypic continuum ranging from developmental and epileptic-dyskinetic encephalopathy to variable neurodevelopmental disorder with movement abnormalities. It is characterized by mild to profound global developmental delay/intellectual disability (100%), bilateral cataracts (89%), infantile hypotonia (74%), microcephaly (62%), gait ataxia (63%), dystonia (61%), variably combined with epilepsy (50%), limb spasticity (51%), facial dysmorphism (38%) and death before reaching adulthood (16%). Brain MRI revealed cerebellar atrophy (100%), white matter volume loss (76.4%), pontine hypoplasia (47.2%) and basal ganglia atrophy with signal alterations (44.4%). Previously unreported 39 affected individuals had seven homozygous pathogenic missense MED27 variants, five of which were recurrent. An emerging genotype-phenotype correlation was observed. This study provides a comprehensive clinical-radiological description of MED27-related disease, establishes genotype-phenotype and clinical-radiological correlations and suggests a differential diagnosis with syndromes of cerebello-lental neurodegeneration and other subtypes of 'neuro-MEDopathies'.

Utility of genetic testing in children with leukodystrophy

BACKGROUND

Leukodystrophies are monogenic disorders primarily affecting the white matter. We aimed to evaluate the utility of genetic testing and time-to-diagnosis in a retrospective cohort of children with suspected leukodystrophy.

METHODS

Medical records of patients who attended the leukodystrophy clinic at the Dana-Dwek Children's Hospital between June 2019 and December 2021 were retrieved. Clinical, molecular, and neuroimaging data were reviewed, and the diagnostic yield was compared across genetic tests.

RESULTS

Sixty-seven patients (Female/Male ratio 35/32) were included. Median age at symptom onset was 9 months (interquartile range (IQR) 3-18 months), and median length of follow-up was 4.75 years (IQR 3-8.5). Time from symptom onset to a confirmed genetic diagnosis was 15months (IQR 11-30). Pathogenic variants were identified in 60/67 (89.6%) patients; classic leukodystrophy (55/67, 82.1%), leukodystrophy mimics (5/67, 7.5%). Seven patients (10.4%) remained undiagnosed. Exome sequencing showed the highest diagnostic yield (34/41, 82.9%), followed by single-gene sequencing (13/24, 54%), targeted panels (3/9, 33.3%) and chromosomal microarray (2/25, 8%). Familial pathogenic variant testing confirmed the diagnosis in 7/7 patients. A comparison between patients who presented before (n = 31) and after (n = 21) next-generation sequencing (NGS) became clinically available in Israel revealed that the time-to-diagnosis was shorter in the latter group with a median of 12months (IQR 3.5-18.5) vs. a median of 19 months (IQR 13-51) (p = 0.005).

CONCLUSIONS

NGS carries the highest diagnostic yield in children with suspected leukodystrophy. Access to advanced sequencing technologies accelerates speed to diagnosis, which is increasingly crucial as targeted treatments become available.

Exome sequencing as first-tier test for fetuses with severe central nervous system structural anomalies

OBJECTIVE

Prenatally detected central nervous system (CNS) anomalies present a diagnostic challenge. In this study, we compared the diagnostic yield of exome sequencing (ES) and chromosomal microarray analysis (CMA) in fetuses with a major CNS anomaly.

METHODS

This was a retrospective study of 114 cases referred for genetic evaluation following termination of pregnancy (TOP) due to a major CNS anomaly detected on prenatal ultrasound. All fetuses were first analyzed by CMA. All CMA-negative cases were offered ES. CMA-positive cases were reanalyzed using ES to assess its ability to detect copy-number variants (CNVs).

RESULTS

CMA identified a pathogenic or likely pathogenic (P/LP) CNV in 11/114 (10%) cases. Eighty-six CMA-negative cases were analyzed using ES, which detected P/LP sequence variants in 38/86 (44%). Among recurrent cases (i.e. cases with a previously affected pregnancy), the incidence of P/LP sequence variants was non-significantly higher compared with non-recurrent ones (12/19 (63%) vs 26/67 (39%); P = 0.06). Among the 38 cases with an ES diagnosis, 20 (53%) were inherited and carried a significant risk of recurrence. Reanalysis of 10 CMA-positive cases by ES demonstrated that the bioinformatics pipeline used for sequence variant analysis also detected all P/LP CNVs, as well as three previously known non-causative CNVs.

