Ala397Asp Mutation of Myosin VIIA Segregating in a Spanish Family with Usher Syndrome Type Ib

[EN] In the current study, 12 Spanish families affected by type-I Usher syndrome, that was previously linked to chromosome 11q, were screened for the presence of mutations in the N-terminal coding portion of the motor domain of the myosin VIIA gene by single-strand conformation polymorphism analysis of the first 14 exons. A mutation (Ala397Asp) segregating with the disease was identified, and several polymorphisms were also detected. It is presumed that the other USH1B mutations in these families could be located in the unscreened regions of the gene.The authors would like to thank the Fondo de Investigaciones Sanitarias (FISS n0 95/1814), the ONCE and the Fundación ONCE for financial support. We acknowledge patients and their family members, as well as the Asociación de retinosis pigmentaria de la Comunidad Valenciana and the FAARPEE, for their help and cooperation.Espinós-Armero, CÁ.; Millán, JM.; Sánchez, F.; Beneyto, M.; Nájera, C. (1998). Ala397Asp Mutation of Myosin VIIA Segregating in a Spanish Family with Usher Syndrome Type Ib. Human Genetics. 102(6):691-694. https://doi.org/10.1007/s004390050763691694102

Association of the 3467C>T mutation (T1156M) in the von Willebrands factor gene with dominant type 1 von Willebrands disease

[EN] Type I is the most frequent form of von Willebrand's disease, which is characterized by a quantitative partial deficiency of von Willebrand's factor. At present, only two mutations located in the D3 domain (C1149R, C1130F) have been reported to cause the classic type I variant. The 3467C>T transition that predicts the T1156M amino acid change was detected in seven patients from one family and was not found in 110 normal alleles screened. This is a candidate mutation to cause dominant type I variant with complete penetrance. On the other hand, neither of the two mutations mentioned above has been detected in the other 15 families studied with type I or possible type 1 patients.This work was supported in part by grant #99/0633 (FIS, Spain). We wish to thank R. Curats and J.M. Montoro for their technical assistance and Mr. Peter Blair for his linguistic advice.Casaña-Gargallo, MP.; Francisco Martínez; Saturnino Haya; Espinós-Armero, CÁ.; José Antonio Aznar (2001). Association of the 3467C>T mutation (T1156M) in the von Willebrands factor gene with dominant type 1 von Willebrands disease. Annals of Hematology. 80(7):381-383. https://doi.org/10.1007/s00277010030738138380

Significant linkage and non-linkage of type 1 von Willebrand Disease to the von Willebrand factor gene

[EN] Significant linkage of types 2A and 2B von Willebrand disease (VWD) to the von Willebrand factor (VWF) gene have been reported, as well as mutations in the VWF gene. However, data for the partial quantitative variant are less consistent. An inconsistency of association between the type 1 VWD phenotype and genotype has been reported recently. We undertook linkage analysis of 12 families with definite or possible type 1 VWD patients. One family with classic type 1 VWD had a high lod score (Z = 5.28, theta = 0.00). A total lod score of 10.68 was obtained for the four families with fully penetrant disease. In two families linkage was rejected, while three families did not show conclusive evidence of linkage. This study corroborates ABO blood group influence, especially in patients with mild deficiencies and/or incomplete penetrance, Indirect genetic analysis may be an option for diagnosing asymptomatic or presymptomatic type 1 VWD carriers, particularly in families showing higher penetrance. The study indicates defects of the VWF locus are to be expected in more than half of the families studied. However, as defects at different loci may be the cause of this phenotype, the results of the segregation analyses should be interpreted with caution, especially in studies involving small families, or mild expressions of the disorder or incomplete penetrance.This work was partly supported by F1S grant # 99/0633 (Spain). We wish to thank J. M. Montoro for the multimeric structure analyses, R. Curats for his help in the segregation analyses, all the staff of the `Unidad de CoagulopatõÂas CongeÂnitas de la Comunidad 5alenciana' for their technical and clinical assistance, and Mr Peter Blair for the linguistic advice given in writing this paper.Casaña-Gargallo, MP.; Martínez, F.; Haya, S.; Espinós-Armero, CÁ.; Aznar, JA. (2001). Significant linkage and non-linkage of type 1 von Willebrand Disease to the von Willebrand factor gene. British Journal of Haematology. 115(3):692-700. https://doi.org/10.1046/j.1365-2141.2001.03132.x692700115

