De novo and inherited variants in ZNF292 underlie a neurodevelopmental disorder with features of autism spectrum disorder
Mirzaa GM, Chong JX, Piton A, Popp B, Foss K, Guo H, Harripaul R, Xia K, Scheck J, Aldinger KA, Sajan SA, Tang S, Bonneau D, Beck A, White J, Mahida S, Harris J, Smith-Hicks C, Hoyer J, Zweier C, Reis A, Thiel CT, Jamra RA, Zeid N, Yang A, Farach LS, Walsh L, Payne K, Rohena L, Velinov M, Ziegler A, Schaefer E, Gatinois V, Geneviève D, Simon MEH, Kohler J, Rotenberg J, Wheeler P, Larson A, Ernst ME, Akman CI, Westman R, Blanchet P, Schillaci LA, Vincent-Delorme C, Gripp KW, Mattioli F, Guyader GL, Gerard B, Mathieu-Dramard M, Morin G, Sasanfar R, Ayub M, Vasli N, Yang S, Person R, Monaghan KG, Nickerson DA, van Binsbergen E, Enns GM, Dries AM, Rowe LJ, Tsai ACH, Svihovec S, Friedman J, Agha Z, Qamar R, Rodan LH, Martinez-Agosto J, Ockeloen CW, Vincent M, Sunderland WJ, Bernstein JA; Undiagnosed Diseases Network,, Eichler EE, Vincent JB; University of Washington Center for Mendelian Genomics (UW-CMG),, Bamshad MJ.
Genet Med. 2020 Mar;22(3):538-546. doi: 10.1038/s41436-019-0693-9. Epub 2019 Nov 14.
PURPOSE: Intellectual disability (ID) and autism spectrum disorder (ASD) are genetically heterogeneous neurodevelopmental disorders. We sought to delineate the clinical, molecular, and neuroimaging spectrum of a novel neurodevelopmental disorder caused by variants in the zinc finger protein 292 gene (ZNF292).
METHODS: We ascertained a cohort of 28 families with ID due to putatively pathogenic ZNF292 variants that were identified via targeted and exome sequencing. Available data were analyzed to characterize the canonical phenotype and examine genotype-phenotype relationships.
RESULTS: Probands presented with ID as well as a spectrum of neurodevelopmental features including ASD, among others. All ZNF292 variants were de novo, except in one family with dominant inheritance. ZNF292 encodes a highly conserved zinc finger protein that acts as a transcription factor and is highly expressed in the developing human brain supporting its critical role in neurodevelopment.
CONCLUSION: De novo and dominantly inherited variants in ZNF292 are associated with a range of neurodevelopmental features including ID and ASD. The clinical spectrum is broad, and most individuals present with mild to moderate ID with or without other syndromic features. Our results suggest that variants in ZNF292 are likely a recurrent cause of a neurodevelopmental disorder manifesting as ID with or without ASD.
November 15, 2019
Validation of a host response test to distinguish bacterial and viral respiratory infection
Lydon EC, Henao R, Burke TW, Aydin M, Nicholson BP, Glickman SW, Fowler VG, Quackenbush EB, Cairns CB, Kingsmore SF, Jaehne AK, Rivers EP, Langley RJ, Petzold E, Ko ER, McClain MT, Ginsburg GS, Woods CW, Tsalik EL.
EBioMedicine. 2019 Oct;48:453-461. doi: 10.1016/j.ebiom.2019.09.040. Epub 2019 Oct 17.
BACKGROUND: Distinguishing bacterial and viral respiratory infections is challenging. Novel diagnostics based on differential host gene expression patterns are promising but have not been translated to a clinical platform nor extensively tested. Here, we validate a microarray-derived host response signature and explore performance in microbiology-negative and coinfection cases.
METHODS: Subjects with acute respiratory illness were enrolled in participating emergency departments. Reference standard was an adjudicated diagnosis of bacterial infection, viral infection, both, or neither. An 87-transcript signature for distinguishing bacterial, viral, and noninfectious illness was measured from peripheral blood using RT-PCR. Performance characteristics were evaluated in subjects with confirmed bacterial, viral, or noninfectious illness. Subjects with bacterial-viral coinfection and microbiologically-negative suspected bacterial infection were also evaluated. Performance was compared to procalcitonin.