CONCLUSIONS

In our study, ES provided a high diagnostic yield (> 50%) in fetuses with severe CNS structural anomalies, which may have been partly due to the highly selected case series that included post-TOP cases from a specialist referral center. These data suggest that ES may be considered as a first-tier test for the prenatal diagnosis of major fetal CNS anomalies, detecting both P/LP sequence variants and CNVs. This is of particular importance given the time constraints of an ongoing pregnancy and the risk of recurrence in future pregnancies. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Biallelic loss of EMC10 leads to mild to severe intellectual disability

The endoplasmic reticulum membrane protein complex subunit 10 (EMC10) is a highly conserved protein responsible for the post‐translational insertion of tail‐anchored membrane proteins into the endoplasmic reticulum in a defined topology. Two biallelic variants in EMC10 have previously been associated with a neurodevelopmental disorder. Utilizing exome sequencing and international data sharing we have identified 10 affected individuals from six independent families with five new biallelic loss‐of‐function and one previously reported recurrent EMC10 variants. This report expands the molecular and clinical spectrum of EMC10 deficiency, provides a comprehensive dysmorphological assessment and highlights an overlap between the clinical features of EMC10‐and EMC1‐related disease.

De novo variants in ATP2B1 lead to neurodevelopmental delay

Calcium (Ca²⁺) is a universal second messenger involved in synaptogenesis and cell survival; consequently, its regulation is important for neurons. ATPase plasma membrane Ca²⁺ transporting 1 (ATP2B1) belongs to the family of ATP-driven calmodulin-dependent Ca²⁺ pumps that participate in the regulation of intracellular free Ca²⁺. Here, we clinically describe a cohort of 12 unrelated individuals with variants in ATP2B1 and an overlapping phenotype of mild to moderate global development delay. Additional common symptoms include autism, seizures, and distal limb abnormalities. Nine probands harbor missense variants, seven of which were in specific functional domains, and three individuals have nonsense variants. 3D structural protein modeling suggested that the variants have a destabilizing effect on the protein. We performed Ca²⁺ imaging after introducing all nine missense variants in transfected HEK293 cells and showed that all variants lead to a significant decrease in Ca²⁺ export capacity compared with the wild-type construct, thus proving their pathogenicity. Furthermore, we observed for the same variant set an incorrect intracellular localization of ATP2B1. The genetic findings and the overlapping phenotype of the probands as well as the functional analyses imply that de novo variants in ATP2B1 lead to a monogenic form of neurodevelopmental disorder.

Concomitant variants in NF1, LZTR1 and GNAZ genes probably contribute to the aggressiveness of plexiform neurofibroma and warrant treatment with MEK inhibitor

Neurofibromatosis 1 (NF1) is caused by germline mutations in the NF1 gene and manifests as proliferation of various tissues, including plexiform neurofibromas. The plexiform neurofibroma phenotype varies from indolent to locally aggressive, suggesting contributions of other modifiers in addition to somatic loss of NF1. In this study, we investigated a life-threatening plexiform neurofibroma in a 9-month-old female infant with NF1. Germline mutations in two RASopathy-associated genes were identified using whole-exome sequencing-a de novo pathogenic variant in the NF1 gene, and a known pathogenic variant in the LZTR1 gene. Somatic analysis of the plexiform neurofibroma revealed NF1 loss of heterozygosity and a variant in GNAZ, a gene encoding a G protein-coupled receptor. Cells expressing mutant GNAZ exhibited increased ERK 1/2 activation compared to those expressing wild-type GNAZ. Taken together, we suggest the variants in NF1, LZRT1 and GNAZ act synergistically in our patient, leading to MAPK pathway activation and contributing to the severity of the patient's plexiform neurofibromatosis. After treatment with the MEK inhibitor, trametinib, a prominent clinical improvement was observed in this patient. This case study contributes to the knowledge of germline and somatic non-NF1 variants affecting the NF1 clinical phenotype and supports use of personalized, targeted therapy.

