QRICH1 variants in Ververi-Brady syndrome-delineation of the genotypic and phenotypic spectrum.

Ververi-Brady syndrome (VBS, # 617982) is a rare developmental disorder, and loss-of-function variants in QRICH1 were implicated in its etiology. Furthermore, a recognizable phenotype was proposed comprising delayed speech, learning difficulties and dysmorphic signs. Here, we present four unrelated individuals with one known nonsense variant (c.1954C > T; p.[Arg652*]) and three novel de novo QRICH1 variants, respectively. These included two frameshift mutations (c.832_833del; p.(Ser278Leufs*25), c.1812_1813delTG; p.(Glu605Glyfs*25)) and interestingly one missense mutation (c.2207G > A; p.[Ser736Asn]), expanding the mutational spectrum. Enlargement of the cohort by these four individuals contributes to the delineation of the VBS phenotype and suggests expressive speech delay, moderate motor delay, learning difficulties/mild ID, mild microcephaly, short stature and notable social behavior deficits as clinical hallmarks. In addition, one patient presented with nephroblastoma. The possible involvement of QRICH1 in pediatric cancer assumes careful surveillance a key priority for outcome of these patients. Further research and enlargement of cohorts are warranted to learn about the genetic architecture and the phenotypic spectrum in more detail.

Biallelic mutation of human SLC6A6 encoding the taurine transporter TAUT is linked to early retinal degeneration.

We previously reported that inactivation of the transmembrane taurine transporter (TauT or solute carrier 6a6) causes early retinal degeneration in mice. Compatible with taurine's indispensability for cell volume homeostasis, protein stabilization, cytoprotection, antioxidation, and immuno- and neuromodulation, mice develop multisystemic dysfunctions (hearing loss; liver fibrosis; and behavioral, heart, and skeletal muscle abnormalities) later on. Here, by genetic, cell biologic, in vivo1H-magnetic resonance spectroscopy and molecular dynamics simulation studies, we conducted in-depth characterization of a novel disorder: human TAUT deficiency. Loss of TAUT function due to a homozygous missense mutation caused panretinal degeneration in 2 brothers. TAUTp.A78E still localized in the plasma membrane but is predicted to impact structural stabilization. 3H-taurine uptake by peripheral blood mononuclear cells was reduced by 95%, and taurine levels were severely reduced in plasma, skeletal muscle, and brain. Extraocular dysfunctions were not yet detected, but significantly increased urinary excretion of 8-oxo-7,8-dihydroguanosine indicated generally enhanced (yet clinically unapparent) oxidative stress and RNA oxidation, warranting continuous broad surveillance.-Preising, M. N., Görg, B., Friedburg, C., Qvartskhava, N., Budde, B. S., Bonus, M., Toliat, M. R., Pfleger, C., Altmüller, J., Herebian, D., Beyer, M., Zöllner, H. J., Wittsack, H.-J., Schaper, J., Klee, D., Zechner, U., Nürnberg, P., Schipper, J., Schnitzler, A., Gohlke, H., Lorenz, B., Häussinger, D., Bolz, H. J. Biallelic mutation of human SLC6A6 encoding the taurine transporter TAUT is linked to early retinal degeneration.

SON haploinsufficiency causes impaired pre-mRNA splicing of CAKUT genes and heterogeneous renal phenotypes.

Although genetic testing is increasingly used in clinical nephrology, a large number of patients with congenital abnormalities of the kidney and urinary tract (CAKUT) remain undiagnosed with current gene panels. Therefore, careful curation of novel genetic findings is key to improving diagnostic yields. We recently described a novel intellectual disability syndrome caused by de novo heterozygous loss-of-function mutations in the gene encoding the splicing factor SON. Here, we show that many of these patients, including two previously unreported, exhibit a wide array of kidney abnormalities. Detailed phenotyping of 14 patients with SON haploinsufficiency identified kidney anomalies in 8 patients, including horseshoe kidney, unilateral renal hypoplasia, and renal cysts. Recurrent urinary tract infections, electrolyte disturbances, and hypertension were also observed in some patients. SON knockdown in kidney cell lines leads to abnormal pre-mRNA splicing, resulting in decreased expression of several established CAKUT genes. Furthermore, these molecular events were observed in patient-derived cells with SON haploinsufficiency. Taken together, our data suggest that the wide spectrum of phenotypes in patients with a pathogenic SON mutation is a consequence of impaired pre-mRNA splicing of several CAKUT genes. We propose that genetic testing panels designed to diagnose children with a kidney phenotype should include the SON gene.

