Novel association of Dandy-Walker malformation with CAPN15 variants expands the phenotype of oculogastrointestinal neurodevelopmental syndrome
Beaman MM, Guidugli L, Hammer M, Barrows C, Gregor A, Lee S, Deak KL, McDonald MT, Jensen C, Zaki MS, Masri AT, Hobbs CA, Gleeson JG, Cohen JL.
Am J Med Genet A. 2023 Aug 19. doi: 10.1002/ajmg.a.63363. Online ahead of print.
Oculogastrointestinal neurodevelopmental syndrome has been described in seven previously published individuals who harbor biallelic pathogenic variants in the CAPN15 gene. Biallelic missense variants have been reported to demonstrate a phenotype of eye abnormalities and developmental delay, while biallelic loss of function variants exhibit phenotypes including microcephaly and craniofacial abnormalities, cardiac and genitourinary malformations, and abnormal neurologic activity. We report six individuals from three unrelated families harboring biallelic deleterious variants in CAPN15 with phenotypes overlapping those previously described for this disorder. Of the individuals affected, four demonstrate radiographic evidence of the classical triad of Dandy-Walker malformation including hypoplastic vermis, fourth ventricle enlargement, and torcular elevation. Cerebellar anomalies have not been previously reported in association with CAPN15-related disease. Here, we present three unrelated families with findings consistent with oculogastrointestinal neurodevelopmental syndrome and cerebellar pathology including Dandy-Walker malformation. To corroborate these novel clinical findings, we present supporting data from the mouse model suggesting an important role for this protein in normal cerebellar development. Our findings add six molecularly confirmed cases to the literature and additionally establish a new association of Dandy-Walker malformation with biallelic CAPN15 variants, thereby expanding the neurologic spectrum among patients affected by CAPN15-related disease.
August 19, 2023
The landscape of reported VUS in multi-gene panel and genomic testing: Time for a change
Rehm HL, Alaimo JT, Aradhya S, Bayrak-Toydemir P, Best H, Brandon R, Buchan JG, Chao EC, Chen E, Clifford J, Cohen ASA, Conlin LK, Das S, Davis KW, Gaudio DD, Del Viso F, DiVincenzo C, Eisenberg M, Guidugli L, Hammer MB, Harrison SM, Hatchell KE, Dyer LH, Hoang LU, Holt JM, Jobanputra V, Karbassi ID, Kearney HM, Kelly MA, Kelly JM, Kluge ML, Komala T, Kruszka P, Lau L, Lebo MS, Marshall CR, McKnight D, McWalter K, Meng Y, Nagan N, Neckelmann CS, Neerman N, Niu Z, Paolillo VK, Paolucci SA, Perry D, Pesaran T, Radtke K, Rasmussen KJ, Retterer K, Saunders CJ, Spiteri E, Stanley C, Szuto A, Taft RJ, Thiffault I, Thomas BC, Thomas-Wilson A, Thorpe E, Tidwell TJ, Towne MC, Zouk H; Medical Genome Initiative.
Genet Med. 2023 Jul 30:100947. doi: 10.1016/j.gim.2023.100947. Online ahead of print.
PURPOSE: Variants of uncertain significance (VUS) are a common result of diagnostic genetic testing and can be difficult to manage with potential misinterpretation and downstream costs, including time investment by clinicians. We investigated the rate of VUS reported on diagnostic testing via multi-gene panels (MGPs) and exome and genome sequencing (ES/GS) to measure the magnitude of uncertain results and explore ways to reduce their potentially detrimental impact.
METHODS: Rates of inconclusive results due to VUS were collected from over 1.5 million sequencing test results from 19 clinical laboratories in North America from 2020 – 2021.
RESULTS: We found a lower rate of inconclusive test results due to VUSs from ES/GS (22.5%) compared to MGPs (32.6%; p<0.0001). For MGPs, the rate of inconclusive results correlated with panel size. The use of trios reduced inconclusive rates (18.9% vs 27.6%; p<0.001) whereas the use of GS compared to ES had no impact (22.2% vs 22.6%; p=ns).