The phenotype of 15 cases with rare 8q24.13-q24.3 deletions-A new syndrome or still an enigma?

Diagnosis of rare copy number variants (CNVs) with scarce literature evidence poses a major challenge for interpretation of the clinical significance of chromosomal microarray analysis (CMA) results, especially in the prenatal setting. Bioinformatic tools can be used to assist in this issue; however, this prediction can be imprecise. Our objective was to describe the phenotype of the rare copy number losses encompassing the 8q24.13-q24.3 locus, and to find common features in terms of genomic coordinates, gene content, and clinical phenotypic characteristics. Appropriate cases were retrieved using local databases of two largest Israeli centers performing CMA analysis. In addition, literature and public databases search was performed. Local database search yielded seven new patients with del (8)(q24.13q24.3) (one of these with an additional copy number variant). Literature and public databases search yielded eight additional patients. The cases showed high phenotypic variability, ranging from asymptomatic adults and fetuses with normal ultrasound to patients with autism/developmental delay (6/11 postnatal cases, 54.5%). No clear association was noted between the specific disease-causing/high-pLI gene content of the described del (8)(q24.13q24.3) to neurodevelopmental disorders, except for a possibly relevant locus encompassing the KCNQ3 gene. We present the challenges in classification of rare variants with limited clinical information. In such cases, genotype-phenotype correlation must be assessed with extra-caution and possibly using additional methods to assist the classification, especially in the prenatal setting.

Genetics of tuberous sclerosis complex: an update

PURPOSE

To review the current genetic aspects of tuberous sclerosis complex.

METHODS

Review of the literature.

RESULTS

Tuberous sclerosis complex (TSC), a long known childhood-onset monogenic disorder, characterized by hamartoma formation affecting mainly the brain, heart, kidney, lung, and skin, is associated with a high morbidity burden and risk of a reduced life span. The identification of TSC1 and TSC2, as tumor suppressor genes causative of the disorder, led to the elucidation of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway and its pivotal role in the pathogenesis of hamartoma formation. This knowledge was translated into standard clinical practice with the discovery of rapamycin, and additional analogues, as inhibitors of mTORC1.

CONCLUSION

Next-generation sequencing was proven to be fundamental to drive research of tumorigenesis in TSC, hopefully leading to new therapeutic options in the future.

Detection of copy number variations in epilepsy using exome data

Epilepsies are common neurological disorders and genetic factors contribute to their pathogenesis. Copy number variations (CNVs) are increasingly recognized as an important etiology of many human diseases including epilepsy. Whole-exome sequencing (WES) is becoming a standard tool for detecting pathogenic mutations and has recently been applied to detecting CNVs. Here, we analyzed 294 families with epilepsy using WES, and focused on 168 families with no causative single nucleotide variants in known epilepsy-associated genes to further validate CNVs using 2 different CNV detection tools using WES data. We confirmed 18 pathogenic CNVs, and 2 deletions and 2 duplications at chr15q11.2 of clinically unknown significance. Of note, we were able to identify small CNVs less than 10 kb in size, which might be difficult to detect by conventional microarray. We revealed 2 cases with pathogenic CNVs that one of the 2 CNV detection tools failed to find, suggesting that using different CNV tools is recommended to increase diagnostic yield. Considering a relatively high discovery rate of CNVs (18 out of 168 families, 10.7%) and successful detection of CNV with <10 kb in size, CNV detection by WES may be able to surrogate, or at least complement, conventional microarray analysis.

[TRMU MUTATIONS - REVERSIBLE INFANTILE LIVER FAILURE OR MULTISYSTEM DISORDER?]

INTRODUCTION

Bi-allelic mutations in the TRMU gene cause reversible infantile liver failure. Little is known about extra-hepatic manifestations in these patients.