Genetic analyses of celiac disease in a Spanish population confirm association with CELIAC3 but not with CELIAC4

[EN] Genetic predisposition to celiac disease (CD) is determined primarily by the human leukocyte antigen (HLA) genes (CELIAC1 region; 6p21), although many loci are involved in disease susceptibility. First, we have analysed a large series of CD patients from the Spanish Mediterranean region who had previously been characterised for the HLA complex. We have investigated how relevant regions contribute to CD susceptibility: CELIAC3 (CD28/CTLA4/ICOS region on 2q33) and CELIAC4 (19p13) as well as the tumour necrosis factor alpha (TNF-alpha) and the linfotoxin loci by case-control and association analyses. We highlight the association with the +49*A allele of cytotoxic T-lymphocyte-associated antigen 4 locus (P = 0.01), and the -308*A of TNF-alpha locus (P = 0.0008) in DQ2 individuals, although an independent role for TNF-alpha as risk factor has not been proven. Moreover, we do not confirm the association with the CELIAC4 region polymorphisms described in other populations.We are grateful for the kind collaboration of patients and families and Asociación de Celíacos de la Comunidad Valenciana (ACECOVA). This work was supported by the Fondo de Investigacio¿n Sanitaria (grant PI02573) and by the CSIC Intramural Frontiers Project (PROFICEL). ED holds a fellowship from the Fundacio¿n La Fe. English text revised by F. BarracloughCapilla, A.; Donat, E.; Planelles, D.; Espinós-Armero, CÁ.; Ribes-Koninckx, C.; Palau, F. (2007). Genetic analyses of celiac disease in a Spanish population confirm association with CELIAC3 but not with CELIAC4. Tissue Antigens. 70(4):324-329. https://doi.org/10.1111/j.1399-0039.2007.00899.x32432970

Search for Mutations in a Segment of the Exon 28 of the Human Von Willebrand Factor Gene. New Mutations, R1315C and R1341W, Associated with Type 2M and 2B Variants

[EN] von Willebrand Disease (vWD) is the most frequently inherited bleeding disorder in humans, and is caused by a qualitative and/or quantitative abnormality of the von Willebrand factor (vWF), A large number of defects that cause qualitative variants have been located in the Al domain of the vWF, which contains sites for interaction with platelet glycoprotein Ib (GPIb). We have developed a new approach to detect mutations based on Ddel digestion and single-strand conformation polymorphism analysis. A segment of 487 nucleotides, extending from intron 27 to codon 1368 of the pre-pro vWF was amplified from genomic DNA, The cleavage with Ddel yields two fragments of appropriate size for this kind of analysis and confirms that the gene, rather than the pseudogene, is being investigated, Six families with type 2B vWD: one type 2M vWD family, and one another type 2A vWD family were studied. After sequencing the fragments with an altered electrophoretic pattern, we found four mutations previously described-R1308C, V1316M, P1337L, and R1306W-in patients with 2B vWD, The last one arose de novo in the patient. In addition, two new candidate mutations were observed: R1315C and R1341W. The first one was associated to type 2M vWD, whereas the one second cosegregated with type 2B vWD. The fact that these new mutations were not found in 100 normal alleles screened further supports their causal relationship with the disease, These mutations, which induce either a gain or a loss of function, further show an important regulatory role of this region in the binding of vWF to GPIb and its implications in causing disease.We wish to thank J.M. Montoro for performing multimeric assays and R. Curats for his technical assistance.Casaña, P.; Martínez, F.; Espinós-Armero, CÁ.; Haya, S.; Lorenzo, JI.; Aznar, JA. (1998). Search for Mutations in a Segment of the Exon 28 of the Human Von Willebrand Factor Gene. New Mutations, R1315C and R1341W, Associated with Type 2M and 2B Variants. American Journal of Hematology. 59(1):57-63. https://doi.org/10.1002/(sici)1096-8652(199809)59:13.0.co;2-z576359

Q1311X: a novel nonsense mutation of putative ancient origin in the von Willebrand factor gene