CONCLUSION: The high rate of VUS observed in diagnostic MGP testing warrants examining current variant reporting practices. We propose several approaches to reduce reported VUS rates, while directing clinician resources towards important VUS follow-up.
July 30, 2023
Report of two cases of Schaaf-Yang syndrome: Same genotype and different phenotype
Rodriguez AM, Schain K, Jayakar P, Wright MS, Chowdhury S, Salyakina D.
Clin Case Rep. 2023 Jul 30;11(8):e7753. doi: 10.1002/ccr3.7753. eCollection 2023 Aug.
We report two, genotypically identical but phenotypically distinct cases of Schaaf-Yang syndrome and propose the early use of Genome Sequencing in patients with nonspecific presentations to facilitate the early diagnosis of children with rare genetic diseases and improve overall health care outcomes.
July 30, 2023
Clinical Variants in C. elegans Expressing Human STXBP1 Reveals a Novel Class of Pathogenic Variants and Classifies Variants of Uncertain Significance
Hopkins CE, McCormick K, Brock T, Wood M, Helbig I, Mcbride K, Kim C, Lawson JA, Bainbridge MN
Genetics in Medicine Open (2023), doi: https://doi.org/10.1016/j.gimo.2023.100823.
Purpose: Modeling disease variants in animals is useful for drug discovery, understanding disease pathology, as well as classifying variants of uncertain significance (VUS) as pathogenic or benign.
Using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR), we performed a Whole-gene Humanized Animal Model (WHAM) procedure to replace the coding sequence of the animal model’s unc-18 ortholog with the coding sequence for the human STXBP1 gene. Next, we used CRISPR to introduce precise point variants in the WHAM-humanized STXBP1 locus from three clinical categories (benign, pathogenic, and VUS). 26 phenotypic features extracted from video recordings were used to train machine learning classifiers on 25 pathogenic and 32 benign variants.
Using multiple models, we were able to obtain a diagnostic sensitivity near 0.9. Twenty-three VUS were also interrogated and 8 of 23 (34.8%) were observed to be functionally abnormal. Interestingly, unsupervised clustering identified two distinct subsets of known pathogenic variants with distinct phenotypic features; Both p.Tyr75Cys and p.Arg406Cys cluster away from other variants and show an increase in swim speed compared to hSTXBP1 worms. This leads to the hypothesis that the mechanism of disease for these two variants may differ from most STXBP1-mutated patients and may account for some of the clinical heterogeneity observed in the patient population
July 25, 2023
Rapid Whole-Genomic Sequencing and a Targeted Neonatal Gene Panel in Infants With a Suspected Genetic Disorder
Maron JL, Kingsmore S, Gelb BD, Vockley J, Wigby K, Bragg J, Stroustrup A, Poindexter B, Suhrie K, Kim J, Diacovo T, Powell CM, Trembath A, Guidugli L, Ellsworth KA, Reed D, Kurfiss A, Breeze JL, Trinquart L, Davis JM
JAMA. 2023 Jul 11;330(2):161-169. doi: 10.1001/jama.2023.9350.
IMPORTANCE: Genomic testing in infancy guides medical decisions and can improve health outcomes. However, it is unclear whether genomic sequencing or a targeted neonatal gene-sequencing test provides comparable molecular diagnostic yields and times to return of results.
OBJECTIVE: To compare outcomes of genomic sequencing with those of a targeted neonatal gene-sequencing test.
DESIGN, SETTING, AND PARTICIPANTS: The Genomic Medicine for Ill Neonates and Infants (GEMINI) study was a prospective, comparative, multicenter study of 400 hospitalized infants younger than 1 year of age (proband) and their parents, when available, suspected of having a genetic disorder. The study was conducted at 6 US hospitals from June 2019 to November 2021.
EXPOSURE: Enrolled participants underwent simultaneous testing with genomic sequencing and a targeted neonatal gene-sequencing test. Each laboratory performed an independent interpretation of variants guided by knowledge of the patient’s phenotype and returned results to the clinical care team. Change in clinical management, therapies offered, and redirection of care was provided to families based on genetic findings from either platform.
MAIN OUTCOMES AND MEASURES: Primary end points were molecular diagnostic yield (participants with ≥1 pathogenic variant or variant of unknown significance), time to return of results, and clinical utility (changes in patient care).