BACKGROUND

Two infants, aged 4 and 5 months, presented with progressive life threatening liver failure, characterized by lactic acidosis, highly elevated alpha-fetoprotein and recurrent hypoglycemia. Both showed significant extra-hepatic findings, including: hypothyroidism, macrocytic anemia and microcephaly. Both were of Jewish Yemenite descent and homozygous for Y77H mutation in the TRMU gene.

CONCLUSIONS

TRMU bi-allelic mutations cause severe life-threatening liver failure. Extra-hepatic involvement is common and should be evaluated. Spontaneous resolution and recovery occurs in most patients with a remarkably good long-term prognosis. Liver failure in a Jewish-Yemenite infant should prompt early genetic testing for TRMU Y77H mutation. Pediatricians should be aware of this disease and the common mutation in Israel.

DISCUSSION

Nineteen additional patients were described in the literature, of whom 13 were from Israel; 6/19 (31%) manifested extra-hepatic involvement, namely: myopathic weakness, cardiomyopathy, renomegaly and proteinuria, bulbar dysfunction, cerebral white matter changes and abnormal growth including microcephaly. Mortality was 24% (5/21). Survivors (16/21, 76%) showed complete recovery and resolution of clinical, laboratory and histologic abnormalities. Most Israeli patients (10/15) were of Jewish-Yemenite ancestry. Homozygous Y77H genotype was exclusive to this patient subgroup and was associated with a 100% survival and recovery rate.

Homozygous deletion of RAG1, RAG2 and 5' region TRAF6 causes severe immune suppression and atypical osteopetrosis

Mutations of several genes have been implicated in autosomal recessive osteopetrosis (OP), a disease caused by impaired function and differentiation of osteoclasts. Severe combined immune deficiencies (SCID) can likewise result from different genetic mutations. We report two siblings with SCID and an atypical phenotype of OP. A biallelic microdeletion encompassing the 5' region of TRAF6, RAG1 and RAG2 genes was identified. TRAF6, a tumor necrosis factor receptor-associated family member, plays an important role in T cell signaling and in RANKL-dependent osteoclast differentiation and activation but its role in human OP has not been previously reported. The RAG proteins are essential for recombination of B and T cell receptors, and for the survival and differentiation of these cells. This is the first study to report a homozygous deletion of TRAF6 as a cause of human disease.

[INFECTIONS AND THE IMMUNE SYSTEM - TOWARDS PERSONALIZED MEDICINE]

The main role of the human immune system is to protect against infectious agents. The concept of immune deficiencies as rare conditions associated with multiple severe infections has changed to relatively common genetic variations, leading to minor changes mainly in the innate immunity and specific host-pathogen interactions. For example, molecular studies have identified polymorphisms associated with increased susceptibility to severe tuberculosis in children, herpes encephalitis, renal scar formation after urinary tract infections and adverse events after vaccination, and on the other hand, genetic-based resistance to the human immunodeficiency virus. It seems that we are approaching safer and more efficacious personalized medicine.

Nonbullous Erythema Multiforme in Hospitalized Children: A 10-Year Survey

BACKGROUND

Nonbullous erythema multiforme (NBEM) is an acute, immune-mediated, self-limiting skin disease with distinctive target lesions. Its pathogenesis is unclear, but most cases are considered to be infection related or drug related. In adults, the main precipitating factor is infection. This study reviewed a 10-year experience with hospitalized children with NBEM in a tertiary pediatric medical center in Israel with a focus on precipitating factors.

METHODS

The medical files of all children hospitalized from 2001 to 2011 with the diagnosis of NBEM were reviewed.

RESULTS

Ninety-seven patients (55 boys and 42 girls) met the inclusion criteria. The mean age was 4.0 years. At least one precipitating factor was recognized in 72 cases; the remainders were classified as idiopathic. The most common factor was drugs (n = 45), particularly penicillin (n = 30), followed by infection with various pathogens (n = 27) including Epstein-Barr virus (7), group A Streptococcus (n = 6), Mycoplasma pneumoniae (n = 5) and herpes simplex virus (n = 4). Analysis according to age showed that medication was the most common precipitating factor in the first year of life, and infection was as common as drugs in the older age groups (1-18 years).