FINDINGS: 151 subjects with microbiologically confirmed, single-etiology illness were tested, yielding AUROCs 0•85-0•89 for bacterial, viral, and noninfectious illness. Accuracy was similar to procalcitonin (88% vs 83%, p = 0•23) for bacterial vs. non-bacterial infection. Whereas procalcitonin cannot distinguish viral from non-infectious illness, the RT-PCR test had 81% accuracy in making this determination. Bacterial-viral coinfection was subdivided. Among 19 subjects with bacterial superinfection, the RT-PCR test identified 95% as bacterial, compared to 68% with procalcitonin (p = 0•13). Among 12 subjects with bacterial infection superimposed on chronic viral infection, the RT-PCR test identified 83% as bacterial, identical to procalcitonin. 39 subjects had suspected bacterial infection; the RT-PCR test identified bacterial infection more frequently than procalcitonin (82% vs 64%, p = 0•02).
INTERPRETATION: The RT-PCR test offered similar diagnostic performance to procalcitonin in some subgroups but offered better discrimination in others such as viral vs. non-infectious illness and bacterial/viral coinfection. Gene expression-based tests could impact decision-making for acute respiratory illness as well as a growing number of other infectious and non-infectious diseases.
October 22, 2019
Biallelic loss of GNAS in a patient with pediatric medulloblastoma
Mari J Tokita, Shareef Nahas, Benjamin Briggs, Denise M Malicki, Jill P Mesirov, Iris Anne C Reyes, Lauge Farnaes, Michael L Levy, Stephen F Kingsmore, David Dimmock, John R Crawford, Robert J Wechsler-Reya
Cold Spring Harb Mol Case Stud. 2019 Oct 23;5(5):a004572. doi: 10.1101/mcs.a004572. Print 2019 Oct.
Genome sequencing was performed on matched normal and tumor tissue from a 6.5-yr-old boy with a diagnosis of recurrent medulloblastoma. A pathogenic heterozygous c.432+1G>A canonical splice donor site variant in GNAS was detected on analysis of blood DNA. Analysis of tumor DNA showed the same splice variant along with copy-neutral loss of heterozygosity on Chromosome 20 encompassing GNAS, consistent with predicted biallelic loss of GNAS in the tumor specimen. This case strengthens the evidence implicating GNAS as a tumor-suppressor gene in medulloblastoma and highlights a scenario in which therapeutics targeting the cAMP pathway may be of great utility.
PMID:31624069 | PMC:PMC6824258 | DOI:10.1101/mcs.a004572
October 19, 2019
Dystonia-Ataxia with early handwriting deterioration in COQ8A mutation carriers: A case series and literature review
Galosi S, Barca E, Carrozzo R, Schirinzi T, Quinzii CM, Lieto M, Vasco G, Zanni G, Di Nottia M, Galatolo D, Filla A, Bertini E, Santorelli FM, Leuzzi V, Haas R, Hirano M, Friedman J.
Parkinsonism Relat Disord. 2019 Nov;68:8-16. doi: 10.1016/j.parkreldis.2019.09.015. Epub 2019 Sep 28.
Cerebellar ataxia is a hallmark of coenzyme Q10 (CoQ10) deficiency associated with COQ8A mutations. We present four patients, one with novel COQ8A pathogenic variants all with early, prominent handwriting impairment, dystonia and only mild ataxia. To better define the phenotypic spectrum and course of COQ8A disease, we review the clinical presentation and evolution in 47 reported cases. Individuals with COQ8A mutation display great clinical variability and unpredictable responses to CoQ10 supplementation. Onset is typically during infancy or childhood with ataxic features associated with developmental delay or regression. When disease onset is later in life, first symptoms can include: incoordination, epilepsy, tremor, and deterioration of writing. The natural history is characterized by a progression to a multisystem brain disease dominated by ataxia, with disease severity inversely correlated with age at onset. Six previously reported cases share with ours, a clinical phenotype characterized by slowly progressive or static writing difficulties, focal dystonia, and speech disorder, with only minimal ataxia. The combination of writing difficulty, dystonia and ataxia is a distinctive constellation that is reminiscent of a previously described clinical entity called Dystonia Ataxia Syndrome (DYTCA) and is an important clinical indicator of COQ8A mutations, even when ataxia is mild or absent.
