@article {449, title = {Mutations in the MORC2 gene cause axonal Charcot-Marie-Tooth disease.}, journal = {Brain}, volume = {139}, year = {2016}, month = {2016 Jan}, pages = {62-72}, abstract = {

Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variants. The phenotype was variable and included patients with congenital or infantile onset, as well as others whose symptoms started in the second decade. The patients with early onset developed a spinal muscular atrophy-like picture, whereas in the later onset cases, the initial symptoms were cramps, distal weakness and sensory impairment. Weakness and atrophy progressed in a random and asymmetric fashion and involved limb girdle muscles, leading to a severe incapacity in adulthood. Sensory loss was always prominent and proportional to disease severity. Electrophysiological studies were consistent with an asymmetric axonal motor and sensory neuropathy, while fasciculations and myokymia were recorded rather frequently by needle electromyography. Sural nerve biopsy revealed pronounced multifocal depletion of myelinated fibres with some regenerative clusters and occasional small onion bulbs. Morc2 is expressed in both axons and Schwann cells of mouse peripheral nerve. Different roles in biological processes have been described for MORC2. As the silencing of Charcot-Marie-Tooth disease genes have been associated with DNA damage response, it is tempting to speculate that a deregulation of this pathway may be linked to the axonal degeneration observed in MORC2 neuropathy, thus adding a new pathogenic mechanism to the long list of causes of Charcot-Marie-Tooth disease.

}, keywords = {Adult, Aged, Animals, Axons, Charcot-Marie-Tooth Disease, Female, gene expression, Humans, Infant, Male, Mice, Middle Aged, mutation, Pedigree, Phenotype, Sciatic Nerve, Sural Nerve, Transcription Factors, Young Adult}, issn = {1460-2156}, doi = {10.1093/brain/awv311}, author = {Sevilla, Teresa and Lupo, Vincenzo and Mart{\'\i}nez-Rubio, Dolores and Sancho, Paula and Sivera, Rafael and Chumillas, Mar{\'\i}a J and Garc{\'\i}a-Romero, Mar and Pascual-Pascual, Samuel I and Muelas, Nuria and Dopazo, Joaquin and V{\'\i}lchez, Juan J and Palau, Francesc and Espin{\'o}s, Carmen} } @article {450, title = {Screening of CD96 and ASXL1 in 11 patients with Opitz C or Bohring-Opitz syndromes.}, journal = {Am J Med Genet A}, volume = {170A}, year = {2016}, month = {2016 Jan}, pages = {24-31}, abstract = {

Opitz C trigonocephaly (or Opitz C syndrome, OTCS) and Bohring-Opitz syndrome (BOS or C-like syndrome) are two rare genetic disorders with phenotypic overlap. The genetic causes of these diseases are not understood. However, two genes have been associated with OTCS or BOS with dominantly inherited de novo mutations. Whereas CD96 has been related to OTCS (one case) and to BOS (one case), ASXL1 has been related to BOS only (several cases). In this study we analyze CD96 and ASXL1 in a group of 11 affected individuals, including 2 sibs, 10 of them were diagnosed with OTCS, and one had a BOS phenotype. Exome sequences were available on six patients with OTCS and three parent pairs. Thus, we could analyze the CD96 and ASXL1 sequences in these patients bioinformatically. Sanger sequencing of all exons of CD96 and ASXL1 was carried out in the remaining patients. Detailed scrutiny of the sequences and assessment of variants allowed us to exclude putative pathogenic and private mutations in all but one of the patients. In this patient (with BOS) we identified a de novo mutation in ASXL1 (c.2100dupT). By nature and location within the gene, this mutation resembles those previously described in other BOS patients and we conclude that it may be responsible for the condition. Our results indicate that in 10 of 11, the disease (OTCS or BOS) cannot be explained by small changes in CD96 or ASXL1. However, the cohort is too small to make generalizations about the genetic etiology of these diseases.

