@article {769, title = {Delineation of a Human Mendelian Disorder of the DNA Demethylation Machinery: TET3 Deficiency.}, journal = {Am J Hum Genet}, volume = {106}, year = {2020}, month = {2020 02 06}, pages = {234-245}, abstract = {

Germline pathogenic variants in chromatin-modifying enzymes are a common cause of pediatric developmental disorders. These enzymes catalyze reactions that regulate epigenetic inheritance via histone post-translational modifications and DNA methylation. Cytosine methylation (5-methylcytosine [5mC]) of DNA is the quintessential epigenetic mark, yet no human Mendelian disorder of DNA demethylation has yet been delineated. Here, we describe in detail a Mendelian disorder caused by the disruption of DNA demethylation. TET3 is a methylcytosine dioxygenase that initiates DNA demethylation during early zygote formation, embryogenesis, and neuronal differentiation and is intolerant to haploinsufficiency in mice and humans. We identify and characterize 11 cases of human TET3 deficiency in eight families with the common phenotypic features of intellectual disability and/or global developmental delay; hypotonia; autistic traits; movement disorders; growth abnormalities; and facial dysmorphism. Mono-allelic frameshift and nonsense variants in TET3 occur throughout the coding region. Mono-allelic and bi-allelic missense variants localize to conserved residues; all but one such variant occur within the catalytic domain, and most display hypomorphic function in an assay of catalytic activity. TET3 deficiency and other Mendelian disorders of the epigenetic machinery show substantial phenotypic overlap, including features of intellectual disability and abnormal growth, underscoring shared disease mechanisms.

}, keywords = {Adult, Amino Acid Sequence, Autistic Disorder, Child, Child, Preschool, Developmental Disabilities, Dioxygenases, DNA Demethylation, Embryonic Development, Female, Gene Expression Regulation, Developmental, Growth Disorders, Humans, Infant, Male, Middle Aged, Movement Disorders, Pedigree, Protein Conformation, Sequence Homology, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2019.12.007}, author = {Beck, David B and Petracovici, Ana and He, Chongsheng and Moore, Hannah W and Louie, Raymond J and Ansar, Muhammad and Douzgou, Sofia and Sithambaram, Sivagamy and Cottrell, Trudie and Santos-Cortez, Regie Lyn P and Prijoles, Eloise J and Bend, Renee and Keren, Boris and Mignot, Cyril and Nougues, Marie-Christine and {\~O}unap, Katrin and Reimand, Tiia and Pajusalu, Sander and Zahid, Muhammad and Saqib, Muhammad Arif Nadeem and Buratti, Julien and Seaby, Eleanor G and McWalter, Kirsty and Telegrafi, Aida and Baldridge, Dustin and Shinawi, Marwan and Leal, Suzanne M and Schaefer, G Bradley and Stevenson, Roger E and Banka, Siddharth and Bonasio, Roberto and Fahrner, Jill A} } @article {726, title = {PEHO syndrome caused by compound heterozygote variants in ZNHIT3 gene.}, journal = {Eur J Med Genet}, volume = {63}, year = {2020}, month = {2020 Feb}, pages = {103660}, abstract = {

PEHO syndrome is characterized by Progressive Encephalopathy with Edema, Hypsarrhythmia, and Optic atrophy, which was first described in Finnish patients. A homozygous missense substitution p.Ser31Leu in ZNHIT3 was recently identified as the primary cause of PEHO syndrome in Finland. Variants in ZNHIT3 have not been identified in patients with PEHO or PEHO-like syndrome in other populations. It has therefore been suggested that PEHO syndrome caused by ZNHIT3 variants does not occur outside of the Finnish population. We describe the first patient outside Finland who carries compound heterozygous variants in ZNHIT3 gene causing PEHO syndrome. Trio genome sequencing was carried out and the identified variants were confirmed by Sanger sequencing. The patient filled all diagnostic clinical criteria of PEHO syndrome. We identified biallelic missense variants in ZNHIT3 gene: the c.92C > T p.(Ser31Leu) variant (NM_004773.3), which is described previously as causing PEHO syndrome and the second novel variant c.41G > T p.(Cys14Phe). There are only eight heterozygous carriers of c.41G > T variant in the gnomAD database and it is predicted damaging by multiple in silico algorithms. The ZNHIT3-associated PEHO syndrome exists outside of the Finnish population.