RESULTS: A molecular diagnostic variant was identified in 51% of participants (n = 204; 297 variants identified with 134 being novel). Molecular diagnostic yield of genomic sequencing was 49% (95% CI, 44%-54%) vs 27% (95% CI, 23%-32%) with the targeted gene-sequencing test. Genomic sequencing did not report 19 variants found by the targeted neonatal gene-sequencing test; the targeted gene-sequencing test did not report 164 variants identified by genomic sequencing as diagnostic. Variants unidentified by the targeted genomic-sequencing test included structural variants longer than 1 kilobase (25.1%) and genes excluded from the test (24.6%) (McNemar odds ratio, 8.6 [95% CI, 5.4-14.7]). Variant interpretation by laboratories differed by 43%. Median time to return of results was 6.1 days for genomic sequencing and 4.2 days for the targeted genomic-sequencing test; for urgent cases (n = 107) the time was 3.3 days for genomic sequencing and 4.0 days for the targeted gene-sequencing test. Changes in clinical care affected 19% of participants, and 76% of clinicians viewed genomic testing as useful or very useful in clinical decision-making, irrespective of a diagnosis.
CONCLUSIONS AND RELEVANCE: The molecular diagnostic yield for genomic sequencing was higher than a targeted neonatal gene-sequencing test, but the time to return of routine results was slower. Interlaboratory variant interpretation contributes to differences in molecular diagnostic yield and may have important consequences for clinical management.
July 11, 2023
RPM for NICU and PICUrWGSrWGS Efficacy
Assessing Diversity in Newborn Genomic Sequencing Research Recruitment: Race/Ethnicity and Primary Spoken Language Variation in Eligibility, Enrollment, and Reasons for Declining
Cakici JA, Dimmock D, Caylor S, Gaughran M, Clarke C, Triplett C, Clark MM, Kingsmore SF, Bloss CS.
Clin Ther. 2023 Jul 8:S0149-2918(23)00220-5. doi: 10.1016/j.clinthera.2023.06.014. Online ahead of print.
PURPOSE: Diagnostic genomic research has the potential to directly benefit participants. This study sought to identify barriers to equitable enrollment of acutely ill newborns into a diagnostic genomic sequencing research study.
METHODS: We reviewed the 16-month recruitment process of a diagnostic genomic research study enrolling newborns admitted to the neonatal intensive care unit at a regional pediatric hospital that primarily serves English- and Spanish-speaking families. Differences in eligibility, enrollment, and reasons for not enrolling were examined as functions of race/ethnicity and primary spoken language.
FINDINGS: Of the 1248 newborns admitted to the neonatal intensive care unit, 46% (n = 580) were eligible, and 17% (n = 213) were enrolled. Of the 16 languages represented among the newborns’ families, 4 (25%) had translated consent documents. Speaking a language other than English or Spanish increased a newborn’s likelihood of being ineligible by 5.9 times (P < 0.001) after controlling for race/ethnicity. The main reason for ineligibility was documented as the clinical team declined having their patient recruited (41% [51 of 125]). This reason significantly affected families who spoke languages other than English or Spanish and was able to be remediated with training of the research staff. Stress (20% [18 of 90]) and the study intervention(s) (20% [18 of 90]) were the main reasons given for not enrolling.
IMPLICATIONS: This analysis of eligibility, enrollment, and reasons for not enrolling in a diagnostic genomic research study found that recruitment generally did not differ as a function of a newborn’s race/ethnicity. However, differences were observed depending on the parent’s primary spoken language. Regular monitoring and training can improve equitable enrollment into diagnostic genomic research. There are also opportunities at the federal level to improve access to those with limited English proficiency and thus decrease disparities in representation in research participation.
July 8, 2023
Newborn ScreeningRPM for NICU and PICU
Molecular portraits of cell cycle checkpoint kinases in cancer evolution, progression, and treatment responsiveness
Oropeza E, Seker S, Carrel S, Mazumder A, Lozano D, Jimenez A, VandenHeuvel SN, Noltensmeyer DA, Punturi NB, Lei JT, Lim B, Waltz SE, Raghavan SA, Bainbridge MN, Haricharan S.