Lymphnode tuberculosis in a 4-year-old boy with relapsed ganglioneuroblastoma: a case report.

BACKGROUND: Mycobacterium tuberculosis (M. tuberculosis) disease is a generally well-known problem among immunocompromised adults and children. In pediatric oncology, only few cases of M. tuberculosis disease are reported so far. CASE PRESENTATION: We report a case of concomitant lymphnode tuberculosis in a 4-year-old German boy with relapsed ganglioneuroblastoma. 18 months after the initial diagnosis, relapse with new paravertebral lesions and new lesions in the left lower lobe of the lung and in the perihilar lymphnodes suspicious of metastases of the ganglioneuroblastoma were detected. While relapse in the tumor was confirmed, unexpectedly, pathologic examination revealed morphological diagnosis of lymphnode tuberculosis. The boy was of German background without previous history of tuberculosis exposure. Both, antituberculostatic and relapse treatment were immediately initiated. Three months on, MRI revealed regressive findings in the lung and lymphnodes and partial response in the tumor. The patient underwent second MiBG therapy and haploidentical stem cell transplantation. CONCLUSION: The diagnosis of lymphnode tuberculosis in a 4-year-old German boy with relapsed ganglioneuroblastoma was only made by chance, but most likely saved his life. Pediatric oncologist should be aware of tuberculosis as the incidence might increase over time and the timely diagnosis of a potentially preventable M. tuberculosis disease is irreplaceable. Further studies are needed to explore the incidence of M. tuberculosis infections and the value of IGRA, testing for latent tuberculosis infection prior to chemotherapy in children with underlying malignancies.

Age-related apparent diffusion coefficients of lumbar vertebrae in healthy children at 1.5 T.

BACKGROUND: Diffusion-weighted magnetic resonance imaging with apparent diffusion coefficient (ADC) calculation is important for detecting bone marrow pathologies. OBJECTIVE: To investigate age-related differences of lumbar vertebral body ADC to establish normal values for healthy children. MATERIALS AND METHODS: Forty-nine healthy children without any history of oncological or hematological diseases (10.2±4.7 years, range: 0-20 years) were included in this retrospective study. All magnetic resonance imaging (MRI) examinations were performed at 1.5 T and with similar scan parameters. The diffusion-weighted sequences were performed with b values of 50, 400 and 800 s/mm2. ADC values were measured by placing regions of interest at three different levels within each lumbar vertebral body (L1 to L5). ADC values were analyzed for different age groups (0-2 years, 3-6 years, 7-11 years, 12-14 years, 15-20 years), for each vertebral and intravertebral level. RESULTS: The mean ADC of the whole study group was 0.60±0.09 × 10-3 mm2/s. Children between the ages of 12 and 14 years had significantly higher ADC compared to the other age groups (P≤0.0003). ADC values were significantly higher in the 1st lumbar vertebral body compared to the other levels of the lumbar spine (P<0.005) with the exception of L5, and in the upper third of the vertebral bodies compared to the middle or lower thirds (P≤0.003). CONCLUSION: The age-, vertebral- and intravertebral level-dependent differences in ADC suggest a varying composition and cellularity in different age groups and in different locations.

Gadolinium Brain Deposition after Macrocyclic Gadolinium Administration: A Pediatric Case-Control Study.

