@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 {342, title = {MECR Mutations Cause Childhood-Onset Dystonia and Optic Atrophy, a Mitochondrial Fatty Acid Synthesis Disorder.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Dec 01}, pages = {1229-1244}, abstract = {

Mitochondrial fatty acid synthesis (mtFAS) is an evolutionarily conserved pathway essential for the function of the respiratory chain and several mitochondrial enzyme complexes. We report here a unique neurometabolic human disorder caused by defective mtFAS. Seven individuals from five unrelated families presented with childhood-onset dystonia, optic atrophy, and basal ganglia signal abnormalities on MRI. All affected individuals were found to harbor recessive mutations in MECR encoding the mitochondrial trans-2-enoyl-coenzyme A-reductase involved in human mtFAS. All six mutations are extremely rare in the general population, segregate with the disease in the families, and are predicted to be deleterious. The nonsense c.855T>G (p.Tyr285), c.247_250del (p.Asn83Hisfs4), and splice site c.830+2_830+3insT mutations lead to C-terminal truncation variants of MECR. The missense c.695G>A (p.Gly232Glu), c.854A>G (p.Tyr285Cys), and c.772C>T (p.Arg258Trp) mutations involve conserved amino acid residues, are located within the cofactor binding domain, and are predicted by structural analysis to have a destabilizing effect. Yeast modeling and complementation studies validated the pathogenicity of the MECR mutations. Fibroblast cell lines from affected individuals displayed reduced levels of both MECR and lipoylated proteins as well as defective respiration. These results suggest that mutations in MECR cause a distinct human disorder of the mtFAS pathway. The observation of decreased lipoylation raises the possibility of a potential therapeutic strategy.

}, keywords = {Basal Ganglia, Cells, Cultured, Child, Child, Preschool, Dystonic Disorders, Fatty Acids, Female, Fibroblasts, Genetic Complementation Test, Humans, Infant, Male, Mitochondria, Mitochondrial Diseases, Models, Molecular, Mutation, Mutation, Missense, Optic Atrophy, Oxidoreductases Acting on CH-CH Group Donors, Pedigree, RNA Splice Sites, Saccharomyces cerevisiae}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.09.021}, author = {Heimer, Gali and Ker{\"a}t{\"a}r, Juha M and Riley, Lisa G and Balasubramaniam, Shanti and Eyal, Eran and Pietik{\"a}inen, Laura P and Hiltunen, J Kalervo and Marek-Yagel, Dina and Hamada, Jeffrey and Gregory, Allison and Rogers, Caleb and Hogarth, Penelope and Nance, Martha A and Shalva, Nechama and Veber, Alvit and Tzadok, Michal and Nissenkorn, Andreea and Tonduti, Davide and Renaldo, Florence and Kraoua, Ichraf and Panteghini, Celeste and Valletta, Lorella and Garavaglia, Barbara and Cowley, Mark J and Gayevskiy, Velimir and Roscioli, Tony and Silberstein, Jonathon M and Hoffmann, Chen and Raas-Rothschild, Annick and Tiranti, Valeria and Anikster, Yair and Christodoulou, John and Kastaniotis, Alexander J and Ben-Zeev, Bruria and Hayflick, Susan J} } @article {44, title = {PEHO Syndrome May Represent Phenotypic Expansion at the Severe End of the Early-Onset Encephalopathies.}, journal = {Pediatr Neurol}, volume = {60}, year = {2016}, month = {2016 Jul}, pages = {83-7}, abstract = {

BACKGROUND: Progressive encephalopathy with edema, hypsarrhythmia and optic atrophy (PEHO) syndrome is a distinct neurodevelopmental disorder. Patients without optic nerve atrophy and brain imaging abnormalities but fulfilling other PEHO criteria are often described as a PEHO-like syndrome. The molecular bases of both clinically defined conditions remain unknown in spite of the widespread application of genome analyses in both clinic and research.

METHODS: We enrolled two patients with a prior diagnosis of PEHO and two individuals with PEHO-like syndrome. All four individuals subsequently underwent whole-exome sequencing and comprehensive genomic analysis.

RESULTS: We identified disease-causing mutations in known genes associated with neurodevelopmental disorders including GNAO1 and CDKL5 in two of four individuals. One patient with PEHO syndrome and a de novoGNAO1 mutation was found to have an additional de novo mutation in HESX1 that is associated with optic atrophy.

CONCLUSIONS: We hypothesize that PEHO and PEHO-like syndrome may represent a severe end of the spectrum of the early-onset encephalopathies and, in some instances, its complex phenotype may result from an aggregated effect of mutations at two loci.

