@article {975, title = {Clinical presentation and evolution of Xia-Gibbs syndrome due to p.Gly375ArgfsTer3 variant in a patient from DR Congo (Central Africa).}, journal = {Am J Med Genet A}, volume = {185}, year = {2021}, month = {2021 03}, pages = {990-994}, abstract = {

Xia-Gibbs syndrome (XGS) is a very rare genetic condition. The clinical spectrum is very broad and variable. The phenotype and evolution in a Congolese boy with XGS have been reported. At 6 years he had speech delay, drooling, marked hyperactivity, attention deficit, aggressive behavior, and intellectual disability. Dysmorphological evaluation revealed strabismus, mild unilateral ptosis, uplifted ear lobes, flat philtrum, thin upper lip vermillion, high arched palate, and flat feet. Patient-only whole exome sequencing identified a known pathogenic frameshift variant in the AHDC1 gene [NM_001029882.3(AHDC1):c.1122dupC;(p.Gly375ArgfsTer3)]. The clinical follow-up revealed the deterioration of his fine motor skills and significant cerebellar phenotype including tremor, pes cavus, and gait instability at the age of 12 years. This patient was compared with three previously reported patients with the same variant but did not identify a consistent pattern in the evolution of symptoms with age.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.62049}, author = {Mubungu, Gerrye and Makay, Prince and Boujemla, Bouchra and Yanda, Stephane and Posey, Jennifer E and Lupski, James R and Bours, Vincent and Lukusa, Prosper and Devriendt, Koenraad and Lumaka, Aim{\'e}} } @article {770, title = {MN1 C-terminal truncation syndrome is a novel neurodevelopmental and craniofacial disorder with partial rhombencephalosynapsis.}, journal = {Brain}, volume = {143}, year = {2020}, month = {2020 01 01}, pages = {55-68}, abstract = {

MN1 encodes a transcriptional co-regulator without homology to other proteins, previously implicated in acute myeloid leukaemia and development of the palate. Large deletions encompassing MN1 have been reported in individuals with variable neurodevelopmental anomalies and non-specific facial features. We identified a cluster of de novo truncating mutations in MN1 in a cohort of 23 individuals with strikingly similar dysmorphic facial features, especially midface hypoplasia, and intellectual disability with severe expressive language delay. Imaging revealed an atypical form of rhombencephalosynapsis, a distinctive brain malformation characterized by partial or complete loss of the cerebellar vermis with fusion of the cerebellar hemispheres, in 8/10 individuals. Rhombencephalosynapsis has no previously known definitive genetic or environmental causes. Other frequent features included perisylvian polymicrogyria, abnormal posterior clinoid processes and persistent trigeminal artery. MN1 is encoded by only two exons. All mutations, including the recurrent variant p.Arg1295* observed in 8/21 probands, fall in the terminal exon or the extreme 3{\textquoteright} region of exon 1, and are therefore predicted to result in escape from nonsense-mediated mRNA decay. This was confirmed in fibroblasts from three individuals. We propose that the condition described here, MN1 C-terminal truncation (MCTT) syndrome, is not due to MN1 haploinsufficiency but rather is the result of dominantly acting C-terminally truncated MN1 protein. Our data show that MN1 plays a critical role in human craniofacial and brain development, and opens the door to understanding the biological mechanisms underlying rhombencephalosynapsis.