Purpose To determine whether signal intensity (SI) in T1 sequences as a potential indicator of gadolinium deposition increases after repeated administration of the macrocyclic gadolinium-based contrast agents (GBCAs) gadoteridol and gadoterate meglumine in a pediatric cohort. Materials and Methods This retrospective case-control study of children with brain tumors who underwent nine or more contrast material-enhanced brain magnetic resonance (MR) imaging studies from 2008 to 2015 was approved by the local ethics board. Informed consent was obtained for MR imaging. Twenty-four case patients aged 5-18 years and appropriate control patients with nonpathologic MR neuroimaging findings (and no GBCA administration), matched for age and sex, were inculded. SI was measured on unenhanced T1-weighted MR images for the following five regions of interest (ROIs): the dentate nucleus (DN), pons, substantia nigra (SN), pulvinar thalami, and globus pallidus (GP). Paired t tests were used to compare SI and SI ratios (DN to pons, GP to thalamus) between case patients and control patients. Pearson correlations between relative signal changes and the number of GBCA administrations and total GBCA dose were calculated. Results The mean number of GBCA administrations was 14.2. No significant differences in mean SI for any ROI and no group differences were found when DN-to-pons and GP-to-pulvinar ratios were compared (DN-to-pons ratio in case patients: mean, 1.0083 ± 0.0373 [standard deviation]; DN-to-pons ratio in control patients: mean, 1.0183 ± 0.01917; P = .37; GP-to-pulvinar ratio in case patients: mean, 1.1335 ± 0.04528; and GP-to-pulvinar ratio in control patients: mean, 1.1141 ± 0.07058; P = .29). No correlation was found between the number of GBCA administrations or the total amount of GBCA administered and signal change for any ROI. (Number of GBCA applications: DN: r = -0.254, P = .31; pons: r = -0.097, P = .65; SN: r = -0.194, P = .38; GP: r = -0.175, P = .41; pulvinar: r = -0.067, P = .75; total amount of administered GBCA: DN: r = 0.091, P = .72; pons: r = 0.106, P = .62; SN: r = -0.165, P = .45; GP: r = 0.111, P = .61; pulvinar: r = 0.173, P = .42.) Conclusion Multiple intravenous administrations of these macrocyclic GBCAs in children were not associated with a measurable increase in SI in T1 sequences as an indicator of brain gadolinium deposition detectable by using MR imaging. Additional imaging and pathologic studies are needed to confirm these findings. © RSNA, 2017 Online supplemental material is available for this article.

Human thioredoxin 2 deficiency impairs mitochondrial redox homeostasis and causes early-onset neurodegeneration.

Thioredoxin 2 (TXN2; also known as Trx2) is a small mitochondrial redox protein essential for the control of mitochondrial reactive oxygen species homeostasis, apoptosis regulation and cell viability. Exome sequencing in a 16-year-old adolescent suffering from an infantile-onset neurodegenerative disorder with severe cerebellar atrophy, epilepsy, dystonia, optic atrophy, and peripheral neuropathy, uncovered a homozygous stop mutation in TXN2. Analysis of patient-derived fibroblasts demonstrated absence of TXN2 protein, increased reactive oxygen species levels, impaired oxidative stress defence and oxidative phosphorylation dysfunction. Reconstitution of TXN2 expression restored all these parameters, indicating the causal role of TXN2 mutation in disease development. Supplementation with antioxidants effectively suppressed cellular reactive oxygen species production, improved cell viability and mitigated clinical symptoms during short-term follow-up. In conclusion, our report on a patient with TXN2 deficiency suggests an important role of reactive oxygen species homeostasis for human neuronal maintenance and energy metabolism.

Neonatal encephalocardiomyopathy caused by mutations in VARS2.

VARS2 encodes a mitochondrial aminoacyl-tRNA-synthetase. Mutations in VARS2 have recently been identified as a cause of mitochondrial encephalomyopathy in three individuals. However, clinical information remained scarce. Exome sequencing lead us to identify compound heterozygous pathogenic VARS2 variants in a boy presenting with severe lactic acidosis, hypertrophic cardiomyopathy, epilepsy, and abnormalities on brain imaging including hypoplasia of corpus callosum and cerebellum as well as a massive lactate peak on MR-spectroscopy. Studies in patient-derived fibroblasts confirmed the functional relevance of the identified VARS2 variants. Our report expands the phenotypic spectrum associated with this rare mitochondrial defect, in that VARS2 deficiency may also cause severe neonatal presentations with cardiac involvement and structural brain abnormalities.

De novo PIK3R1 gain-of-function with recurrent sinopulmonary infections, long-lasting chronic CMV-lymphadenitis and microcephaly.