}, keywords = {Brain Edema, Child, Child, Preschool, Female, GTP-Binding Protein alpha Subunits, Gi-Go, Humans, Infant, Male, Mutation, Neurodegenerative Diseases, Optic Atrophy, Phenotype, Protein Serine-Threonine Kinases, Spasms, Infantile}, issn = {1873-5150}, doi = {10.1016/j.pediatrneurol.2016.03.011}, author = {Gawlinski, Pawel and Posmyk, Renata and Gambin, Tomasz and Sielicka, Danuta and Chorazy, Monika and Nowakowska, Beata and Jhangiani, Shalini N and Muzny, Donna M and Bekiesinska-Figatowska, Monika and Bal, Jerzy and Boerwinkle, Eric and Gibbs, Richard A and Lupski, James R and Wiszniewski, Wojciech} } @article {21, title = {Recurrent De Novo and Biallelic Variation of ATAD3A, Encoding a Mitochondrial Membrane Protein, Results in Distinct Neurological Syndromes.}, journal = {Am J Hum Genet}, volume = {99}, year = {2016}, month = {2016 Oct 06}, pages = {831-845}, abstract = {

ATPase family AAA-domain containing protein 3A (ATAD3A) is a nuclear-encoded mitochondrial membrane protein implicated in mitochondrial dynamics, nucleoid organization, protein translation, cell growth, and cholesterol metabolism. We identified a recurrent de novo ATAD3A c.1582C>T (p.Arg528Trp) variant by whole-exome sequencing (WES) in five unrelated individuals with a core phenotype of global developmental delay, hypotonia, optic atrophy, axonal neuropathy, and hypertrophic cardiomyopathy. We also describe two families with biallelic variants in ATAD3A, including a homozygous variant in two siblings, and biallelic ATAD3A deletions mediated by nonallelic homologous recombination (NAHR) between ATAD3A and gene family members ATAD3B and ATAD3C. Tissue-specific overexpression of bor, the Drosophila mutation homologous to the human c.1582C>T (p.Arg528Trp) variant, resulted in a dramatic decrease in mitochondrial content, aberrant mitochondrial morphology, and increased autophagy. Homozygous null bor larvae showed a significant decrease of mitochondria, while overexpression of bor resulted in larger, elongated mitochondria. Finally, fibroblasts of an affected individual exhibited increased mitophagy. We conclude that the p.Arg528Trp variant functions through a dominant-negative mechanism that results in small mitochondria that trigger mitophagy, resulting in a reduction in mitochondrial content. ATAD3A variation represents an additional link between mitochondrial dynamics and recognizable neurological syndromes, as seen with MFN2, OPA1, DNM1L, and STAT2 mutations.

}, keywords = {Adenosine Triphosphatases, Adult, Alleles, Animals, ATPases Associated with Diverse Cellular Activities, Axons, Cardiomyopathies, Child, Child, Preschool, Developmental Disabilities, DNA Copy Number Variations, Drosophila melanogaster, Female, Fibroblasts, Homozygote, Humans, Infant, Infant, Newborn, Male, Membrane Proteins, Mitochondria, Mitochondrial Proteins, Muscle Hypotonia, Muscles, Mutation, Nervous System Diseases, Neurons, Optic Atrophy, Phenotype, Polymorphism, Single Nucleotide, Syndrome, Young Adult}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2016.08.007}, author = {Harel, Tamar and Yoon, Wan Hee and Garone, Caterina and Gu, Shen and Coban-Akdemir, Zeynep and Eldomery, Mohammad K and Posey, Jennifer E and Jhangiani, Shalini N and Rosenfeld, Jill A and Cho, Megan T and Fox, Stephanie and Withers, Marjorie and Brooks, Stephanie M and Chiang, Theodore and Duraine, Lita and Erdin, Serkan and Yuan, Bo and Shao, Yunru and Moussallem, Elie and Lamperti, Costanza and Donati, Maria A and Smith, Joshua D and McLaughlin, Heather M and Eng, Christine M and Walkiewicz, Magdalena and Xia, Fan and Pippucci, Tommaso and Magini, Pamela and Seri, Marco and Zeviani, Massimo and Hirano, Michio and Hunter, Jill V and Srour, Myriam and Zanigni, Stefano and Lewis, Richard Alan and Muzny, Donna M and Lotze, Timothy E and Boerwinkle, Eric and Gibbs, Richard A and Hickey, Scott E and Graham, Brett H and Yang, Yaping and Buhas, Daniela and Martin, Donna M and Potocki, Lorraine and Graziano, Claudio and Bellen, Hugo J and Lupski, James R} } @article {413, title = {Whole-exome sequencing identifies novel variants in PNPT1 causing oxidative phosphorylation defects and severe multisystem disease.}, journal = {Eur J Hum Genet}, volume = {25}, year = {2016}, month = {2016 01}, pages = {79-84}, abstract = {