PMID:31621627 | DOI:10.1016/j.parkreldis.2019.09.015
October 18, 2019
Genetic Neurologic DiseaseNeurogenomics
Recurrent homozygous damaging mutation in TMX2, encoding a protein disulfide isomerase, in four families with microlissencephaly
Ghosh SG, Wang L, Breuss MW, Green JD, Stanley V, Yang X, Ross D, Traynor BJ, Alhashem AM, Azam M, Selim L, Bastaki L, Elbastawisy HI, Temtamy S, Zaki M, Gleeson JG.
J Med Genet. 2020 Apr;57(4):274-282. doi: 10.1136/jmedgenet-2019-106409. Epub 2019 Oct 5.
BACKGROUND: Protein disulfide isomerase (PDI) proteins are part of the thioredoxin protein superfamily. PDIs are involved in the formation and rearrangement of disulfide bonds between cysteine residues during protein folding in the endoplasmic reticulum and are implicated in stress response pathways.
METHODS: Eight children from four consanguineous families residing in distinct geographies within the Middle East and Central Asia were recruited for study. All probands showed structurally similar microcephaly with lissencephaly (microlissencephaly) brain malformations. DNA samples from each family underwent whole exome sequencing, assessment for repeat expansions and confirmatory segregation analysis.
RESULTS: An identical homozygous variant in TMX2
(c.500G>A), encoding thioredoxin-related transmembrane protein 2, segregated with disease in all four families. This variant changed the last coding base of exon 6, and impacted mRNA stability. All patients presented with microlissencephaly, global developmental delay, intellectual disability and epilepsy. While TMX2
is an activator of cellular C9ORF72
repeat expansion toxicity, patients showed no evidence of C9ORF72
CONCLUSION: The TMX2
c.500G>A allele associates with recessive microlissencephaly, and patients show no evidence of C9ORF72
is the first PDI implicated in a recessive disease, suggesting a protein isomerisation defect in microlissencephaly.
October 7, 2019
Bi-allelic Loss of Human APC2, Encoding Adenomatous Polyposis Coli Protein 2, Leads to Lissencephaly, Subcortical Heterotopia, and Global Developmental Delay
Lee S, Chen DY, Zaki MS, Maroofian R, Houlden H, Di Donato N, Abdin D, Morsy H, Mirzaa GM, Dobyns WB, McEvoy-Venneri J, Stanley V, James KN, Mancini GMS, Schot R, Kalayci T, Altunoglu U, Karimiani EG, Brick L, Kozenko M, Jamshidi Y, Manzini MC, Beiraghi Toosi M, Gleeson JG.
Am J Hum Genet. 2019 Oct 3;105(4):844-853. doi: 10.1016/j.ajhg.2019.08.013.
Lissencephaly is a severe brain malformation in which failure of neuronal migration results in agyria or pachygyria and in which the brain surface appears unusually smooth. It is often associated with microcephaly, profound intellectual disability, epilepsy, and impaired motor abilities. Twenty-two genes are associated with lissencephaly, accounting for approximately 80% of disease. Here we report on 12 individuals with a unique form of lissencephaly; these individuals come from eight unrelated families and have bi-allelic mutations in APC2, encoding adenomatous polyposis coli protein 2. Brain imaging studies demonstrate extensive posterior predominant lissencephaly, similar to PAFAH1B1-associated lissencephaly, as well as co-occurrence of subcortical heterotopia posterior to the caudate nuclei, “ribbon-like” heterotopia in the posterior frontal region, and dysplastic in-folding of the mesial occipital cortex. The established role of APC2 in integrating the actin and microtubule cytoskeletons to mediate cellular morphological changes suggests shared function with other lissencephaly-encoded cytoskeletal proteins such as α-N-catenin (CTNNA2) and platelet-activating factor acetylhydrolase 1b regulatory subunit 1 (PAFAH1B1, also known as LIS1). Our findings identify APC2 as a radiographically distinguishable recessive form of lissencephaly.
October 5, 2019
A Randomized, Controlled Trial of the Analytic and Diagnostic Performance of Singleton and Trio, Rapid Genome and Exome Sequencing in Ill Infants
Kingsmore SF, Cakici JA, Clark MM, Gaughran M, Feddock M, Batalov S, Bainbridge MN, Carroll J, Caylor SA, Clarke C, Ding Y, Ellsworth K, Farnaes L, Hildreth A, Hobbs C, James K, Kint CI, Lenberg J, Nahas S, Prince L, Reyes I, Salz L, Sanford E, Schols P, Sweeney N, Tokita M, Veeraraghavan N, Watkins K, Wigby K, Wong T, Chowdhury S, Wright MS, Dimmock D; RCIGM Investigators.
