Endocannabinoid dysfunction in neurological disease: neuro-ocular DAGLA-related syndrome (NODRS)
Bainbridge MN, Mazumder A, Ogasawara D, Abou Jamra R, Bernard G, Bertini E, Burglen L, Cope H, Crawford A, Derksen A, Dure L, Gantz E, Koch-Hogrebe M, Hurst ACE, Mahida S, Marshall P, Micalizzi A, Novelli A, Peng H, Rodriguez D, Robbins SL, Rutledge SL, Scalise R, Schließke S, Shashi V, Srivastava S, Thiffault I, Topol S; Undiagnosed Disease Network, Qebibo L, Wieczorek D, Cravatt B, Haricharan S, Torkamani A, Friedman J.
Brain. 2022 Jun 23:awac223. doi: 10.1093/brain/awac223. Online ahead of print.
The endocannabinoid system is a highly conserved and ubiquitous signaling pathway with broad ranging effects. Despite critical pathway functions, gene variants have not previously been conclusively linked to human disease. We identified nine children from eight families with heterozygous, de novo truncating variants in the last exon of DAGLA with a neuro-ocular phenotype characterized by developmental delay, ataxia, and complex oculomotor abnormality. All children displayed paroxysms of nystagmus or eye deviation accompanied by compensatory head posture and worsened incoordination most frequently after waking. RNAseq showed clear expression of the truncated transcript and no differences were found between mutant and wild type DAGLA activity. Immunofluorescence staining of patient-derived fibroblasts and HEK cells expressing the mutant protein showed distinct perinuclear aggregation not detected in control samples. This report establishes truncating variants in the last DAGLA exon as the cause of a unique pediatric syndrome. Because enzymatic activity was preserved, the observed mis-localization of the truncated protein may account for the observed phenotype. Potential mechanisms include DAGLA haploinsufficiency at the plasma membrane or dominant negative effect. To our knowledge, this is the first report directly linking an endocannabinoid system component with human genetic disease and sets the stage for potential future therapeutic avenues.
June 23, 2022
Better and Faster is Cheaper
Sanford Kobayashi EF, Dimmock DP.
Hum Mutat. 2022 Jun 20. doi: 10.1002/humu.24422. Online ahead of print.
The rapid pace of advancement in genomic sequencing technology has recently reached a new milestone, with a record-setting time to molecular diagnosis of a mere eight hours. The catalyst behind this achievement is the accumulation of evidence indicating that quicker results more often make an impact on patient care and lead to healthcare cost savings. Herein, we review the diagnostic and clinical utility of rapid whole genome and rapid whole exome sequencing, the associated reduction in healthcare costs, and the relationship between these outcome measures and time-to-diagnosis. This article is protected by copyright. All rights reserved.
June 20, 2022
RPM for NICU and PICUrWGS
The Role of Genome Sequencing in Neonatal Intensive Care Units
Kingsmore SF, Cole FS.
Annu Rev Genomics Hum Genet. 2022 Jun 8. doi: 10.1146/annurev-genom-120921-103442. Online ahead of print.
Genetic diseases disrupt the functionality of an infant’s genome during fetal-neonatal adaptation and represent a leading cause of neonatal and infant mortality in the United States. Due to disease acuity, gene locus and allelic heterogeneity, and overlapping and diverse clinical phenotypes, diagnostic genome sequencing in neonatal intensive care units has required the development of methods to shorten turnaround times and improve genomic interpretation. From 2012 to 2021, 31 clinical studies documented the diagnostic and clinical utility of first-tier rapid or ultrarapid whole-genome sequencing through cost-effective identification of pathogenic genomic variants that change medical management, suggest new therapeutic strategies, and refine prognoses. Genomic diagnosis also permits prediction of reproductive recurrence risk for parents and surviving probands. Using implementation science and quality improvement, deployment of a genomic learning healthcare system will contribute to a reduction of neonatal and infant mortality through the integration of genome sequencing into best-practice neonatal intensive care. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
June 8, 2022
Infant MortalityRPM for NICU and PICUrWGS
A phenotypic spectrum of autism is attributable to the combined effects of rare variants, polygenic risk and sex
Antaki D, Guevara J, Maihofer AX, Klein M, Gujral M, Grove J, Carey CE, Hong O, Arranz MJ, Hervas A, Corsello C, Vaux KK, Muotri AR, Iakoucheva LM, Courchesne E, Pierce K, Gleeson JG, Robinson EB, Nievergelt CM, Sebat J.
Nat Genet. 2022 Jun 2. doi: 10.1038/s41588-022-01064-5. Online ahead of print.
The genetic etiology of autism spectrum disorder (ASD) is multifactorial, but how combinations of genetic factors determine risk is unclear. In a large family sample, we show that genetic loads of rare and polygenic risk are inversely correlated in cases and greater in females than in males, consistent with a liability threshold that differs by sex. De novo mutations (DNMs), rare inherited variants and polygenic scores were associated with various dimensions of symptom severity in children and parents. Parental age effects on risk for ASD in offspring were attributable to a combination of genetic mechanisms, including DNMs that accumulate in the paternal germline and inherited risk that influences behavior in parents. Genes implicated by rare variants were enriched in excitatory and inhibitory neurons compared with genes implicated by common variants. Our results suggest that a phenotypic spectrum of ASD is attributable to a spectrum of genetic factors that impact different neurodevelopmental processes.