Sci Adv. 2023 Jun 30;9(26):eadf2860. doi: 10.1126/sciadv.adf2860. Epub 2023 Jun 30.
Cell cycle dysregulation is prerequisite for cancer formation. However, it is unknown whether the mode of dysregulation affects disease characteristics. Here, we conduct comprehensive analyses of cell cycle checkpoint dysregulation using patient data and experimental investigations. We find that ATM mutation predisposes the diagnosis of primary estrogen receptor (ER)+/human epidermal growth factor (HER)2- cancer in older women. Conversely, CHK2 dysregulation induces formation of metastatic, premenopausal ER+/HER2- breast cancer (P = 0.001) that is treatment-resistant (HR = 6.15, P = 0.01). Lastly, while mutations in ATR alone are rare, ATR/TP53 co-mutation is 12-fold enriched over expected in ER+/HER2- disease (P = 0.002) and associates with metastatic progression (HR = 2.01, P = 0.006). Concordantly, ATR dysregulation induces metastatic phenotypes in TP53 mutant, not wild-type, cells. Overall, we identify mode of cell cycle dysregulation as a distinct event that determines subtype, metastatic potential, and treatment responsiveness, providing rationale for reconsidering diagnostic classification through the lens of the mode of cell cycle dysregulation..
June 30, 2023
Biallelic loss of function variants in WBP4 , encoding a spliceosome protein, result in a variable neurodevelopmental delay syndrome
Engal E, Oja KT, Maroofian R, Geminder O, Le TL, Mor E, Tzvi N, Elefant N, Zaki MS, Gleeson JG, Muru K, Pajusalu S, Wojcik MH, Pachat D, Elmaksoud MA, Jeong WC, Lee H, Bauer P, Zifarelli G, Houlden H, Elpeleg O, Gordon C, Harel T, Õunap K, Salton M, Mor-Shaked H.
medRxiv. 2023 Jun 27:2023.06.19.23291425. doi: 10.1101/2023.06.19.23291425. Preprint.
Over two dozen spliceosome proteins are involved in human diseases, also referred to as spliceosomopathies. WBP4 (WW Domain Binding Protein 4) is part of the early spliceosomal complex, and was not described before in the context of human pathologies. Ascertained through GeneMatcher we identified eleven patients from eight families, with a severe neurodevelopmental syndrome with variable manifestations. Clinical manifestations included hypotonia, global developmental delay, severe intellectual disability, brain abnormalities, musculoskeletal and gastrointestinal abnormalities. Genetic analysis revealed overall five different homozygous loss-of-function variants in WBP4 . Immunoblotting on fibroblasts from two affected individuals with different genetic variants demonstrated complete loss of protein, and RNA sequencing analysis uncovered shared abnormal splicing patterns, including enrichment for abnormalities of the nervous system and musculoskeletal system genes, suggesting that the overlapping differentially spliced genes are related to the common phenotypes of the probands. We conclude that biallelic variants in WBP4 cause a spliceosomopathy. Further functional studies are called for better understanding of the mechanism of pathogenicity.
June 27, 2023
BRAT1-related disorders: phenotypic spectrum and phenotype-genotype correlations from 97 patients
Engel C, Valence S, Delplancq G, Maroofian R, Accogli A, Agolini E, Alkuraya FS, Baglioni V, Bagnasco I, Becmeur-Lefebvre M, Bertini E, Borggraefe I, Brischoux-Boucher E, Bruel AL, Brusco A, Bubshait DK, Cabrol C, Cilio MR, Cornet MC, Coubes C, Danhaive O, Delague V, Denommé-Pichon AS, Di Giacomo MC, Doco-Fenzy M, Engels H, Cremer K, Gérard M, Gleeson JG, Heron D, Goffeney J, Guimier A, Harms FL, Houlden H, Iacomino M, Kaiyrzhanov R, Kamien B, Karimiani EG, Kraus D, Kuentz P, Kutsche K, Lederer D, Massingham L, Mignot C, Morris-Rosendahl D, Nagarajan L, Odent S, Ormières C, Partlow JN, Pasquier L, Penney L, Philippe C, Piccolo G, Poulton C, Putoux A, Rio M, Rougeot C, Salpietro V, Scheffer I, Schneider A, Srivastava S, Straussberg R, Striano P, Valente EM, Venot P, Villard L, Vitobello A, Wagner J, Wagner M, Zaki MS, Zara F, Lesca G, Yassaee VR, Miryounesi M, Hashemi-Gorji F, Beiraghi M, Ashrafzadeh F, Galehdari H, Walsh C, Novelli A, Tacke M, Sadykova D, Maidyrov Y, Koneev K, Shashkin C, Capra V, Zamani M, Van Maldergem L, Burglen L, Piard J.