Am J Hum Genet. 2019 Oct 3;105(4):719-733. doi: 10.1016/j.ajhg.2019.08.009. Epub 2019 Sep 26.
The second Newborn Sequencing in Genomic Medicine and Public Health study was a randomized, controlled trial of the effectiveness of rapid whole-genome or -exome sequencing (rWGS or rWES, respectively) in seriously ill infants with diseases of unknown etiology. Here we report comparisons of analytic and diagnostic performance. Of 1,248 ill inpatient infants, 578 (46%) had diseases of unknown etiology. 213 infants (37% of those eligible) were enrolled within 96 h of admission. 24 infants (11%) were very ill and received ultra-rapid whole-genome sequencing (urWGS). The remaining infants were randomized, 95 to rWES and 94 to rWGS. The analytic performance of rWGS was superior to rWES, including variants likely to affect protein function, and ClinVar pathogenic/likely pathogenic variants (p < 0.0001). The diagnostic performance of rWGS and rWES were similar (18 diagnoses in 94 infants [19%] versus 19 diagnoses in 95 infants [20%], respectively), as was time to result (median 11.0 versus 11.2 days, respectively). However, the proportion diagnosed by urWGS (11 of 24 [46%]) was higher than rWES/rWGS (p = 0.004) and time to result was less (median 4.6 days, p < 0.0001). The incremental diagnostic yield of reflexing to trio after negative proband analysis was 0.7% (1 of 147). In conclusion, rapid genomic sequencing can be performed as a first-tier diagnostic test in inpatient infants. urWGS had the shortest time to result, which was important in unstable infants, and those in whom a genetic diagnosis was likely to impact immediate management. Further comparison of urWGS and rWES is warranted because genomic technologies and knowledge of variant pathogenicity are evolving rapidly.
October 1, 2019
The mitochondrial carrier Citrin plays a role in regulating cellular energy during carcinogenesis
Rabinovich S, Silberman A, Adler L, Agron S, Levin-Zaidman S, Bahat A, Porat Z, Ben-Zeev E, Geva I, Itkin M, Malitsky S, Buchaklian A, Helbling D, Dimmock D, Erez A.
Oncogene. 2020 Jan;39(1):164-175. doi: 10.1038/s41388-019-0976-2. Epub 2019 Aug 28.
Citrin, encoded by SLC25A13 gene, is an inner mitochondrial transporter that is part of the malate-aspartate shuttle, which regulates the NAD+/NADH ratio between the cytosol and mitochondria. Citrullinemia type II (CTLN-II) is an inherited disorder caused by germline mutations in SLC25A13, manifesting clinically in growth failure that can be alleviated by dietary restriction of carbohydrates. The association of citrin with glycolysis and NAD+/NADH ratio led us to hypothesize that it may play a role in carcinogenesis. Indeed, we find that citrin is upregulated in multiple cancer types and is essential for supplementing NAD+ for glycolysis and NADH for oxidative phosphorylation. Consequently, citrin deficiency associates with autophagy, whereas its overexpression in cancer cells increases energy production and cancer invasion. Furthermore, based on the human deleterious mutations in citrin, we found a potential inhibitor of citrin that restricts cancerous phenotypes in cells. Collectively, our findings suggest that targeting citrin may be of benefit for cancer therapy.
August 30, 2019
Bi-allelic GOT2 Mutations Cause a Treatable Malate-Aspartate Shuttle-Related Encephalopathy
van Karnebeek CDM, Ramos RJ, Wen XY, Tarailo-Graovac M, Gleeson JG, Skrypnyk C, Brand-Arzamendi K, Karbassi F, Issa MY, van der Lee R, Drögemöller BI, Koster J, Rousseau J, Campeau PM, Wang Y, Cao F, Li M, Ruiter J, Ciapaite J, Kluijtmans LAJ, Willemsen MAAP, Jans JJ, Ross CJ, Wintjes LT, Rodenburg RJ, Huigen MCDG, Jia Z, Waterham HR, Wasserman WW, Wanders RJA, Verhoeven-Duif NM, Zaki MS, Wevers RA.
Am J Hum Genet. 2019 Sep 5;105(3):534-548. doi: 10.1016/j.ajhg.2019.07.015. Epub 2019 Aug 15.