June 2, 2022
Coming in from the cold: overcoming the hostile immune microenvironment of medulloblastoma
Eisemann T, Wechsler-Reya RJ.
Genes Dev. 2022 May 1;36(9-10):514-532. doi: 10.1101/gad.349538.122.
Medulloblastoma is an aggressive brain tumor that occurs predominantly in children. Despite intensive therapy, many patients die of the disease, and novel therapies are desperately needed. Although immunotherapy has shown promise in many cancers, the low mutational burden, limited infiltration of immune effector cells, and immune-suppressive microenvironment of medulloblastoma have led to the assumption that it is unlikely to respond to immunotherapy. However, emerging evidence is challenging this view. Here we review recent preclinical and clinical studies that have identified mechanisms of immune evasion in medulloblastoma, and highlight possible therapeutic interventions that may give new hope to medulloblastoma patients and their families.
May 1, 2022
A genome-wide association study of obstructive heart defects among participants in the National Birth Defects Prevention Study
Rashkin SR, Cleves M, Shaw GM, Nembhard WN, Nestoridi E, Jenkins MM, Romitti PA, Lou XY, Browne ML, Mitchell LE, Olshan AF, Lomangino K, Bhattacharyya S, Witte JS, Hobbs CA; National Birth Defects Prevention Study.
Am J Med Genet A. 2022 Apr 22. doi: 10.1002/ajmg.a.62759. Online ahead of print.
Obstructive heart defects (OHDs) share common structural lesions in arteries and cardiac valves, accounting for ~25% of all congenital heart defects. OHDs are highly heritable, resulting from interplay among maternal exposures, genetic susceptibilities, and epigenetic phenomena. A genome-wide association study was conducted in National Birth Defects Prevention Study participants (Ndiscovery = 3978; Nreplication = 2507), investigating the genetic architecture of OHDs using transmission/disequilibrium tests (TDT) in complete case-parental trios (Ndiscovery_TDT = 440; Nreplication_TDT = 275) and case-control analyses separately in infants (Ndiscovery_CCI = 1635; Nreplication_CCI = 990) and mothers (case status defined by infant; Ndiscovery_CCM = 1703; Nreplication_CCM = 1078). In the TDT analysis, the SLC44A2 single nucleotide polymorphism (SNP) rs2360743 was significantly associated with OHD (pdiscovery = 4.08 × 10-9 ; preplication = 2.44 × 10-4 ). A CAPN11 SNP (rs55877192) was suggestively associated with OHD (pdiscovery = 1.61 × 10-7 ; preplication = 0.0016). Two other SNPs were suggestively associated (p < 1 × 10-6 ) with OHD in only the discovery sample. In the case-control analyses, no SNPs were genome-wide significant, and, even with relaxed thresholds ( × discovery < 1 × 10-5 and preplication < 0.05), only one SNP (rs188255766) in the infant analysis was associated with OHDs (pdiscovery = 1.42 × 10-6 ; preplication = 0.04). Additional SNPs with pdiscovery < 1 × 10-5 were in loci supporting previous findings but did not replicate. Overall, there was modest evidence of an association between rs2360743 and rs55877192 and OHD and some evidence validating previously published findings.
April 22, 2022
Somatic mosaicism reveals clonal distributions of neocortical development
Breuss MW, Yang X, Schlachetzki JCM, Antaki D, Lana AJ, Xu X, Chung C, Chai G, Stanley V, Song Q, Newmeyer TF, Nguyen A, O’Brien S, Hoeksema MA, Cao B, Nott A, McEvoy-Venneri J, Pasillas MP, Barton ST, Copeland BR, Nahas S, Van Der Kraan L, Ding Y; NIMH Brain Somatic Mosaicism Network, Glass CK, Gleeson JG.
Nature. 2022 Apr 20. doi: 10.1038/s41586-022-04602-7. Online ahead of print.
The structure of the human neocortex underlies species-specific traits and reflects intricate developmental programs. Here we sought to reconstruct processes that occur during early development by sampling adult human tissues. We analysed neocortical clones in a post-mortem human brain through a comprehensive assessment of brain somatic mosaicism, acting as neutral lineage recorders1,2. We combined the sampling of 25 distinct anatomic locations with deep whole-genome sequencing in a neurotypical deceased individual and confirmed results with 5 samples collected from each of three additional donors. We identified 259 bona fide mosaic variants from the index case, then deconvolved distinct geographical, cell-type and clade organizations across the brain and other organs. We found that clones derived after the accumulation of 90-200 progenitors in the cerebral cortex tended to respect the midline axis, well before the anterior-posterior or ventral-dorsal axes, representing a secondary hierarchy following the overall patterning of forebrain and hindbrain domains. Clones across neocortically derived cells were consistent with a dual origin from both dorsal and ventral cellular populations, similar to rodents, whereas the microglia lineage appeared distinct from other resident brain cells. Our data provide a comprehensive analysis of brain somatic mosaicism across the neocortex and demonstrate cellular origins and progenitor distribution patterns within the human brain.