CONCLUSIONS

Unlike adult NBEM, the majority of pediatric NBEM is associated with medications, especially penicillin. This may be due to the frequent use of antibiotics in children.

A possible genotype-phenotype correlation in Ashkenazi-Jewish individuals with Aicardi-Goutières syndrome associated with SAMHD1 mutation

Aicardi-Goutières syndrome is a genetic neurodegenerative disorder with clinical symptoms mimicking a congenital viral infection. Mutations in 6 genes are known to cause the disease: 3 prime repair exonuclease1, ribonucleases H2A, B, and C, SAM domain and HD domain 1, and most recently ADAR1. HD domain 1 mutations were previously reported in the Ashkenazi-Jewish community. We report an additional patient of Ashkenazi-Jewish descent and review the other 3 cases affected with Aicardi-Goutières syndrome due to SAM domain and HD domain 1 (SAMHD1) mutations described in Israel. We propose that there may be a phenotypic-genotypic correlation in accordance with the type of mutations inherited in the SAMHD1 genotype and suggest that Aicardi-Goutières syndrome may not be a rare disease in the Ashkenazi-Jewish population.

Infective endocarditis in previously healthy children with structurally normal hearts

Structural heart disease, intravascular catheters, and invasive procedures are predisposing factors for infective endocarditis (IE). Data on IE in children with structurally normal hearts and no predisposing factors are limited. We aim to characterize IE (definite or possible by Duke criteria) in such a subgroup of pediatric patients (age <18 years) who were treated at our medical center. Of 51 events of IE in 50 children, 9 (18 %) had no predisposing factors. These infections were all community-acquired and presented with fever, a newly detected heart murmur, diagnostic echocardiographic findings, and left-sided infection. Clinical course was characterized by acute onset (n = 8 of 9) with a 100 % complication rate (heart failure or embolic phenomena). Emergency cardiac surgery was performed in 7 children (Ross surgery [n = 4], mitral valve replacement [MVR; n = 2], and valve repair [n = 1]). Causative organisms were S. aureus (n = 3), S. pneumoniae (n = 2), H. parainfluenzae (n = 1), and K. kingae (n = 1). In contrast, IE in children with predisposing factors (42 of 51 [82 %]) was frequently health care-associated (30 of 42), right-sided (20 of 42, p = 0.041), and with lower rates of diagnostic echocardiographic findings (28 of 42, p = 0.041), complications (16 of 42, p < 0.001), and surgical intervention (9 of 42, p = 0.002). Causative organisms were mainly viridans streptococci (n = 9), Candida species (n = 8), coagulase-negative staphylococci (n = 6), enteric Gram-negative bacilli (n = 6), S. aureus (n = 5), and K. kingae (n = 3). Mortality was 11 % in both groups. We conclude that pediatric IE in children with and without predisposing factors differs significantly. Due to the acute and complicated course of the latter, high awareness among pediatricians and prompt diagnosis are crucial.

[Trends in pediatric infective endocarditis in a tertiary pediatric center in Israel]

INTRODUCTION

The characteristics of pediatric infective endocarditis (IE) are continuously changing.

OBJECTIVES

To describe trends in pediatric IE over a period of 25 years.

STUDY METHODS

Children (< 18 years old] treated at Schneider Children's Medical Center during 1992-2004 who met Duke criteria for definite or possible IE were included in the study. Demographic, clinical and laboratory data were collected and compared to data gathered during 1980-1991.

RESULTS

Compared to 1980-1991, during 1992-2004 we noted a decrease in the mean age from 6.5 to 4 years and in the incidence of congenital heart defects from 96% to 61% (p = 0.001). Incidence of significant underlying diseases and non-cardiac predisposing factors rose from 4% to 43%. Significantly Less children presented with fever, splenomegaly and murmur during 1992-2004; a 4-fold increase in surgical intervention [p = 0.024) and a 3-fold increase in mortality p = 0.257 were observed. Viridans streptococci (37.5%), Staphylococcus aureus (20.8%) and gram-negative bacilli 2.5%] caused most of IE during 1980-1992, whereas viridians streptococci (19.1%), Candida spp (17%), S. aureus (17%) and coagulase-negative staphylococci (12.8%) were the common causes during 1992-2004.