}, keywords = {Brain Edema, Databases, Genetic, Edema, Epileptic Syndromes, Female, Finland, Heterozygote, Humans, Infant, Newborn, Mutation, Missense, Neurodegenerative Diseases, Nuclear Proteins, Optic Atrophy, Phenotype, Spasms, Infantile, Transcription Factors, Whole Exome Sequencing, Whole Genome Sequencing}, issn = {1878-0849}, doi = {10.1016/j.ejmg.2019.04.017}, author = {{\~O}unap, Katrin and Muru, Kai and {\~O}iglane-Shlik, Eve and Ilves, Pilvi and Pajusalu, Sander and Kuus, Imbi and Wojcik, Monica H and Reimand, Tiia} } @article {594, title = {Spatially clustering de novo variants in CYFIP2, encoding the cytoplasmic FMRP interacting protein 2, cause intellectual disability and seizures.}, journal = {Eur J Hum Genet}, volume = {27}, year = {2019}, month = {2019 May}, pages = {747-759}, abstract = {

CYFIP2, encoding the evolutionary highly conserved cytoplasmic FMRP interacting protein 2, has previously been proposed as a candidate gene for intellectual disability and autism because of its important role linking FMRP-dependent transcription regulation and actin polymerization via the WAVE regulatory complex (WRC). Recently, de novo variants affecting the amino acid p.Arg87 of CYFIP2 were reported in four individuals with epileptic encephalopathy. We here report 12 independent patients harboring a variety of de novo variants in CYFIP2 broadening the molecular and clinical spectrum of a novel CYFIP2-related neurodevelopmental disorder. Using trio whole-exome or -genome sequencing, we identified 12 independent patients carrying a total of eight distinct de novo variants in CYFIP2 with a shared phenotype of intellectual disability, seizures, and muscular hypotonia. We detected seven different missense variants, of which two occurred recurrently (p.(Arg87Cys) and p.(Ile664Met)), and a splice donor variant in the last intron for which we showed exon skipping in the transcript. The latter is expected to escape nonsense-mediated mRNA decay resulting in a truncated protein. Despite the large spacing in the primary structure, the variants spatially cluster in the tertiary structure and are all predicted to weaken the interaction with WAVE1 or NCKAP1 of the actin polymerization regulating WRC-complex. Preliminary genotype-phenotype correlation indicates a profound phenotype in p.Arg87 substitutions and a more variable phenotype in other alterations. This study evidenced a variety of de novo variants in CYFIP2 as a novel cause of mostly severe intellectual disability with seizures and muscular hypotonia.

}, issn = {1476-5438}, doi = {10.1038/s41431-018-0331-z}, author = {Zweier, Markus and Begemann, Ana{\"\i}s and McWalter, Kirsty and Cho, Megan T and Abela, Lucia and Banka, Siddharth and Behring, Bettina and Berger, Andrea and Brown, Chester W and Carneiro, Maryline and Chen, Jiani and Cooper, Gregory M and Finnila, Candice R and Guillen Sacoto, Maria J and Henderson, Alex and H{\"u}ffmeier, Ulrike and Joset, Pascal and Kerr, Bronwyn and Lesca, Gaetan and Leszinski, Gloria S and McDermott, John Henry and Meltzer, Meira R and Monaghan, Kristin G and Mostafavi, Roya and {\~O}unap, Katrin and Plecko, Barbara and Powis, Z{\"o}e and Purcarin, Gabriela and Reimand, Tiia and Riedhammer, Korbinian M and Schreiber, John M and Sirsi, Deepa and Wierenga, Klaas J and Wojcik, Monica H and Papuc, Sorina M and Steindl, Katharina and Sticht, Heinrich and Rauch, Anita} }