April 20, 2022
Best practices for the interpretation and reporting of clinical whole genome sequencing
Austin-Tse CA, Jobanputra V, Perry DL, Bick D, Taft RJ, Venner E, Gibbs RA, Young T, Barnett S, Belmont JW, Boczek N, Chowdhury S, Ellsworth KA, Guha S, Kulkarni S, Marcou C, Meng L, Murdock DR, Rehman AU, Spiteri E, Thomas-Wilson A, Kearney HM, Rehm HL; Medical Genome Initiative*.
NPJ Genom Med. 2022 Apr 8;7(1):27. doi: 10.1038/s41525-022-00295-z.
Whole genome sequencing (WGS) shows promise as a first-tier diagnostic test for patients with rare genetic disorders. However, standards addressing the definition and deployment practice of a best-in-class test are lacking. To address these gaps, the Medical Genome Initiative, a consortium of leading health care and research organizations in the US and Canada, was formed to expand access to high quality clinical WGS by convening experts and publishing best practices. Here, we present best practice recommendations for the interpretation and reporting of clinical diagnostic WGS, including discussion of challenges and emerging approaches that will be critical to harness the full potential of this comprehensive test.
April 11, 2022
RPM for NICU and PICU
Efficacy of Caffeine in ADCY5-Related Dyskinesia: A Retrospective Study
Méneret A, Mohammad SS, Cif L, Doummar D, DeGusmao C, Anheim M, Barth M, Damier P, Demonceau N, Friedman J, Gallea C, Gras D, Gurgel-Giannetti J, Innes EA, Necpál J, Riant F, Sagnes S, Sarret C, Seliverstov Y, Paramanandam V, Shetty K, Tranchant C, Doulazmi M, Vidailhet M, Pringsheim T, Roze E.
Mov Disord. 2022 Apr 5. doi: 10.1002/mds.29006. Online ahead of print.
BACKGROUND: ADCY5-related dyskinesia is characterized by early-onset movement disorders. There is currently no validated treatment, but anecdotal clinical reports and biological hypotheses suggest efficacy of caffeine.
OBJECTIVE: The aim is to obtain further insight into the efficacy and safety of caffeine in patients with ADCY5-related dyskinesia.
METHODS: A retrospective study was conducted worldwide in 30 patients with a proven ADCY5 mutation who had tried or were taking caffeine for dyskinesia. Disease characteristics and treatment responses were assessed through a questionnaire.
RESULTS: Caffeine was overall well tolerated, even in children, and 87% of patients reported a clear improvement. Caffeine reduced the frequency and duration of paroxysmal movement disorders but also improved baseline movement disorders and some other motor and nonmotor features, with consistent quality-of-life improvement. Three patients reported worsening.
CONCLUSION: Our findings suggest that caffeine should be considered as a first-line therapeutic option in ADCY5-related dyskinesia. © 2022 International Parkinson and Movement Disorder Society.
April 5, 2022
Genetic Neurologic Disease
El-Hattab-Alkuraya syndrome caused by biallelic WDR45B pathogenic variants: further delineation of the phenotype and genotype
Almannai M, Marafi D, Abdel-Salam GMH, Zaki MS, Duan R, Calame D, Herman I, Levesque FSHA, Elbendary HM, Hegazy I, Chung WK, Kavus H, Saeidi K, Maroofian R, AlHashim A, Al-Otaibi A, Madhi AA, Aboalseood HM, Alasmari A, Houlden H, Gleeson JG, Hunter JV, Posey JE, Lupski JR, El-Hattab AW.
Clin Genet. 2022 Mar 23. doi: 10.1111/cge.14132. Online ahead of print.
Homozygous pathogenic variants in WDR45B were first identified in six subjects from three unrelated families with global development delay, refractory seizures, spastic quadriplegia, and brain malformations. Since the initial report in 2018, no further cases have been described. In this report, we present 12 additional individuals from seven unrelated families and their clinical, radiological, and molecular findings. Six different variants in WDR45B were identified, five of which are novel. Microcephaly and global developmental delay were observed in all subjects, and seizures and spastic quadriplegia in most. Common findings on brain imaging include cerebral atrophy, ex-vacuo ventricular dilatation, brainstem volume loss, and symmetric under-opercularization. El-Hattab-Alkuraya syndrome is associated with a consistent phenotype characterized by early onset cerebral atrophy resulting in microcephaly, developmental delay, spastic quadriplegia, and seizures. The phenotype appears to be more severe among individuals with loss-of-function variants whereas those with missense variants were less severely affected suggesting a potential genotype-phenotype correlation in this disorder. A brain imaging pattern emerges which is consistent among individuals with loss-of-function variants and could potentially alert the neuroradiologists or clinician to consider WDR45B-related El-Hattab-Alkuraya syndrome. This article is protected by copyright. All rights reserved.
March 23, 2022