Inspired by a patient
Vetrini F, McKee S, Rosenfeld JA, Suri M, Lewis AM, Nugent KM, Roeder E, Littlejohn RO, Holder S, Zhu W, Alaimo JT, Graham B, Harris JM, Gibson JB, Pastore M, McBride KL, Komara M, Al-Gazali L, Al Shamsi A, Fanning EA, Wierenga KJ, Scott DA, Ben-Neriah Z, Meiner V, Cassuto H, Elpeleg O, Lloyd Holder J Jr, Burrage LC, Seaver LH, Van Maldergem L, Mahida S, Soul JS, Marlatt M, Matyakhina L, Vogt J, Gold JA, Park SM, Varghese V, Lampe AK, Kumar A, Lees M, Holder-Espinasse M, McConnell V, Bernhard B, Blair E, Harrison V; DDD study; Muzny DM, Gibbs RA, Elsea SH, Posey JE, Bi W, Lalani S, Xia F, Yang Y, Eng CM, Lupski JR, Liu P. Correction to: De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome. Genome Med. 2019 Mar 25;11(1):16. doi: 10.1186/s13073-019-0630-1. Erratum for: Genome Med. 2019 Feb 28;11(1):12. doi: 10.1186/s13073-019-0623-0. PMID: 30909959; PMCID: PMC6434874.
Abstract
Background: Neurodevelopmental disorders are genetically and phenotypically heterogeneous encompassing developmental delay (DD), intellectual disability (ID), autism spectrum disorders (ASDs), structural brain abnormalities, and neurological manifestations with variants in a large number of genes (hundreds) associated. To date, a few de novo mutations potentially disrupting TCF20 function in patients with ID, ASD, and hypotonia have been reported. TCF20 encodes a transcriptional co-regulator structurally related to RAI1, the dosage-sensitive gene responsible for Smith-Magenis syndrome (deletion/haploinsufficiency) and Potocki-Lupski syndrome (duplication/triplosensitivity).
Methods: Genome-wide analyses by exome sequencing (ES) and chromosomal microarray analysis (CMA) identified individuals with heterozygous, likely damaging, loss-of-function alleles in TCF20. We implemented further molecular and clinical analyses to determine the inheritance of the pathogenic variant alleles and studied the spectrum of phenotypes.
Results: We report 25 unique inactivating single nucleotide variants/indels (1 missense, 1 canonical splice-site variant, 18 frameshift, and 5 nonsense) and 4 deletions of TCF20. The pathogenic variants were detected in 32 patients and 4 affected parents from 31 unrelated families. Among cases with available parental samples, the variants were de novo in 20 instances and inherited from 4 symptomatic parents in 5, including in one set of monozygotic twins. Two pathogenic loss-of-function variants were recurrent in unrelated families. Patients presented with a phenotype characterized by developmental delay, intellectual disability, hypotonia, variable dysmorphic features, movement disorders, and sleep disturbances.
Conclusions: TCF20 pathogenic variants are associated with a novel syndrome manifesting clinical characteristics similar to those observed in Smith-Magenis syndrome. Together with previously described cases, the clinical entity of TCF20-associated neurodevelopmental disorders (TAND) emerges from a genotype-driven perspective.
Torti E, Keren B, Palmer EE, Zhu Z, Afenjar A, Anderson IJ, Andrews MV, Atkinson C, Au M, Berry SA, Bowling KM, Boyle J, Buratti J, Cathey SS, Charles P, Cogne B, Courtin T, Escobar LF, Finley SL, Graham JM Jr, Grange DK, Heron D, Hewson S, Hiatt SM, Hibbs KA, Jayakar P, Kalsner L, Larcher L, Lesca G, Mark PR, Miller K, Nava C, Nizon M, Pai GS, Pappas J, Parsons G, Payne K, Putoux A, Rabin R, Sabatier I, Shinawi M, Shur N, Skinner SA, Valence S, Warren H, Whalen S, Crunk A, Douglas G, Monaghan KG, Person RE, Willaert R, Solomon BD, Juusola J. Variants in TCF20 in neurodevelopmental disability: description of 27 new patients and review of literature. Genet Med. 2019 Sep;21(9):2036-2042. doi: 10.1038/s41436-019-0454-9. Epub 2019 Feb 11. PMID: 30739909; PMCID: PMC7171701.
Abstract
Purpose: To define the clinical characteristics of patients with variants in TCF20, we describe 27 patients, 26 of whom were identified via exome sequencing. We compare detailed clinical data with 17 previously reported patients.