PIK3R1 (phosphoinositide-3-kinase, regulatory subunit 1) gain-of-function has recently been described in patients with recurrent sinopulmonary infections, chronic CMV-/EBV-infections, lymphoproliferation, and hypogammaglobulinemia. Here we report a 15-year-old boy with treatment refractory CMV lymphadenitis, severe combined immunodeficiency, microcephaly and a severe developmental defect of Th17 cells. To avoid poor outcome, hematopoietic stem cell transplantation (HSCT) was performed. Subsequently, whole exome sequencing revealed a de novo heterozygous G-to-C mutation (chr5: 5:67,589,663: G>C) at the splice donor site of the PIK3R1 gene. Our data suggest that PIK3R1 gain-of-function leads to developmental defects in helper and regulatory T-cell subsets, the latter expanding the immunological features of PIK3R1 gain-of-function. T-cell subsets play a critical role in the regulation of immune response against infectious agents and of autoimmunity and thus may be particularly accountable for the clinical phenotype of affected patients.

The many faces of paediatric mitochondrial disease on neuroimaging.

The knowledge about the genetic spectrum underlying paediatric mitochondrial diseases is rapidly growing. As a consequence, the range of neuroimaging findings associated with mitochondrial diseases became extremely broad. This has important implications for radiologists and clinicians involved in the care of these patients. Here, we provide a condensed overview of brain magnetic resonance imaging (MRI) findings in children with genetically confirmed mitochondrial diseases. The neuroimaging spectrum ranges from classical Leigh syndrome with symmetrical lesions in basal ganglia and/or brain stem to structural abnormalities including cerebellar hypoplasia and corpus callosum dysgenesis. We highlight that, although some imaging patterns can be suggestive of a genetically defined mitochondrial syndrome, brain MRI-based candidate gene prioritization is only successful in a subset of patients.

MRPS22 mutation causes fatal neonatal lactic acidosis with brain and heart abnormalities.

The mitochondrial ribosomes are required for the synthesis of mitochondrial DNA-encoded subunits of the oxidative phosphorylation (OXPHOS) system. Here, we present a neonate with fatal lactic acidosis and combined OXPHOS deficiency caused by a homozygous mutation in MRPS22, a gene encoding a mitochondrial ribosomal small subunit protein. Brain imaging revealed several structural abnormalities, including agenesis of the corpus callosum, multiple periventricular cysts, and suspected intracerebral calcifications. Moreover, echocardiography demonstrated atrial and ventricular septal defects as well as a coronary artery fistula. Our report expands the clinical spectrum of this rare mitochondrial disorder and confirms the severe clinical phenotype associated with this defect.

A novel homozygous Fas ligand mutation leads to early protein truncation, abrogation of death receptor and reverse signaling and a severe form of the autoimmune lymphoproliferative syndrome.

We report a novel type of mutation in the death ligand FasL that was associated with a severe phenotype of the autoimmune lymphoproliferative syndrome in two patients. A frameshift mutation in the intracellular domain led to complete loss of FasL expression. Cell death signaling via its receptor and reverse signaling via its intracellular domain were completely abrogated. In vitro lymphocyte proliferation induced by weak T cell receptor stimulation could be blocked and cell death was induced by engagement of FasL in T cells derived from healthy individuals and a heterozygous carrier, but not in FasL-deficient patient derived cells. Expression of genes implicated in lymphocyte proliferation and activation (CCND1, NFATc1, NF-κB1) was increased in FasL-deficient T cells and could not be downregulated by FasL engagement as in healthy cells. Our data thus suggest, that deficiency in FasL reverse signaling may contribute to the clinical lymphoproliferative phenotype of ALPS.

A guide to diagnosis and treatment of Leigh syndrome.

Leigh syndrome is a devastating neurodegenerative disease, typically manifesting in infancy or early childhood. However, also late-onset cases have been reported. Since its first description by Denis Archibald Leigh in 1951, it has evolved from a postmortem diagnosis, strictly defined by histopathological observations, to a clinical entity with indicative laboratory and radiological findings. Hallmarks of the disease are symmetrical lesions in the basal ganglia or brain stem on MRI, and a clinical course with rapid deterioration of cognitive and motor functions. Examinations of fresh muscle tissue or cultured fibroblasts are important tools to establish a biochemical and genetic diagnosis. Numerous causative mutations in mitochondrial and nuclear genes, encoding components of the oxidative phosphorylation system have been described in the past years. Moreover, dysfunctions in pyruvate dehydrogenase complex or coenzyme Q10 metabolism may be associated with Leigh syndrome. To date, there is no cure for affected patients, and treatment options are mostly unsatisfactory. Here, we review the most important clinical aspects of Leigh syndrome, and discuss diagnostic steps as well as treatment options.