}, keywords = {Adolescent, Antigens, CD, Child, Child, Preschool, Craniosynostoses, Exome, Female, High-Throughput Nucleotide Sequencing, Humans, Infant, Intellectual Disability, Male, mutation, Pedigree, Phenotype, Prognosis, Repressor Proteins}, issn = {1552-4833}, doi = {10.1002/ajmg.a.37418}, author = {Urreizti, Roser and Roca-Ayats, Neus and Trepat, Judith and Garcia-Garcia, Francisco and Alem{\'a}n, Alejandro and Orteschi, Daniela and Marangi, Giuseppe and Neri, Giovanni and Opitz, John M and Dopazo, Joaquin and Cormand, Bru and Vilageliu, Llu{\"\i}sa and Balcells, Susana and Grinberg, Daniel} } @article {456, title = {The EGR2 gene is involved in axonal Charcot-Marie-Tooth disease.}, journal = {Eur J Neurol}, volume = {22}, year = {2015}, month = {2015 Dec}, pages = {1548-55}, abstract = {

BACKGROUND AND PURPOSE: A three-generation family affected by axonal Charcot-Marie-Tooth disease (CMT) was investigated with the aim of discovering genetic defects and to further characterize the phenotype.

METHODS: The clinical, nerve conduction studies and muscle magnetic resonance images of the patients were reviewed. A whole exome sequencing was performed and the changes were investigated by genetic studies, in silico analysis and luciferase reporter assays.

RESULTS: A novel c.1226G>A change (p.R409Q) in the EGR2 gene was identified. Patients presented with a typical, late-onset axonal CMT phenotype with variable severity that was confirmed in the ancillary tests. The in silico studies showed that the residue R409 is an evolutionary conserved amino acid. The p.R409Q mutation, which is predicted as probably damaging, would alter the conformation of the protein slightly and would cause a decrease of gene expression.

CONCLUSIONS: This is the first report of an EGR2 mutation presenting as an axonal CMT phenotype with variable severity. This study broadens the phenotype of the EGR2-related neuropathies and suggests that the genetic testing of patients suffering from axonal CMT should include the EGR2 gene.

}, keywords = {Adult, Aged, Aged, 80 and over, Axons, Charcot-Marie-Tooth Disease, Early Growth Response Protein 2, Exome, Female, Humans, Male, Middle Aged, mutation, Pedigree, Phenotype, Severity of Illness Index, Young Adult}, issn = {1468-1331}, doi = {10.1111/ene.12782}, author = {Sevilla, T and Sivera, R and Mart{\'\i}nez-Rubio, D and Lupo, V and Chumillas, M J and Calpena, E and Dopazo, J and V{\'\i}lchez, J J and Palau, F and Espin{\'o}s, C} } @article {467, title = {Re-evaluation casts doubt on the pathogenicity of homozygous USH2A p.C759F.}, journal = {Am J Med Genet A}, volume = {167}, year = {2015}, month = {2015 Jul}, pages = {1597-600}, abstract = {

Mutations in USH2A are a common cause of Retinitis Pigmentosa (RP). Among the most frequently reported USH2A variants, c.2276G>T (p.C759F) has been found in both affected and healthy individuals. The pathogenicity of this variant remains controversial since it was detected in homozygosity in two healthy siblings of a Spanish family (S23), eleven years ago. The fact that these individuals remain asymptomatic today, prompted us to study the presence of other pathogenic variants in this family using targeted resequencing of 26 retinal genes in one of the affected individuals. This approach allowed us to identify one novel pathogenic homozygous mutation in exon 13 of PDE6B (c.1678C>T; p.R560C). This variant cosegregated with the disease and was absent in 200 control individuals. Remarkably, the identified variant in PDE6B corresponds to the mutation responsible of the retinal degeneration in the naturally occurring rd10 mutant mice. To our knowledge, this is the first report of the identification of the rd10 mice mutation in a RP family. These findings, together with a review of the literature, support the hypothesis that homozygous p.C759F mutations are not pathogenic and led us to exclude the implication of p.C759F in the RP of family S23. Our results indicate the need of re-evaluating all families genetically diagnosed with this mutation.