CONCLUSIONS

Considerable changes in pediatric IE were observed.

DISCUSSION AND SUMMARY

Pediatric IE became an infection of young children, especially those with significant noncardiac underlying diseases. It is less commonly caused by viridans streptococci and is increasingly caused by Candida spp and coagulase-negative staphylococci. These trends may affect the management of pediatric IE.

Acute infantile liver failure due to mutations in the TRMU gene

Acute liver failure in infancy accompanied by lactic acidemia was previously shown to result from mtDNA depletion. We report on 13 unrelated infants who presented with acute liver failure and lactic acidemia with normal mtDNA content. Four died during the acute episodes, and the survivors never had a recurrence. The longest follow-up period was 14 years. Using homozygosity mapping, we identified mutations in the TRMU gene, which encodes a mitochondria-specific tRNA-modifying enzyme, tRNA 5-methylaminomethyl-2-thiouridylate methyltransferase. Accordingly, the 2-thiouridylation levels of the mitochondrial tRNAs were markedly reduced. Given that sulfur is a TRMU substrate and its availability is limited during the neonatal period, we propose that there is a window of time whereby patients with TRMU mutations are at increased risk of developing liver failure.

Mutations involved in Aicardi-Goutières syndrome implicate SAMHD1 as regulator of the innate immune response

Aicardi-Goutières syndrome is a mendelian mimic of congenital infection and also shows overlap with systemic lupus erythematosus at both a clinical and biochemical level. The recent identification of mutations in TREX1 and genes encoding the RNASEH2 complex and studies of the function of TREX1 in DNA metabolism have defined a previously unknown mechanism for the initiation of autoimmunity by interferon-stimulatory nucleic acid. Here we describe mutations in SAMHD1 as the cause of AGS at the AGS5 locus and present data to show that SAMHD1 may act as a negative regulator of the cell-intrinsic antiviral response.

Clinical and molecular phenotype of Aicardi-Goutieres syndrome

Aicardi-Goutieres syndrome (AGS) is a genetic encephalopathy whose clinical features mimic those of acquired in utero viral infection. AGS exhibits locus heterogeneity, with mutations identified in genes encoding the 3'-->5' exonuclease TREX1 and the three subunits of the RNASEH2 endonuclease complex. To define the molecular spectrum of AGS, we performed mutation screening in patients, from 127 pedigrees, with a clinical diagnosis of the disease. Biallelic mutations in TREX1, RNASEH2A, RNASEH2B, and RNASEH2C were observed in 31, 3, 47, and 18 families, respectively. In five families, we identified an RNASEH2A or RNASEH2B mutation on one allele only. In one child, the disease occurred because of a de novo heterozygous TREX1 mutation. In 22 families, no mutations were found. Null mutations were common in TREX1, although a specific missense mutation was observed frequently in patients from northern Europe. Almost all mutations in RNASEH2A, RNASEH2B, and RNASEH2C were missense. We identified an RNASEH2C founder mutation in 13 Pakistani families. We also collected clinical data from 123 mutation-positive patients. Two clinical presentations could be delineated: an early-onset neonatal form, highly reminiscent of congenital infection seen particularly with TREX1 mutations, and a later-onset presentation, sometimes occurring after several months of normal development and occasionally associated with remarkably preserved neurological function, most frequently due to RNASEH2B mutations. Mortality was correlated with genotype; 34.3% of patients with TREX1, RNASEH2A, and RNASEH2C mutations versus 8.0% RNASEH2B mutation-positive patients were known to have died (P=.001). Our analysis defines the phenotypic spectrum of AGS and suggests a coherent mutation-screening strategy in this heterogeneous disorder. Additionally, our data indicate that at least one further AGS-causing gene remains to be identified.