Evaluation of the impact of organ-specific dose reduction on image quality in pediatric chest computed tomography.

BACKGROUND: Organ-specific dose reduction significantly reduces the radiation exposure of radiosensitive organs. OBJECTIVE: The purpose of this study was to assess the impact of a novel organ-specific dose reduction algorithm on image quality of pediatric chest CT. MATERIALS AND METHODS: We included 28 children (mean age 10.9 ± 4.8 years, range 3-18 years) who had contrast-enhanced chest CT on a 128-row scanner. CT was performed at 100 kV using automated tube current modulation and a novel organ-specific dose-reduction algorithm (XCare™; Siemens, Forchheim, Germany). Seven children had a previous chest CT performed on a 64-row scanner at 100 kV without organ-specific dose reduction. Subjective image quality was assessed using a five-point scale (1-not diagnostic; 5-excellent). Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were assessed in the descending aorta. RESULTS: Overall mean subjective image quality was 4.1 ± 0.6. In the subgroup of the seven children examined both with and without organ-specific dose reduction, subjective image quality was comparable (score 4.4 ± 0.5 with organ-specific dose reduction vs. 4.4 ± 0.7 without it; P > 0.05). There was no significant difference in mean signal-to-noise ratio and contrast-to-noise ratio with organ-specific dose reduction (38.3 ± 10.1 and 28.5 ± 8.7, respectively) and without the reduction (35.5 ± 8.5 and 26.5 ± 7.8, respectively) (P > 0.05). Volume computed tomography dose index (CTDIvol) and size-specific dose estimates did not differ significantly between acquisitions with the organ-specific dose reduction (1.7 ± 0.8 mGy) and without the reduction (1.7 ± 0.8 mGy) (P > 0.05). CONCLUSION: Organ-specific dose reduction does not have an impact on image quality of pediatric chest CT and can therefore be used in clinical practice to reduce radiation dose of radiosensitive organs such as breast and thyroid gland.

Regional deep hyperthermia for salvage treatment of children and adolescents with refractory or recurrent non-testicular malignant germ-cell tumours: an open-label, non-randomised, single-institution, phase 2 study.

BACKGROUND: Although the survival of children and adolescents with malignant germ-cell tumours has improved greatly in recent years, the outcome remains poor for those with refractory or recurrent malignant germ-cell tumours. We aimed to determine whether objective tumour response could be achieved in patients with refractory or recurrent malignant germ-cell tumours with PEI-regional deep hyperthermia as salvage treatment. METHODS: Patients with refractory or recurrent non-testicular malignant germ-cell tumours after standard cisplatin-based chemotherapy were treated prospectively with PEI chemotherapy (cisplatin 40 mg/m(2), delivered intravenously on days 1 and 4; etoposide 100 mg/m(2), intravenously on days 1-4; and ifosfamide 1800 mg/m(2), intravenously on days 1-4) plus simultaneous 1-h regional deep hyperthermia (41-43°C) on days 1 and 4. Patients received three to four treatment courses at 21-day intervals until residual tumour resection was possible; they subsequently received one or two additional courses of PEI-regional deep hyperthermia. Local radiotherapy was given for incompletely resected tumours. Chemotherapy and hyperthermia toxic effects were assessed using WHO grading. The primary endpoint was the proportion of patients who had an objective response as assessed with Response Evaluation Criteria in Solid Tumors version 1.0 guidelines. Secondary endpoints were the event-free survival and overall survival after 5 years. This ongoing PEI-regional deep hyperthermia study (Hyper-PEI protocol) is registered at the German Cancer Society, number 50-2732. FINDINGS: 44 patients aged 7 months to 21 years (median 2 years 7 months) with refractory or recurrent malignant germ-cell tumours (nine patients with poor response, 23 patients with first relapse, 12 patients with multiple relapses) were included in this study. We identified 34 yolk sac tumours, eight embryonal carcinomas, one choriocarcinoma, and one dysgerminoma by histology analysis. Of the 35 patients who had sufficient clinical and radiographical data available for response assessment, 30 (86%) had an objective response to treatment (16 patients had complete remission and 14 had partial remission). 5-year event-free survival was 62% (95% CI 45-75), and 5-year overall survival was 72% (95% CI 55-83). The median follow-up of surviving patients was 82 months (range 9-195). WHO grade 3-4 neutropenia and thrombocytopenia occurred in all 181 chemotherapy cycles. Granulocytopenic fever, which required intercurrent hospital admission, was noted in 29 (66%) of 44 patients after 53 (29%) of 181 courses. Five patients experienced treatment-related grade-3 acute renal toxic effects. INTERPRETATION: A multimodal strategy integrating PEI-regional deep hyperthermia and tumour resection with or without radiation can successfully treat children and adolescents with refractory or recurrent malignant non-testicular germ-cell tumours. The long-term prognosis of patients with poor response or after first relapse was almost similar to those receiving first-line treatment. This strategy merits further investigation. FUNDING: Deutsche Krebshilfe eV, Bonn, Elterninitiative Kinderkrebsklinik Düsseldorf eV, the Barbara and Hubertus-Trettnerstiftung, and the Marie Quendt Fund.

