C syndrome - what do we know and what could the future hold?

In 1969 Opitz et al. described two siblings with a new syndrome, which they called ‘C syndrome of multiple congenital abnormalities’ and was presented as a ‘probably private syndrome’. After this first description, new cases appeared with highly similar phenotypes and a new syndrome, known as C Syndrome, Opitz C Syndrome or Opitz Trigonocephaly Syndrome (OCS; MIM # 211,750) was firmly established

A CBS haplotype and a polymorphism at the MSR gene are associated with cardiovascular disease in a Spanish case–control study

Objectives: The aim of this study was to evaluate the association of polymorphisms present in genes related to homocysteine (Hcy) metabolism with coronary artery disease (CAD). Design and methods: We examined 8 polymorphisms in the cystathionine β-synthase (CBS), glutamate carboxypeptidase II (GCPII), methionine synthase (MS), methionine synthase reductase (MSR) and methylenetetrahydrofolate reductase (MTHFR) genes in 140 CAD patients and 113 controls, by means of Chi-square, logistic regression, ANOVA and the Mann–Whitney U test. Results: The c.66 G allele of MSR conferred an odds-ratio for CAD of 1.76 (95% CI 1.12–2.77), while a CBS haplotype [c.699C–c.844wt– c.1080C] was found over-represented in CAD [OR of 2.16 (1.29–3.63)]. Conclusions: Our results not only highlight the involvement of the MSR and CBS genes in the etiology of cardiovascular disease, but also emphasize the strength of haplotype analyses in association studies.Fil: Urreizti, Roser. Universidad de Barcelona; EspañaFil: Asteggiano, Carla Gabriela. Universidad de Barcelona; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Vilaseca, Maria Antonia. Hospital Sant Joan de Deu Barcelona; EspañaFil: Corbella, Emili. Hospital de Bellvitge; EspañaFil: Pintó, Xavier. Hospital de Bellvitge; EspañaFil: Grinberg, Daniel. Universidad de Barcelona; EspañaFil: Balcells, Susana. Universidad de Barcelona; Españ

The ASXL1 mutation p.Gly646Trpfs*12 found in a Turkish boy with Bohring-Opitz syndrome

Bohring‐Opitz syndrome (BOS, MIM #605039) is a rare and severe disease characterized mainly by intrauterine growth retardation, feeding difficulties, severe to profound developmental delay, nonspecific brain abnormalities, microcephaly, flexion at the elbows with ulnar deviation and flexion of the wrists and metacarpophalangeal joints (known as BOS posture) and distinctive facial features.1 Heterozygous ASXL1 truncating mutations have been identified as the main cause of BOS.1, 2 A recent publication 3 called the attention to the fact that mutations associated with BOS are also present in the ExAC (Exome Aggregation Consortium) database.4 As ASXL1 is one of the genes most commonly mutated during hematopoietic clonal expansion of cells, the authors hypothesized that the presence of this mutation in public databases could be due to somatic mosaicism, and they could confirm the hypothesis by manual examination of the ExAC WES reads

Identification and functional analyses of CBS alleles in Spanish and Argentinian homocystinuric patients

Homocystinuria due to CBS deficiency is a rare autosomal recessive disorder characterized by elevated plasma levels of homocysteine (Hcy) and methionine (Met). Here we present the analysis of 22 unrelated patients of different geographical origins, mainly Spanish and Argentinian. Twenty-two different mutations were found, 10 of which were novel. Five new mutations were missense and five were deletions of different sizes, including a 794-bp deletion (c.532-37-736 + 438del794) detected by Southern blot analysis. To assess the pathogenicity of these mutations, seven were expressed heterologously in Escherichia coli and their enzyme activities were assayed in vitro, in the absence and presence of the CBS activators PLP and SAM. The presence of the mutant proteins was confirmed by Western blotting. Mutations p.M173del, p.I278S, p.D281N, and p.D321V showed null activity in all conditions tested, whereas mutations p.49L, p.P200L and p.A446S retained different degrees of activity and response to stimulation. Finally, a minigene strategy allowed us to demonstrate the pathogenicity of an 8-bp intronic deletion, which led to the skipping of exon 6. In general, frameshifting deletions correlated with a more severe phenotype, consistent with the concept that missense mutations may recover enzymatic activity under certain conditions. © 2011 Wiley-Liss, Inc.Fil: Cozar, Mónica. Universidad de Barcelona; EspañaFil: Urreizti, Roser. Universidad de Barcelona; EspañaFil: Vilarinho, Laura. Instituto de Genética Médica Jacinto Magalhaes; PortugalFil: Grosso, Carola. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Estudios de las Metabolopatías Congénitas; ArgentinaFil: Dodelson de Kremer, Raquel. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Estudios de las Metabolopatías Congénitas; ArgentinaFil: Asteggiano, Carla Gabriela. Gobierno de la Provincia de Córdoba. Ministerio de Salud. Hospital de Niños de la Santísima Trinidad; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dalmau, Jaime. Hospital Infantil La Fe; EspañaFil: García, Ana María. Hospital Infantil La Fe; EspañaFil: Vilaseca, María Antonia. Hospital Sant Joan de De ́u; EspañaFil: Grinberg Vaisman, Daniel Raúl. Universidad de Barcelona; EspañaFil: Balcells, Susana. Universidad de Barcelona; Españ