}, keywords = {Abnormalities, Multiple, Adolescent, Basilar Artery, Carotid Arteries, Cerebellar Vermis, Cerebellum, Child, Child, Preschool, Cohort Studies, Comparative Genomic Hybridization, Craniofacial Abnormalities, Female, Fibroblasts, Humans, Imaging, Three-Dimensional, Infant, Intellectual Disability, Language Development Disorders, Magnetic Resonance Imaging, Male, Middle Aged, Mutation, Nervous System Malformations, Nonsense Mediated mRNA Decay, Polymicrogyria, Real-Time Polymerase Chain Reaction, RNA-Seq, Syndrome, Tomography, X-Ray Computed, Trans-Activators, Tumor Suppressor Proteins, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1460-2156}, doi = {10.1093/brain/awz379}, author = {Mak, Christopher C Y and Doherty, Dan and Lin, Angela E and Vegas, Nancy and Cho, Megan T and Viot, G{\'e}raldine and Dimartino, Cl{\'e}mantine and Weisfeld-Adams, James D and Lessel, Davor and Joss, Shelagh and Li, Chumei and Gonzaga-Jauregui, Claudia and Zarate, Yuri A and Ehmke, Nadja and Horn, Denise and Troyer, Caitlin and Kant, Sarina G and Lee, Youngha and Ishak, Gisele E and Leung, Gordon and Barone Pritchard, Amanda and Yang, Sandra and Bend, Eric G and Filippini, Francesca and Roadhouse, Chelsea and Lebrun, Nicolas and Mehaffey, Michele G and Martin, Pierre-Marie and Apple, Benjamin and Millan, Francisca and Puk, Oliver and Hoffer, Mariette J V and Henderson, Lindsay B and McGowan, Ruth and Wentzensen, Ingrid M and Pei, Steven and Zahir, Farah R and Yu, Mullin and Gibson, William T and Seman, Ann and Steeves, Marcie and Murrell, Jill R and Luettgen, Sabine and Francisco, Elizabeth and Strom, Tim M and Amlie-Wolf, Louise and Kaindl, Angela M and Wilson, William G and Halbach, Sara and Basel-Salmon, Lina and Lev-El, Noa and Denecke, Jonas and Vissers, Lisenka E L M and Radtke, Kelly and Chelly, Jamel and Zackai, Elaine and Friedman, Jan M and Bamshad, Michael J and Nickerson, Deborah A and Reid, Russell R and Devriendt, Koenraad and Chae, Jong-Hee and Stolerman, Elliot and McDougall, Carey and Powis, Z{\"o}e and Bienvenu, Thierry and Tan, Tiong Y and Orenstein, Naama and Dobyns, William B and Shieh, Joseph T and Choi, Murim and Waggoner, Darrel and Gripp, Karen W and Parker, Michael J and Stoler, Joan and Lyonnet, Stanislas and Cormier-Daire, Val{\'e}rie and Viskochil, David and Hoffman, Trevor L and Amiel, Jeanne and Chung, Brian H Y and Gordon, Christopher T} } @article {947, title = {Whole exome sequencing in a large pedigree with DCM identifies a novel mutation in .}, journal = {Acta Cardiol}, volume = {75}, year = {2020}, month = {2020 Dec}, pages = {748-753}, abstract = {

Familial dilated cardiomyopathy (DCM) is genetically heterogeneous and is associated with mutations in at least 40 different genes. Apart from encoding the giant protein Titin, none of these genes have an expected diagnostic yield of more than 5\% complicating genetic diagnosis. Whole exome sequencing (WES) is a powerful alternative for the identification of the causal gene, however variant interpretation remains challenging. We report on WES in a large family with autosomal dominant DCM complicated by end stage heart failure and non-sustained ventricular arrhythmias in whom no causative mutation was identified using a targeted gene panel including 28 genes. WES was applied on 2 affected cousins. Stringent filtering of the identified genetic variants was performed including population variant frequencies, in silico analysis, orthologous and paralogous conservation. Subsequently Sanger sequencing was performed for 10 potential disease causing variants in order to confirm the presence of the variant and to evaluate co-segregation. Only one variant in exon 9 of the RBM20 gene (c.2714T > A, p.Met950Lys, NM_001334363) showed full co-segregation in the 7 affected family members resulting in a maximum 2-point LOD score of 2.1 and suggesting this as the pathogenic mutation responsible for the phenotype. Recently mutations in RBM20 have been linked to arrhythmogenic dilated cardiomyopathy caused by defective splicing of the giant sarcomere protein titin and abnormal calcium handling. We report the identification of a novel mutation in RBM20 by WES in a large pedigree with DCM.