Methods: Patients were ascertained through molecular testing laboratories performing exome sequencing (and other testing) with orthogonal confirmation; collaborating referring clinicians provided detailed clinical information.
Results: The cohort of 27 patients all had novel variants, and ranged in age from 2 to 68 years. All had developmental delay/intellectual disability. Autism spectrum disorders/autistic features were reported in 69%, attention disorders or hyperactivity in 67%, craniofacial features (no recognizable facial gestalt) in 67%, structural brain anomalies in 24%, and seizures in 12%. Additional features affecting various organ systems were described in 93%. In a majority of patients, we did not observe previously reported findings of postnatal overgrowth or craniosynostosis, in comparison with earlier reports.
Conclusion: We provide valuable data regarding the prognosis and clinical manifestations of patients with variants in TCF20.
Zhou J, Hamdan H, Yalamanchili HK, Pang K, Pohodich AE, Lopez J, Shao Y, Oses-Prieto JA, Li L, Kim W, Durham MA, Bajikar SS, Palmer DJ, Ng P, Thompson ML, Bebin EM, Müller AJ, Kuechler A, Kampmeier A, Haack TB, Burlingame AL, Liu Z, Rasband MN, Zoghbi HY. Disruption of MeCP2-TCF20 complex underlies distinct neurodevelopmental disorders. Proc Natl Acad Sci U S A. 2022 Jan 25;119(4):e2119078119. doi: 10.1073/pnas.2119078119. PMID: 35074918; PMCID: PMC8794850.
Abstract
MeCP2 is associated with Rett syndrome (RTT), MECP2 duplication syndrome, and a number of conditions with isolated features of these diseases, including autism, intellectual disability, and motor dysfunction. MeCP2 is known to broadly bind methylated DNA, but the precise molecular mechanism driving disease pathogenesis remains to be determined. Using proximity-dependent biotinylation (BioID), we identified a transcription factor 20 (TCF20) complex that interacts with MeCP2 at the chromatin interface. Importantly, RTT-causing mutations in MECP2 disrupt this interaction. TCF20 and MeCP2 are highly coexpressed in neurons and coregulate the expression of key neuronal genes. Reducing Tcf20 partially rescued the behavioral deficits caused by MECP2 overexpression, demonstrating a functional relationship between MeCP2 and TCF20 in MECP2 duplication syndrome pathogenesis. We identified a patient exhibiting RTT-like neurological features with a missense mutation in the PHF14 subunit of the TCF20 complex that abolishes the MeCP2-PHF14-TCF20 interaction. Our data demonstrate the critical role of the MeCP2-TCF20 complex for brain function.
Schäfgen J, Cremer K, Becker J, Wieland T, Zink AM, Kim S, Windheuser IC, Kreiß M, Aretz S, Strom TM, Wieczorek D, Engels H. De novo nonsense and frameshift variants of TCF20 in individuals with intellectual disability and postnatal overgrowth. Eur J Hum Genet. 2016 Dec;24(12):1739-1745. doi: 10.1038/ejhg.2016.90. Epub 2016 Jul 20. PMID: 27436265; PMCID: PMC5117939.
Abstract
Recently, germline variants of the transcriptional co-regulator gene TCF20 have been implicated in the aetiology of autism spectrum disorders (ASD). However, the knowledge about the associated clinical picture remains fragmentary. In this study, two individuals with de novo TCF20 sequence variants were identified in a cohort of 313 individuals with intellectual disability of unknown aetiology, which was analysed by whole exome sequencing using a child-parent trio design. Both detected variants - one nonsense and one frameshift variant - were truncating. A comprehensive clinical characterisation of the patients yielded mild intellectual disability, postnatal tall stature and macrocephaly, obesity and muscular hypotonia as common clinical signs while ASD was only present in one proband. The present report begins to establish the clinical picture of individuals with de novo nonsense and frameshift variants of TCF20 which includes features such as proportionate overgrowth and muscular hypotonia. Furthermore, intellectual disability/developmental delay seems to be fully penetrant amongst known individuals with de novo nonsense and frameshift variants of TCF20, whereas ASD is shown to be incompletely penetrant. The transcriptional co-regulator gene TCF20 is hereby added to the growing number of genes implicated in the aetiology of both ASD and intellectual disability. Furthermore, such de novo variants of TCF20 may represent a novel differential diagnosis in the overgrowth syndrome spectrum.
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