Identification and functional analyses of CBS alleles in Spanish and Argentinian homocystinuric patients

Homocystinuria due to CBS deficiency is a rare autosomal recessive disorder characterized by elevated plasma levels of homocysteine (Hcy) and methionine (Met). Here we present the analysis of 22 unrelated patients of different geographical origins, mainly Spanish and Argentinian. Twenty‐two different mutations were found, 10 of which were novel. Five new mutations were missense and five were deletions of different sizes, including a 794‐bp deletion (c.532−37_736 + 438del794) detected by Southern blot analysis. To assess the pathogenicity of these mutations, seven were expressed heterologously in Escherichia coli and their enzyme activities were assayed in vitro, in the absence and presence of the CBS activators PLP and SAM. The presence of the mutant proteins was confirmed by Western blotting. Mutations p.M173del, p.I278S, p.D281N, and p.D321V showed null activity in all conditions tested, whereas mutations p.49L, p.P200L and p.A446S retained different degrees of activity and response to stimulation. Finally, a minigene strategy allowed us to demonstrate the pathogenicity of an 8‐bp intronic deletion, which led to the skipping of exon 6. In general, frameshifting deletions correlated with a more severe phenotype, consistent with the concept that missense mutations may recover enzymatic activity under certain conditions

MiRNA profiling of whole trabecular bone: identification of osteoporosis-related changes in MiRNAs in human hip bones

Background MicroRNAs (miRNAs) are important regulators of gene expression, with documented roles in bone metabolism and osteoporosis, suggesting potential therapeutic targets. Our aim was to identify miRNAs differentially expressed in fractured vs nonfractured bones. Additionally, we performed a miRNA profiling of primary osteoblasts to assess the origin of these differentially expressed miRNAs. Methods Total RNA was extracted from (a) fresh femoral neck trabecular bone from women undergoing hip replacement due to either osteoporotic fracture (OP group, n = 6) or osteoarthritis in the absence of osteoporosis (Control group, n = 6), matching the two groups by age and body mass index, and (b) primary osteoblasts obtained from knee replacement due to osteoarthritis (n = 4). Samples were hybridized to a microRNA array containing more than 1900 miRNAs. Principal component analysis (PCA) plots and heat map hierarchical clustering were performed. For comparison of expression levels, the threshold was set at log fold change > 1.5 and a p-value < 0.05 (corrected for multiple testing). Results Both PCA and heat map analyses showed that the samples clustered according to the presence or absence of fracture. Overall, 790 and 315 different miRNAs were detected in fresh bone samples and in primary osteoblasts, respectively, 293 of which were common to both groups. A subset of 82 miRNAs was differentially expressed (p < 0.05) between osteoporotic and control osteoarthritic samples. The eight miRNAs with the lowest p-values (and for which a validated miRNA qPCR assay was available) were assayed, and two were confirmed: miR-320a and miR-483-5p. Both were over-expressed in the osteoporotic samples and expressed in primary osteoblasts. miR-320a is known to target CTNNB1 and predicted to regulate RUNX2 and LEPR, while miR-483-5p down-regulates IGF2. We observed a reduction trend for this target gene in the osteoporotic bone. Conclusions We identified two osteoblast miRNAs over-expressed in osteoporotic fractures, which opens novel prospects for research and therapy

De Novo PORCN and ZIC2 mutations in a highly consanguineous family

We present a Turkish family with two cousins (OC15 and OC15b) affected with syndromic developmental delay, microcephaly, and trigonocephaly but with some phenotypic traits distinct between them. OC15 showed asymmetrical skeletal defects and syndactyly, while OC15b presented with a more severe microcephaly and semilobal holoprosencephaly. All four progenitors were related and OC15 parents were consanguineous. Whole Exome Sequencing (WES) analysis was performed on patient OC15 as a singleton and on the OC15b trio. Selected variants were validated by Sanger sequencing. We did not identify any shared variant that could be associated with the disease. Instead, each patient presented a de novo heterozygous variant in a different gene. OC15 carried a nonsense mutation (p.Arg95*) in PORCN, which is a gene responsible for Goltz-Gorlin syndrome, while OC15b carried an indel mutation in ZIC2 leading to the substitution of three residues by a proline (p.His404_Ser406delinsPro). Autosomal dominant mutations in ZIC2 have been associated with holoprosencephaly 5. Both variants are absent in the general population and are predicted to be pathogenic. These two de novo heterozygous variants identified in the two patients seem to explain the major phenotypic alterations of each particular case, instead of a homozygous variant that would be expected by the underlying consanguinity