}, keywords = {Base Sequence, Cyclic Nucleotide Phosphodiesterases, Type 6, Extracellular Matrix Proteins, Gene Library, Humans, Molecular Sequence Data, Mutation, Missense, Pedigree, Retinitis pigmentosa, Sequence Analysis, DNA, Spain}, issn = {1552-4833}, doi = {10.1002/ajmg.a.37003}, author = {Pozo, Mar{\'\i}a Gonz{\'a}lez-Del and Bravo-Gil, Nereida and M{\'e}ndez-Vidal, Cristina and Montero-de-Espinosa, Ignacio and Mill{\'a}n, Jos{\'e} M and Dopazo, Joaquin and Borrego, Salud and Anti{\v n}olo, Guillermo} } @article {463, title = {Whole-exome sequencing reveals ZNF408 as a new gene associated with autosomal recessive retinitis pigmentosa with vitreal alterations.}, journal = {Hum Mol Genet}, volume = {24}, year = {2015}, month = {2015 Jul 15}, pages = {4037-48}, abstract = {

Retinitis pigmentosa (RP) is a group of progressive inherited retinal dystrophies that cause visual impairment as a result of photoreceptor cell death. RP is heterogeneous, both clinically and genetically making difficult to establish precise genotype-phenotype correlations. In a Spanish family with autosomal recessive RP (arRP), homozygosity mapping and whole-exome sequencing led to the identification of a homozygous mutation (c.358_359delGT; p.Ala122Leufs*2) in the ZNF408 gene. A screening performed in 217 additional unrelated families revealed another homozygous mutation (c.1621C>T; p.Arg541Cys) in an isolated RP case. ZNF408 encodes a transcription factor that harbors 10 predicted C2H2-type fingers thought to be implicated in DNA binding. To elucidate the ZNF408 role in the retina and the pathogenesis of these mutations we have performed different functional studies. By immunohistochemical analysis in healthy human retina, we identified that ZNF408 is expressed in both cone and rod photoreceptors, in a specific type of amacrine and ganglion cells, and in retinal blood vessels. ZNF408 revealed a cytoplasmic localization and a nuclear distribution in areas corresponding with the euchromatin fraction. Immunolocalization studies showed a partial mislocalization of the p.Arg541Cys mutant protein retaining part of the WT protein in the cytoplasm. Our study demonstrates that ZNF408, previously associated with Familial Exudative Vitreoretinopathy (FEVR), is a new gene causing arRP with vitreous condensations supporting the evidence that this protein plays additional functions into the human retina.

}, keywords = {Amino Acid Sequence, Animals, Chlorocebus aethiops, Chromosome Mapping, COS Cells, DNA-Binding Proteins, Exome, Genome-Wide Association Study, High-Throughput Nucleotide Sequencing, Homozygote, Humans, Molecular Sequence Data, Mutant Proteins, Pedigree, Retina, Retinal Cone Photoreceptor Cells, Retinal Rod Photoreceptor Cells, Retinitis pigmentosa, Transcription Factors}, issn = {1460-2083}, doi = {10.1093/hmg/ddv140}, author = {Avila-Fernandez, Almudena and Perez-Carro, Raquel and Corton, Marta and Lopez-Molina, Maria Isabel and Campello, Laura and Garanto, Alejandro and Fernandez-Sanchez, Laura and Duijkers, Lonneke and Lopez-Martinez, Miguel Angel and Riveiro-Alvarez, Rosa and da Silva, Luciana Rodrigues Jacy and Sanchez-Alcudia, Roc{\'\i}o and Martin-Garrido, Esther and Reyes, Noelia and Garcia-Garcia, Francisco and Dopazo, Joaquin and Garcia-Sandoval, Blanca and Collin, Rob W J and Cuenca, Nicolas and Ayuso, Carmen} } @article {489, title = {Exome sequencing reveals novel and recurrent mutations with clinical significance in inherited retinal dystrophies.}, journal = {PLoS One}, volume = {9}, year = {2014}, month = {2014}, pages = {e116176}, abstract = {