Early-infantile encephalopathies with epilepsy are devastating conditions mandating an accurate diagnosis to guide proper management. Whole-exome sequencing was used to investigate the disease etiology in four children from independent families with intellectual disability and epilepsy, revealing bi-allelic GOT2 mutations. In-depth metabolic studies in individual 1 showed low plasma serine, hypercitrullinemia, hyperlactatemia, and hyperammonemia. The epilepsy was serine and pyridoxine responsive. Functional consequences of observed mutations were tested by measuring enzyme activity and by cell and animal models. Zebrafish and mouse models were used to validate brain developmental and functional defects and to test therapeutic strategies. GOT2 encodes the mitochondrial glutamate oxaloacetate transaminase. GOT2 enzyme activity was deficient in fibroblasts with bi-allelic mutations. GOT2, a member of the malate-aspartate shuttle, plays an essential role in the intracellular NAD(H) redox balance. De novo serine biosynthesis was impaired in fibroblasts with GOT2 mutations and GOT2-knockout HEK293 cells. Correcting the highly oxidized cytosolic NAD-redox state by pyruvate supplementation restored serine biosynthesis in GOT2-deficient cells. Knockdown of got2a in zebrafish resulted in a brain developmental defect associated with seizure-like electroencephalography spikes, which could be rescued by supplying pyridoxine in embryo water. Both pyridoxine and serine synergistically rescued embryonic developmental defects in zebrafish got2a morphants. The two treated individuals reacted favorably to their treatment. Our data provide a mechanistic basis for the biochemical abnormalities in GOT2 deficiency that may also hold for other MAS defects.
August 20, 2019
Agenesis of the putamen and globus pallidus caused by recessive mutations in the homeobox gene GSX2
De Mori R, Severino M, Mancardi MM, Anello D, Tardivo S, Biagini T, Capra V, Casella A, Cereda C, Copeland BR, Gagliardi S, Gamucci A, Ginevrino M, Illi B, Lorefice E, Musaev D, Stanley V, Micalizzi A, Gleeson JG, Mazza T, Rossi A, Valente EM.
Brain. 2019 Oct 1;142(10):2965-2978. doi: 10.1093/brain/awz247.
Basal ganglia are subcortical grey nuclei that play essential roles in controlling voluntary movements, cognition and emotion. While basal ganglia dysfunction is observed in many neurodegenerative or metabolic disorders, congenital malformations are rare. In particular, dysplastic basal ganglia are part of the malformative spectrum of tubulinopathies and X-linked lissencephaly with abnormal genitalia, but neurodevelopmental syndromes characterized by basal ganglia agenesis are not known to date. We ascertained two unrelated children (both female) presenting with spastic tetraparesis, severe generalized dystonia and intellectual impairment, sharing a unique brain malformation characterized by agenesis of putamina and globi pallidi, dysgenesis of the caudate nuclei, olfactory bulbs hypoplasia, and anomaly of the diencephalic-mesencephalic junction with abnormal corticospinal tract course. Whole-exome sequencing identified two novel homozygous variants, c.26C>A; p.(S9*) and c.752A>G; p.(Q251R) in the GSX2 gene, a member of the family of homeobox transcription factors, which are key regulators of embryonic development. GSX2 is highly expressed in neural progenitors of the lateral and median ganglionic eminences, two protrusions of the ventral telencephalon from which the basal ganglia and olfactory tubercles originate, where it promotes neurogenesis while negatively regulating oligodendrogenesis. The truncating variant resulted in complete loss of protein expression, while the missense variant affected a highly conserved residue of the homeobox domain, was consistently predicted as pathogenic by bioinformatic tools, resulted in reduced protein expression and caused impaired structural stability of the homeobox domain and weaker interaction with DNA according to molecular dynamic simulations. Moreover, the nuclear localization of the mutant protein in transfected cells was significantly reduced compared to the wild-type protein. Expression studies on both patients’ fibroblasts demonstrated reduced expression of GSX2 itself, likely due to altered transcriptional self-regulation, as well as significant expression changes of related genes such as ASCL1 and PAX6. Whole transcriptome analysis revealed a global deregulation in genes implicated in apoptosis and immunity, two broad pathways known to be involved in brain development. This is the first report of the clinical phenotype and molecular basis associated to basal ganglia agenesis in humans.
August 15, 2019