@article {580, title = {De novo and inherited TCF20 pathogenic variants are associated with intellectual disability, dysmorphic features, hypotonia, and neurological impairments with similarities to Smith-Magenis syndrome.}, journal = {Genome Med}, volume = {11}, year = {2019}, month = {2019 02 28}, pages = {12}, 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.

}, keywords = {Adolescent, Child, Child, Preschool, Craniofacial Abnormalities, Developmental Disabilities, Female, Humans, INDEL Mutation, Infant, Intellectual Disability, Male, Muscle Hypotonia, Smith-Magenis Syndrome, Transcription Factors, Young Adult}, issn = {1756-994X}, doi = {10.1186/s13073-019-0623-0}, author = {Vetrini, Francesco and McKee, Shane and Rosenfeld, Jill A and Suri, Mohnish and Lewis, Andrea M and Nugent, Kimberly Margaret and Roeder, Elizabeth and Littlejohn, Rebecca O and Holder, Sue and Zhu, Wenmiao and Alaimo, Joseph T and Graham, Brett and Harris, Jill M and Gibson, James B and Pastore, Matthew and McBride, Kim L and Komara, Makanko and Al-Gazali, Lihadh and Al Shamsi, Aisha and Fanning, Elizabeth A and Wierenga, Klaas J and Scott, Daryl A and Ben-Neriah, Ziva and Meiner, Vardiella and Cassuto, Hanoch and Elpeleg, Orly and Holder, J Lloyd and Burrage, Lindsay C and Seaver, Laurie H and Van Maldergem, Lionel and Mahida, Sonal and Soul, Janet S and Marlatt, Margaret and Matyakhina, Ludmila and Vogt, Julie and Gold, June-Anne and Park, Soo-Mi and Varghese, Vinod and Lampe, Anne K and Kumar, Ajith and Lees, Melissa and Holder-Espinasse, Muriel and McConnell, Vivienne and Bernhard, Birgitta and Blair, Ed and Harrison, Victoria and Muzny, Donna M and Gibbs, Richard A and Elsea, Sarah H and Posey, Jennifer E and Bi, Weimin and Lalani, Seema and Xia, Fan and Yang, Yaping and Eng, Christine M and Lupski, James R and Liu, Pengfei} } @article {41, title = {Nonrecurrent PMP22-RAI1 contiguous gene deletions arise from replication-based mechanisms and result in Smith-Magenis syndrome with evident peripheral neuropathy.}, journal = {Hum Genet}, volume = {135}, year = {2016}, month = {2016 Oct}, pages = {1161-74}, abstract = {

Hereditary neuropathy with liability to pressure palsies (HNPP) and Smith-Magenis syndrome (SMS) are genomic disorders associated with deletion copy number variants involving chromosome 17p12 and 17p11.2, respectively. Nonallelic homologous recombination (NAHR)-mediated recurrent deletions are responsible for the majority of HNPP and SMS cases; the rearrangement products encompass the key dosage-sensitive genes PMP22 and RAI1, respectively, and result in haploinsufficiency for these genes. Less frequently, nonrecurrent genomic rearrangements occur at this locus. Contiguous gene duplications encompassing both PMP22 and RAI1, i.e., PMP22-RAI1 duplications, have been investigated, and replication-based mechanisms rather than NAHR have been proposed for these rearrangements. In the current study, we report molecular and clinical characterizations of six subjects with the reciprocal phenomenon of deletions spanning both genes, i.e., PMP22-RAI1 deletions. Molecular studies utilizing high-resolution array comparative genomic hybridization and breakpoint junction sequencing identified mutational signatures that were suggestive of replication-based mechanisms. Systematic clinical studies revealed features consistent with SMS, including features of intellectual disability, speech and gross motor delays, behavioral problems and ocular abnormalities. Five out of six subjects presented clinical signs and/or objective electrophysiologic studies of peripheral neuropathy. Clinical profiling may improve the clinical management of this unique group of subjects, as the peripheral neuropathy can be more severe or of earlier onset as compared to SMS patients having the common recurrent deletion. Moreover, the current study, in combination with the previous report of PMP22-RAI1 duplications, contributes to the understanding of rare complex phenotypes involving multiple dosage-sensitive genes from a genetic mechanistic standpoint.

}, keywords = {Adolescent, Adult, Child, Child, Preschool, Chromosomes, Human, Pair 17, DNA Copy Number Variations, DNA Replication, Female, Gene Deletion, Haploinsufficiency, Homologous Recombination, Humans, Intellectual Disability, Male, Mutation, Myelin Proteins, Smith-Magenis Syndrome, Trans-Activators, Transcription Factors}, issn = {1432-1203}, doi = {10.1007/s00439-016-1703-5}, author = {Yuan, Bo and Neira, Juanita and Gu, Shen and Harel, Tamar and Liu, Pengfei and Brice{\~n}o, Ignacio and Elsea, Sarah H and G{\'o}mez, Alberto and Potocki, Lorraine and Lupski, James R} }