A broad spectrum of genomic changes in Latinamerican patients with EXT1/EXT2-CDG

Multiple osteochondromatosis (MO), or EXT1/EXT2-CDG, is an autosomal dominant O-linked glycosylation disorder characterized by the formation of multiple cartilage-capped tumors (osteochondromas). In contrast, solitary osteochondroma (SO) is a non-hereditary condition. EXT1 and EXT2, are tumor suppressor genes that encode glycosyltransferases involved in heparan sulfate elongation. We present the clinical and molecular analysis of 33 unrelated Latin American patients (27 MO and 6 SO). Sixty-three percent of all MO cases presented severe phenotype and two malignant transformations to chondrosarcoma (7%). We found the mutant allele in 78% of MO patients. Ten mutations were novel. The disease-causing mutations remained unknown in 22% of the MO patients and in all SO patients. No second mutational hit was detected in the DNA of the secondary chondrosarcoma from a patient who carried a nonsense EXT1 mutation. Neither EXT1 nor EXT2 protein could be detected in this sample. This is the first Latin American research program on EXT1/EXT2-CDG

The p.T191M mutation of the CBS gene is highly prevalent among homocystinuric patients from Spain, Portugal and South America

Classical homocystinuria is due to cystathionine beta-synthase (CBS) deficiency. More than 130 mutations, which differ in prevalence and severity, have been described at the CBS gene. Mutation p.I278T is very prevalent, has been found in all European countries where it has been looked for with the exception of the Iberian peninsula, and is known to respond to vitamin B-6. On the other hand, mutation p.T191M is prevalent in Spain and Portugal and does not respond to B-6. We analysed 30 pedigrees from Spain, Portugal, Colombia and Argentina, segregating for homocystinuria. the p.T191M mutation was detected in patients from all four countries and was particularly prevalent in Colombia. the number of p.T191M alleles described in this Study, together with those previously published, is 71. the prevalence of p.T191M among CBS mutant alleles in the different countries was: 0.75 in Colombia, 0.52 in Spain, 0.33 in Portugal, 0.25 in Venezuela, 0.20 in Argentina and 0.14 in Brazil. Haplotype analyses suggested a double origin for this mutation. No genotype-phenotype correlation other than the B-6-nonresponsiveness Could be established for the p.T191M mutation. Additionally,. three new mutations, p.M173V, p.I429del and c.69_70+8de110, were found. the p.M173V was associated with a mild, B-6-responsive, phenotype.Univ Barcelona, Fac Biol, Dept Genet, E-08028 Barcelona, SpainUniv Nacl Cordoba, Ctr Estud Metab Congenitas, Hosp Ninos, Cordoba, ArgentinaPontificia Univ Javeriana, Inst Genet Humana, Bogota, ColombiaUniv Antioquia, Fac Med, Depto Fisiol & Bioquim, Medellin, ColombiaFundac Estud Enfermedades Neurometab, Buenos Aires, DF, ArgentinaInst Genet Med Jacinto Magalhaes, Oporto, PortugalUniversidade Federal de São Paulo, UNIFESP, EPM, Dept Pediat, São Paulo, BrazilHosp Ramon y Cajal, Serv Pediat, Unidad Enfermedades Metab, Madrid, SpainHosp Univ Materno Infantil, Unidad Gastroenterol & Nutr, Las Palmas Gran Canaria, SpainHosp Infantil Le Fe, Unidad Nutr & Metab, Valencia, SpainHosp Clin Univ Santiago, Dept Pediat, Santiago de Compostela, SpainCorp Sanitaria Clin, Inst Bioquim Clin, Barcelona, SpainHosp St Joan Deu, Serv Bioquim, Barcelona, SpainUniversidade Federal de São Paulo, UNIFESP, EPM, Dept Pediat, São Paulo, BrazilWeb of Scienc

Mutations in the EXT1 and EXT2 genes in Spanish patients with multiple osteochondromas

Multiple osteochondromas is an autosomal dominant skeletal disorder characterized by the formation of multiple cartilage-capped tumours. Two causal genes have been identified, EXT1 and EXT2, which account for 65% and 30% of cases, respectively. We have undertaken a mutation analysis of the EXT1 and EXT2 genes in 39 unrelated Spanish patients, most of them with moderate phenotype, and looked for genotype-phenotype correlations. We found the mutant allele in 37 patients, 29 in EXT1 and 8 in EXT2. Five of the EXT1 mutations were deletions identified by MLPA. Two cases of mosaicism were documented. We detected a lower number of exostoses in patients with missense mutation versus other kinds of mutations. In conclusion, we found a mutation in EXT1 or in EXT2 in 95% of the Spanish patients. Eighteen of the mutations were novel