This study aimed to identify the underlying molecular genetic cause in four Spanish families clinically diagnosed of Retinitis Pigmentosa (RP), comprising one autosomal dominant RP (adRP), two autosomal recessive RP (arRP) and one with two possible modes of inheritance: arRP or X-Linked RP (XLRP). We performed whole exome sequencing (WES) using NimbleGen SeqCap EZ Exome V3 sample preparation kit and SOLID 5500xl platform. All variants passing filter criteria were validated by Sanger sequencing to confirm familial segregation and the absence in local control population. This strategy allowed the detection of: (i) one novel heterozygous splice-site deletion in RHO, c.937-2_944del, (ii) one rare homozygous mutation in C2orf71, c.1795T>C; p.Cys599Arg, not previously associated with the disease, (iii) two heterozygous null mutations in ABCA4, c.2041C>T; p.R681* and c.6088C>T; p.R2030*, and (iv) one mutation, c.2405-2406delAG; p.Glu802Glyfs*31 in the ORF15 of RPGR. The molecular findings for RHO and C2orf71 confirmed the initial diagnosis of adRP and arRP, respectively, while patients with the two ABCA4 mutations, both previously associated with Stargardt disease, presented symptoms of RP with early macular involvement. Finally, the X-Linked inheritance was confirmed for the family with the RPGR mutation. This latter finding allowed the inclusion of carrier sisters in our preimplantational genetic diagnosis program.

}, keywords = {Adolescent, Adult, Amino Acid Sequence, Base Sequence, Child, Chromosome Segregation, DNA Mutational Analysis, Exome, Family, Female, Humans, Inheritance Patterns, Male, Middle Aged, Molecular Sequence Data, mutation, Pedigree, Retinal Dystrophies, Rhodopsin}, issn = {1932-6203}, doi = {10.1371/journal.pone.0116176}, author = {Gonz{\'a}lez-del Pozo, Mar{\'\i}a and M{\'e}ndez-Vidal, Cristina and Bravo-Gil, Nereida and Vela-Boza, Alicia and Dopazo, Joaquin and Borrego, Salud and Anti{\v n}olo, Guillermo} } @article {490, title = {Novel RP1 mutations and a recurrent BBS1 variant explain the co-existence of two distinct retinal phenotypes in the same pedigree.}, journal = {BMC Genet}, volume = {15}, year = {2014}, month = {2014 Dec 14}, pages = {143}, abstract = {

BACKGROUND: Molecular diagnosis of Inherited Retinal Dystrophies (IRD) has long been challenging due to the extensive clinical and genetic heterogeneity present in this group of disorders. Here, we describe the clinical application of an integrated next-generation sequencing approach to determine the underlying genetic defects in a Spanish family with a provisional clinical diagnosis of autosomal recessive Retinitis Pigmentosa (arRP).

RESULTS: Exome sequencing of the index patient resulted in the identification of the homozygous BBS1 p.M390R mutation. Sanger sequencing of additional members of the family showed lack of co-segregation of the p.M390R variant in some individuals. Clinical reanalysis indicated co-ocurrence of two different phenotypes in the same family: Bardet-Biedl syndrome in the individual harboring the BBS1 mutation and non-syndromic arRP in extended family members. To identify possible causative mutations underlying arRP, we conducted disease-targeted gene sequencing using a panel of 26 IRD genes. The in-house custom panel was validated using 18 DNA samples known to harbor mutations in relevant genes. All variants were redetected, indicating a high mutation detection rate. This approach allowed the identification of two novel heterozygous null mutations in RP1 (c.4582_4585delATCA; p.I1528Vfs*10 and c.5962dupA; p.I1988Nfs*3) which co-segregated with the disease in arRP patients. Additionally, a mutational screening in 96 patients of our cohort with genetically unresolved IRD revealed the presence of the c.5962dupA mutation in one unrelated family.