A novel inverted 17p13.3 microduplication disrupting PAFAH1B1 (LIS1) in a girl with syndromic lissencephaly.

We describe a female patient with mild lissencephaly (pachygyria), severe intellectual disability, and facial dysmorphisms with an inverted 1.4 Mb microduplication of chromosome 17p13.3. The 17p13.3 microduplication syndrome is associated with mild intellectual disabiltiy and contains, among others, the PAFAH1B1 (LIS1) gene, whereas microdeletions of the same segment cause Miller-Dieker syndrome (MDS) with severe to profound retardation. The duplication identified in our patient encompasses 29 genes, including CRK and YWHAE. The proximal breakpoint of the duplication is located in the first intron of the PAFAH1B1 gene. Analysis of total RNA showed that only one PAFAH1B1 allele is expressed. Therefore, this patient has a unique alteration: a duplication including YWHAE and CRK and haploinsufficiency of PAFAH1B1. Overexpression of YWHAE is associated with macrosomia, mild developmental delay, autism and facial dysmorphisms, and deletion of PAFAH1B1 alone leads to isolated lissencephaly (ILS). The patient described here shares features with MDS, but she is affected to a lesser degree. Her facial features are similar to MDS, and she has manifestations seen in other cases with YWHAE duplication.

Microbial communities related to volatile organic compound emission in automobile air conditioning units.

During operation of mobile air conditioning (MAC) systems in automobiles, malodours can occur. We studied the microbial communities found on contaminated heat exchanger fins of 45 evaporators from car MAC systems which were operated in seven different regions of the world and identified corresponding volatile organic compounds. Collected biofilms were examined by scanning electron microscopy and fluorescent in situ hybridization. The detected bacteria were loosely attached to the metal surface. Further analyses of the bacteria using PCR-based single-strand conformation polymorphism and sequencing of isolated 16S rRNA gene fragments identified highly divergent microbial communities with multiple members of the Alphaproteobacteriales, Methylobacteria were the prevalent bacteria. In addition, Sphingomonadales, Burkholderiales, Bacillales, Alcanivorax spp. and Stenotrophomonas spp. were found among many others depending on the location the evaporators were operated. Interestingly, typical pathogenic bacteria related to air conditioning systems including Legionella spp. were not found. In order to determine the nature of the chemical compounds produced by the bacteria, the volatile organic compounds were examined by closed loop stripping analysis and identified by combined gas chromatography/mass spectrometry. Sulphur compounds, i.e. di-, tri- and multiple sulphides, acetylthiazole, aromatic compounds and diverse substituted pyrazines were detected. Mathematical clustering of the determined microbial community structures against their origin identified a European/American/Arabic cluster versus two mainly tropical Asian clusters. Interestingly, clustering of the determined volatiles against the origin of the corresponding MAC revealed a highly similar pattern. A close relationship of microbial community structure and resulting malodours to the climate and air quality at the location of MAC operation was concluded.