Eur J Hum Genet. 2023 Jun 21. doi: 10.1038/s41431-023-01410-z. Online ahead of print.
BRAT1 biallelic variants are associated with rigidity and multifocal seizure syndrome, lethal neonatal (RMFSL), and neurodevelopmental disorder associating cerebellar atrophy with or without seizures syndrome (NEDCAS). To date, forty individuals have been reported in the literature. We collected clinical and molecular data from 57 additional cases allowing us to study a large cohort of 97 individuals and draw phenotype-genotype correlations. Fifty-nine individuals presented with BRAT1-related RMFSL phenotype. Most of them had no psychomotor acquisition (100%), epilepsy (100%), microcephaly (91%), limb rigidity (93%), and died prematurely (93%). Thirty-eight individuals presented a non-lethal phenotype of BRAT1-related NEDCAS phenotype. Seventy-six percent of the patients in this group were able to walk and 68% were able to say at least a few words. Most of them had cerebellar ataxia (82%), axial hypotonia (79%) and cerebellar atrophy (100%). Genotype-phenotype correlations in our cohort revealed that biallelic nonsense, frameshift or inframe deletion/insertion variants result in the severe BRAT1-related RMFSL phenotype (46/46; 100%). In contrast, genotypes with at least one missense were more likely associated with NEDCAS (28/34; 82%). The phenotype of patients carrying splice variants was variable: 41% presented with RMFSL (7/17) and 59% with NEDCAS (10/17).
June 21, 2023
A gene-based association test of interactions for maternal-fetal genotypes identifies genes associated with nonsyndromic congenital heart defects
Huang M, Lyu C, Liu N, Nembhard WN, Witte JS, Hobbs CA, Li M; National Birth Defects Prevention Study.
Genet Epidemiol. 2023 Jun 21. doi: 10.1002/gepi.22533. Online ahead of print.
The risk of congenital heart defects (CHDs) may be influenced by maternal genes, fetal genes, and their interactions. Existing methods commonly test the effects of maternal and fetal variants one-at-a-time and may have reduced statistical power to detect genetic variants with low minor allele frequencies. In this article, we propose a gene-based association test of interactions for maternal-fetal genotypes (GATI-MFG) using a case-mother and control-mother design. GATI-MFG can integrate the effects of multiple variants within a gene or genomic region and evaluate the joint effect of maternal and fetal genotypes while allowing for their interactions. In simulation studies, GATI-MFG had improved statistical power over alternative methods, such as the single-variant test and functional data analysis (FDA) under various disease scenarios. We further applied GATI-MFG to a two-phase genome-wide association study of CHDs for the testing of both common variants and rare variants using 947 CHD case mother-infant pairs and 1306 control mother-infant pairs from the National Birth Defects Prevention Study (NBDPS). After Bonferroni adjustment for 23,035 genes, two genes on chromosome 17, TMEM107 (p = 1.64e-06) and CTC1 (p = 2.0e-06), were identified for significant association with CHD in common variants analysis. Gene TMEM107 regulates ciliogenesis and ciliary protein composition and was found to be associated with heterotaxy. Gene CTC1 plays an essential role in protecting telomeres from degradation, which was suggested to be associated with cardiogenesis. Overall, GATI-MFG outperformed the single-variant test and FDA in the simulations, and the results of application to NBDPS samples are consistent with existing literature supporting the association of TMEM107 and CTC1 with CHDs.
June 21, 2023