}, issn = {1784-973X}, doi = {10.1080/00015385.2019.1674490}, author = {Robyns, Tomas and Willems, Rik and Van Cleemput, Johan and Jhangiani, Shalini and Muzny, Donna and Gibbs, Richard and Lupski, James R and Breckpot, Jeroen and Devriendt, Koenraad and Corveleyn, Anniek} } @article {521, title = {A comprehensive clinical and genetic study in 127 patients with ID in Kinshasa, DR Congo.}, journal = {Am J Med Genet A}, volume = {176}, year = {2018}, month = {2018 09}, pages = {1897-1909}, abstract = {

Pathogenic variants account for 4 to 41\% of patients with intellectual disability (ID) or developmental delay (DD). In Sub-Saharan Africa, the prevalence of ID is thought to be higher, but data in Central Africa are limited to some case reports. In addition, clinical descriptions of some syndromes are not available for this population. This study aimed at providing an estimate for the fraction of ID/DD for which an underlying etiological genetic cause may be elucidated and provide insights into their clinical presentation in special institutions in a Central African country. A total of 127 patients (33 females and 94 males, mean age 10.03 {\textpm} 4.68 years), were recruited from six institutions across Kinshasa. A clinical diagnosis was achieved in 44 but molecular confirmation was achieved in 21 of the 22 patients with expected genetic defect (95\% clinical sensitivity). Identified diseases included Down syndrome (15\%), submicroscopic copy number variants (9\%), aminoacylase deficiency (0.8\%), Partington syndrome in one patient (0.8\%) and his similarly affected brother, X-linked syndromic Mental Retardation type 33 (0.8\%), and two conditions without clear underlying molecular genetic etiologies (Oculo-Auriculo-Vertebral and Amniotic Bands Sequence). We have shown that genetic etiologies, similar to those reported in Caucasian subjects, are a common etiologic cause of ID in African patients from Africa. We have confirmed the diagnostic utility of clinical characterization prior to genetic testing. Finally, our clinical descriptions provide insights into the presentation of these genetic diseases in African patients.

}, issn = {1552-4833}, doi = {10.1002/ajmg.a.40382}, author = {Lumaka, Aim{\'e} and Race, Valerie and Peeters, Hilde and Corveleyn, Anniek and Coban-Akdemir, Zeynep and Jhangiani, Shalini N and Song, Xiaofei and Mubungu, Gerrye and Posey, Jennifer and Lupski, James R and Vermeesch, Joris R and Lukusa, Prosper and Devriendt, Koenraad} } @article {59, title = {Identification of Intellectual Disability Genes in Female Patients with a Skewed X-Inactivation Pattern.}, journal = {Hum Mutat}, volume = {37}, year = {2016}, month = {2016 08}, pages = {804-11}, abstract = {

Intellectual disability (ID) is a heterogeneous disorder with an unknown molecular etiology in many cases. Previously, X-linked ID (XLID) studies focused on males because of the hemizygous state of their X chromosome. Carrier females are generally unaffected because of the presence of a second normal allele, or inactivation of the mutant X chromosome in most of their cells (skewing). However, in female ID patients, we hypothesized that the presence of skewing of X-inactivation would be an indicator for an X chromosomal ID cause. We analyzed the X-inactivation patterns of 288 females with ID, and found that 22 (7.6\%) had extreme skewing (>90\%), which is significantly higher than observed in the general population (3.6\%; P~=~0.029). Whole-exome sequencing of 19 females with extreme skewing revealed causal variants in six females in the XLID genes DDX3X, NHS, WDR45, MECP2, and SMC1A. Interestingly, variants in genes escaping X-inactivation presumably cause both XLID and skewing of X-inactivation in three of these patients. Moreover, variants likely accounting for skewing only were detected in MED12, HDAC8, and TAF9B. All tested candidate causative variants were de novo events. Hence, extreme skewing is a good indicator for the presence of X-linked variants in female patients.