Recent advances in next-generation sequencing strategies have led to the discovery of many novel disease genes. We describe here a non-consanguineous family with two affected boys presenting with early onset of severe axonal neuropathy, optic atrophy, intellectual disability, auditory neuropathy and chronic respiratory and gut disturbances. Whole-exome sequencing (WES) was performed on all family members and we identified compound heterozygous variants (c.[760C>A];[1528G>C];p.[(Gln254Lys);(Ala510Pro)] in the polyribonucleotide nucleotidyltransferase 1 (PNPT1) gene in both affected individuals. PNPT1 encodes the polynucleotide phosphorylase (PNPase) protein, which is involved in the transport of small RNAs into the mitochondria. These RNAs are involved in the mitochondrial translation machinery, responsible for the synthesis of mitochondrially encoded subunits of the oxidative phosphorylation (OXPHOS) complexes. Both PNPT1 variants are within highly conserved regions and predicted to be damaging. These variants resulted in quaternary defects in the PNPase protein and a clear reduction in protein and mRNA expression of PNPT1 in patient fibroblasts compared with control cells. Protein analysis of the OXPHOS complexes showed a significant reduction in complex I (CI), complex III (CIII) and complex IV (CIV). Enzyme activity of CI and CIV was clearly reduced in patient fibroblasts compared with controls along with a 33\% reduction in total mitochondrial protein synthesis. In vitro rescue experiments, using exogenous expression of wild-type PNPT1 in patient fibroblasts, ameliorated the deficiencies in the OXPHOS complex protein expression, supporting the likely pathogenicity of these variants and the importance of WES in efficiently identifying rare genetic disease genes.

}, keywords = {Axons, Exome, Exoribonucleases, High-Throughput Nucleotide Sequencing, Humans, Intellectual Disability, Male, Mitochondria, Mutation, Optic Atrophy, Oxidative Phosphorylation, Pedigree, Protein Structure, Quaternary}, issn = {1476-5438}, doi = {10.1038/ejhg.2016.128}, author = {Alodaib, Ahmad and Sobreira, Nara and Gold, Wendy A and Riley, Lisa G and Van Bergen, Nicole J and Wilson, Meredith J and Bennetts, Bruce and Thorburn, David R and Boehm, Corinne and Christodoulou, John} } @article {271, title = {NR2F1 mutations cause optic atrophy with intellectual disability.}, journal = {Am J Hum Genet}, volume = {94}, year = {2014}, month = {2014 Feb 06}, pages = {303-9}, abstract = {

Optic nerve atrophy and hypoplasia can be primary disorders or can result from trans-synaptic degeneration arising from cerebral visual impairment (CVI). Here we report six individuals with CVI and/or optic nerve abnormalities, born after an uneventful pregnancy and delivery, who have either de novo heterozygous missense mutations in NR2F1, also known as COUP-TFI, or deletions encompassing NR2F1. All affected individuals show mild to moderate intellectual impairment. NR2F1 encodes a nuclear receptor protein that regulates transcription. A reporter assay showed that missense mutations in the zinc-finger DNA-binding domain and the putative ligand-binding domain decrease NR2F1 transcriptional activity. These findings indicate that NR2F1 plays an important role in the neurodevelopment of the visual system and that its disruption can lead to optic atrophy with intellectual disability.

}, keywords = {Adolescent, Adult, Amino Acid Sequence, Child, Child, Preschool, COUP Transcription Factor I, DNA-Binding Proteins, Female, Genotype, Humans, Intellectual Disability, Male, Molecular Sequence Data, Mutation, Missense, Optic Atrophy, Phenotype, Young Adult, Zinc Fingers}, issn = {1537-6605}, doi = {10.1016/j.ajhg.2014.01.002}, author = {Bosch, Dani{\"e}lle G M and Boonstra, F Nienke and Gonzaga-Jauregui, Claudia and Xu, Mafei and de Ligt, Joep and Jhangiani, Shalini and Wiszniewski, Wojciech and Muzny, Donna M and Yntema, Helger G and Pfundt, Rolph and Vissers, Lisenka E L M and Spruijt, Liesbeth and Blokland, Ellen A W and Chen, Chun-An and Lewis, Richard A and Tsai, Sophia Y and Gibbs, Richard A and Tsai, Ming-Jer and Lupski, James R and Zoghbi, Huda Y and Cremers, Frans P M and de Vries, Bert B A and Schaaf, Christian P} }