Low estriol levels in the maternal triple-marker screen as a predictor of isolated adrenocorticotropic hormone deficiency caused by a new mutation in the TPIT gene

Isolated adrenocorticotropic hormone (ACTH) deficiency (IAD) is a rare cause of adrenocortical insufficiency, especially in children, and may be an underestimated cause of neonatal death. Early postnatal diagnosis may prevent hypoglycemic seizures, Addisonian crises, and death. There are also occasional reports of prenatal diagnosis of IAD by findings on the maternal triple-marker screen (TMST), a combined serum analyte test that measures levels of alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol for the detection of Down syndrome and open neural-tube defects. An isolated low estriol level is usually correlated with compromised uteroplacental perfusion and frequently associated with fetal death. A low estriol level in the context of normal fetal sonography and growth, after exclusion of placental sulfatase deficiency and Smith-Lemli-Opitz syndrome, should raise the suspicion of deficient fetal steroidogenesis, which leads to decreased production of adrenal dehydroepiandrosterone sulfate. We describe 2 brothers with adrenal insufficiency resulting from IAD. The parents are first cousins whose first son is healthy. During the pregnancy of the second son, who died at the age of 7 weeks as a result of presumed cardiomyopathy, a low estriol level on the TMST was ignored because of a normal fetal ultrasound. In the third pregnancy, a low level was found again, and the mother was referred to our tertiary center. Ultrasonography revealed no abnormalities, and karyotype was normal. Normal levels of steroid sulfatase activity and 7-dehydrocholesterol ruled out X-linked ichthyosis and Smith-Lemli-Opitz syndrome, respectively. Postnatally, basal and stimulated cortisol and ACTH levels were low. Other pituitary functions were normal, suggesting the diagnosis of IAD. The patient was treated with a stress dose of hydrocortisone on day 2 of life, which was tapered to a maintenance dose. At the time of this writing, he was 7 months old, with normal growth and development. Recently, loss-of-function mutations in the human TPIT gene were detected in autosomal recessive IAD. TPIT is a cell-restricted T-box transcription factor that is important for the terminal differentiation of pituitary corticotrophs. Therefore, we performed molecular analysis of the TPIT gene, which revealed a new mutation (IVS4+1G>A) that affects the first nucleotide of the splice site at the 5' end of the fourth intron. This stop codon probably leads to loss of TPIT function by nonsense-mediated mRNA decay, as it does for other TPIT nonsense mutations. We recommend that pregnant women with an isolated low estriol level of unexplained etiology be referred for additional evaluation by a multidisciplinary team that includes a geneticist and pediatric endocrinologist. Prompt ACTH testing in the first postnatal days will allow for early diagnosis. The immediate institution of glucocorticoid therapy, with proper instructions for stress management, can prevent unnecessary neonatal death secondary to an easily treatable disease.

Nitric oxide levels in preterm and term infants and in premature infants with bacteremia

OBJECTIVE

To determine the serum nitric oxide levels in healthy neonates and in infants with bacteremia.

METHODS

We performed a prospective study in a tertiary neonatal intensive care unit. The serum nitric oxide levels were measured in all infants at birth (basal) and in the infected neonates also on the first 2 days of bacteremia.

RESULTS

Thirty-three neonates (10 term, 23 preterm) were included. Eleven preterm infants (mean gestational age 27 weeks) had bacteremia. The main blood culture isolates included coagulase-negative staphylococci (n=4), Klebsiella pneumoniae (n=3), and Escherichia coli (n=3). The serum nitric oxide levels increased during infection in 10 infants (p <0.008). The mean nitric oxide level before infection was 44 microM and during infection 96 microM (p=0.008). In the healthy babies, the mean nitric oxide level was 26 microM in those with a gestational age <27 weeks, 44 microM in those born between 28 and 36 weeks of gestation, and 63 microM in term infants.

CONCLUSIONS

Bacteremic preterm infants produce significantly higher amounts of nitric oxide. The basal nitric oxide levels at birth may be correlated with gestational age.