CONCLUSIONS: The combination of molecular findings for RP1 and BBS1 genes through exome and gene panel sequencing enabled us to explain the co-existence of two different retinal phenotypes in a family. The identification of two novel variants in RP1 suggests that the use of panels containing the prevalent genes of a particular population, together with an optimized data analysis pipeline, is an efficient and cost-effective approach that can be reliably implemented into the routine diagnostic process of diverse inherited retinal disorders. Moreover, the identification of these novel variants in two unrelated families supports the relatively high prevalence of RP1 mutations in Spanish population and the role of private mutations for commonly mutated genes, while extending the mutational spectrum of RP1.

}, keywords = {Bardet-Biedl Syndrome, Base Sequence, Case-Control Studies, DNA Mutational Analysis, Eye Proteins, Genes, Recessive, Genetic Association Studies, Humans, Microsatellite Repeats, Microtubule-Associated Proteins, Mutation, Missense, Pedigree, Phenotype, Retina, Retinitis pigmentosa}, issn = {1471-2156}, doi = {10.1186/s12863-014-0143-2}, author = {M{\'e}ndez-Vidal, Cristina and Bravo-Gil, Nereida and Gonz{\'a}lez-del Pozo, Mar{\'\i}a and Vela-Boza, Alicia and Dopazo, Joaquin and Borrego, Salud and Anti{\v n}olo, Guillermo} } @article {575, title = {Mutation spectrum of EYS in Spanish patients with autosomal recessive retinitis pigmentosa.}, journal = {Hum Mutat}, volume = {31}, year = {2010}, month = {2010 Nov}, pages = {E1772-800}, abstract = {

Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. We have recently identified a new gene(EYS) encoding an ortholog of Drosophila space maker (spam) as a commonly mutated gene in autosomal recessive RP. In the present study, we report the identification of 73 sequence variations in EYS, of which 28 are novel. Of these, 42.9\% (12/28) are very likely pathogenic, 17.9\% (5/28)are possibly pathogenic, whereas 39.3\% (11/28) are SNPs. In addition, we have detected 3 pathogenic changes previously reported in other populations. We are also presenting the characterisation of EYS homologues in different species, and a detailed analysis of the EYS domains, with the identification of an interesting novel feature: a putative coiled-coil domain.Majority of the mutations in the arRP patients have been found within the domain structures of EYS. The minimum observed prevalence of distinct EYS mutations in our group of patients is of 15.9\% (15/94), confirming a major involvement of EYS in the pathogenesis of arRP in the Spanish population. Along with the detection of three recurrent mutations in Caucasian population, our hypothesis of EYS being the first prevalent gene in arRP has been reinforced in the present study.

}, keywords = {Amino Acid Sequence, Animals, Case-Control Studies, DNA Mutational Analysis, Drosophila Proteins, Evolution, Molecular, Eye Proteins, Female, Genes, Recessive, Genetic Variation, Humans, Male, Molecular Sequence Data, mutation, Pedigree, Polymorphism, Single Nucleotide, Protein Structure, Tertiary, Retinitis pigmentosa, Spain, Structural Homology, Protein}, issn = {1098-1004}, doi = {10.1002/humu.21334}, author = {Barrag{\'a}n, Isabel and Borrego, Salud and Pieras, Juan Ignacio and Gonz{\'a}lez-del Pozo, Mar{\'\i}a and Santoyo, Javier and Ayuso, Carmen and Baiget, Montserrat and Mill{\'a}n, Jos{\'e} M and Mena, Marcela and Abd El-Aziz, Mai M and Audo, Isabelle and Zeitz, Christina and Littink, Karin W and Dopazo, Joaquin and Bhattacharya, Shomi S and Anti{\v n}olo, Guillermo} }