}, keywords = {Carrier Proteins, Cell Cycle Proteins, Chromosomal Proteins, Non-Histone, DEAD-box RNA Helicases, Exome, Female, Genetic Variation, Humans, Intellectual Disability, Methyl-CpG-Binding Protein 2, Nuclear Proteins, Sequence Analysis, DNA, X Chromosome Inactivation}, issn = {1098-1004}, doi = {10.1002/humu.23012}, author = {Fieremans, Nathalie and Van Esch, Hilde and Holvoet, Maureen and Van Goethem, Gert and Devriendt, Koenraad and Rosello, Monica and Mayo, Sonia and Martinez, Francisco and Jhangiani, Shalini and Muzny, Donna M and Gibbs, Richard A and Lupski, James R and Vermeesch, Joris R and Marynen, Peter and Froyen, Guy} } @article {256, title = {Mutations in PIEZO2 cause Gordon syndrome, Marden-Walker syndrome, and distal arthrogryposis type 5.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 May 01}, pages = {734-44}, abstract = {

Gordon syndrome (GS), or distal arthrogryposis type 3, is a rare, autosomal-dominant disorder characterized by cleft palate and congenital contractures of the hands and feet. Exome sequencing of five GS-affected families identified mutations in piezo-type mechanosensitive ion channel component 2 (PIEZO2) in each family. Sanger sequencing revealed PIEZO2 mutations in five of seven additional families studied (for a total of 10/12 [83\%] individuals), and nine families had an identical c.8057G>A (p.Arg2686His) mutation. The phenotype of GS overlaps with distal arthrogryposis type 5 (DA5) and Marden-Walker syndrome (MWS). Using molecular inversion probes for targeted sequencing to screen PIEZO2, we found mutations in 24/29 (82\%) DA5-affected families and one of two MWS-affected families. The presence of cleft palate was significantly associated with c.8057G>A (Fisher{\textquoteright}s exact test, adjusted p value < 0.0001). Collectively, although GS, DA5, and MWS have traditionally been considered separate disorders, our findings indicate that they are etiologically related and perhaps represent variable expressivity of the same condition.

}, keywords = {Abnormalities, Multiple, Arachnodactyly, Arthrogryposis, Blepharophimosis, Child, Child, Preschool, Cleft Palate, Clubfoot, Connective Tissue Diseases, Contracture, Exome, Female, Hand Deformities, Congenital, Humans, Ion Channels, Male, Mutation, Ophthalmoplegia, Pedigree, Retinal Diseases}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.03.015}, author = {McMillin, Margaret J and Beck, Anita E and Chong, Jessica X and Shively, Kathryn M and Buckingham, Kati J and Gildersleeve, Heidi I S and Aracena, Mariana I and Aylsworth, Arthur S and Bitoun, Pierre and Carey, John C and Clericuzio, Carol L and Crow, Yanick J and Curry, Cynthia J and Devriendt, Koenraad and Everman, David B and Fryer, Alan and Gibson, Kate and Giovannucci Uzielli, Maria Luisa and Graham, John M and Hall, Judith G and Hecht, Jacqueline T and Heidenreich, Randall A and Hurst, Jane A and Irani, Sarosh and Krapels, Ingrid P C and Leroy, Jules G and Mowat, David and Plant, Gordon T and Robertson, Stephen P and Schorry, Elizabeth K and Scott, Richard H and Seaver, Laurie H and Sherr, Elliott and Splitt, Miranda and Stewart, Helen and Stumpel, Constance and Temel, Sehime G and Weaver, David D and Whiteford, Margo and Williams, Marc S and Tabor, Holly K and Smith, Joshua D and Shendure, Jay and Nickerson, Deborah A and Bamshad, Michael J} }