Hemophagocytic lymphohistiocytosis associated with visceral leishmaniasis

A 2-year-old child presented with fever and hepatosplenomegaly. Laboratory findings showed pancytopenia, hypertriglyceridemia, hyperferritinemia, and high levels of soluble-IL2 receptors. Initial bone marrow aspiration and biopsy revealed mild hemophagocytosis. A diagnosis of hemophagocytic lymphohistiocytosis was made and appropriate treatment was begun. Repeated marrow aspiration performed because of lack of clinical response revealed Leishmania amastigotes in macrophages in addition to active hemophagocytosis. Treatment with liposomal amphotericin resulted with rapid recovery. Visceral leishmaniasis should be considered in the differential diagnosis of hemophagocytic syndrome.

Clinical and laboratory impact of coagulase-negative staphylococci bacteremia in preterm infants

A retrospective evaluation of the clinical and laboratory impact of coagulase-negative staphylococci (CONS) bacteremia in preterm infants was carried out. The study population included all preterm infants (n = 31) in whom two or more blood cultures were positive for CONS within a period of 4 d, with negative blood cultures 1 wk before and 1 wk after the CONS bacteremia. Clinical manifestations and the results of laboratory tests 7 d before and after the positive blood cultures, and on the first day of sepsis, were recorded and compared. During CONS bacteremia, the infants demonstrated apnoea and bradycardia (88%) and a need for oxygen (59%) and ventilatory support (69%). Significant laboratory findings were leukopenia below 5,000 cells/mm3 (12%), leukocytosis above 30,000 cells/mm3 (39%), and thrombocytopenia below 150,000/mm3 (25%). These clinical and laboratory manifestations differed significantly during the bacteremia infection compared with the week before and after.

CONCLUSION

CONS bacteremia is a clinically significant infection in preterm infants, causing episodes of apnoea and bradycardia, and a need for ventilatory support.

Time reversal of ultrafast waveforms by wave mixing of spectrally decomposed waves

Two different realizations of time-reversal experiments of ultrafast waveforms are carried out in real time by use of four-wave mixing arrangements of spectrally decomposed waves. The first, conventional, method is based on phase conjugation of the waveform's spectrum and achieves time reversal of real amplitude waveforms. The second arrangement of the spectrally decomposed waves spatially inverts the waveform's spectrum with respect to the optical axis of the processor and achieves true time reversal for complex-amplitude ultrafast waveforms. We compare and contrast these two real-time techniques.

Significance of sporadic deceleration during antepartum testing in term pregnancies

We have investigated the significance of single sporadic deceleration during reactive nonstress testing in normal pregnancies at term. A prospective study was performed during a 1-year period including 4742 nonstress tests performed between the 38th and 42nd weeks of pregnancy in patients referred to our department for antepartum testing and without any complication or pathology. Nonstress test (NST) was carried out with the patient lying on her left side, and was defined as reactive if at least two accelerations of 15 beats/min (bpm) or more lasting 15 sec were observed in a 20-min period. Sporadic deceleration was defined as a decrease in the fetal heart rate to less than 90 bpm or a decrease of 40 bpm below the baseline, lasting at least 2 min. The sporadic deceleration was considered as single when only one appeared in the first 20 min of monitoring and repeated when observed again once in at least one subsequent monitoring. Thirty-four cases of single sporadic deceleration were observed among women with reactive NST. In 14 cases there were repeated sporadic decelerations. The patients were divided into two groups according to the presence or absence of repeated decelerations. Outcomes of patients with repeated sporadic decelerations were compared with a group of 34 patients where sporadic decelerations were not observed during the antepartum testing. A significantly higher percentage of pathological fetal heart rate traces during labor were observed in the group of repeated decelerations. In conclusion the presence of repeated sporadic decelerations during a reactive NST suggests that the cause of cord compromise is persistent and recurrent cord compression is possible. Therefore, in these cases an increased fetal risk could be expected.

Intravenous leiomyomatosis with cardiac involvement in a pregnant woman

Intravenous leiomyomatosis is a rare benign neoplasm that commonly grows into the pelvic veins and the inferior vena cava and, rarely, the right side of the heart. We report the first case of intravenous leiomyomatosis with cardiac involvement in a pregnant woman. The treatment of choice is surgical resection in two steps.