[EN] Type 3 von Willebrand disease, a recessive autosomally inherited bleeding disorder, refers to complete deficiency of von Willebrand factor (VWF). The novel Q1311X mutation was detected in the homozygous state in four Spanish patients from two apparently unrelated families of gypsy origin. The lack of specific amplification of platelet VWF cDNA from two of the patients indicates reduced levels of mutated gene expression. The similar haplotype linked to mutated alleles suggests a common origin. On the basis of the two instabilities observed and the estimated mutation rate of the microsatellites of intron 40 of the VWF gene, we can estimate that this mutation could have arisen about 2300 years ago.We wish to thank J.M. Montoro and R. Curats for their technical assistance. This work was supported in part by F1S 99/0633.Casaña, P.; Martínez, F.; Haya, S.; Lorenzo, JI.; Espinós-Armero, CÁ.; Aznar, JA. (2000). Q1311X: a novel nonsense mutation of putative ancient origin in the von Willebrand factor gene. British Journal of Haematology. 111(2):552-555. https://doi.org/10.1046/j.1365-2141.2000.02410.x552555111

Missense mutations in the SH3TC2 protein causing Charcot-Marie-Tooth disease type 4C affect its localization in the plasma membrane and endocytic pathway

[EN] Mutations in SH3TC2 (KIAA1985) cause Charcot-Marie-Tooth disease (CMT) type 4C, a demyelinating inherited neuropathy characterized by early-onset and scoliosis. Here we demonstrate that the SH3TC2 protein is present in several components of the endocytic pathway including early endosomes, late endosomes and clathrin-coated vesicles close to the trans-Golgi network and in the plasma membrane. Myristoylation of SH3TC2 in glycine 2 is necessary but not sufficient for the proper location of the protein in the cell membranes. In addition to myristoylation, correct anchoring also needs the presence of SH3 and TPR domains. Mutations that cause a stop codon and produce premature truncations that remove most of the TPR domains are expressed as the wild-type protein. In contrast, missense mutations in or around the region of the first-TPR domain are absent from early endosomes, reduced in plasma membrane and late endosomes and are variably present in clathrin-coated vesicles. Our findings suggest that the endocytic and membrane trafficking pathway is involved in the pathogenesis of CMT4C disease. We postulate that missense mutations of SH3TC2 could impair communication between the Schwann cell and the axon causing an abnormal myelin formation.This work was supported by the Fondo de Investigacion Sanitaria [grant numbers PI08/90857, PI08/0889, CP08/00053] and the Spanish Ministry Science and Innovation [grant number SAF2006-01047]. V. L. is a recipient of JAE predoctoral fellowship from the Spanish Scientific Research Council (CSIC). M. I. G. has a `Ramon y Cajal' contract funded by the Ministry of Science and Innovation. C. E. has a `Miguel Servet' contract funded by the Fondo de Investigacion Sanitaria. Both CIBERER and CIBERNED are initiatives from the Instituto de Salud Carlos III. We are grateful to patients and their families for their kind collaboration. We thank B. Alarcón for his technical assistance and also anonymous reviewers for their invaluable insight and suggestionsLupo, V.; Galindo, MI.; Martínez-Rubio, D.; Sevilla, T.; Vílchez, JJ.; Palau, F.; Espinós-Armero, CÁ. (2009). Missense mutations in the SH3TC2 protein causing Charcot-Marie-Tooth disease type 4C affect its localization in the plasma membrane and endocytic pathway. Human Molecular Genetics. 18(23):4603-4614. https://doi.org/10.1093/hmg/ddp42746034614182

The p.R1109X mutation in SH3TC2 gene is predominant in Spanish Gypsies with Charcot-Marie-Tooth disease type 4

[EN] Charcot-Marie-Tooth (CMT) disease type 4 (CMT4) is the name given to autosomal recessive forms of hereditary motor and sensory neuropathy (HMSN). When we began this study, three genes or loci associated with inherited peripheral neuropathies had already been identified in the European Gypsy population: HMSN-Lom (MIM 601455), HMSN-Russe (MIM 605285) and the congenital cataracts facial dysmorphism neuropathy syndrome (MIM 604168). We have carried out genetic analyses in a series of 20 Spanish Gypsy families diagnosed with a demyelinating CMT disease compatible with an autosomal recessive trait. We found the p.R148X mutation in the N-myc downstream-regulated gene 1 gene to be responsible for the HMSN-Lom in four families and also possible linkage to the HMSN-Russe locus in three others. We have also studied the CMT4C locus because of the clinical similarities and showed that in 10 families, the disease is caused by mutations located on the SH3 domain and tetratricopeptide repeats 2 (SH3TC2) gene: p.R1109X in 20 out of 21 chromosomes and p.C737_P738delinsX in only one chromosome. Moreover, the SH3TC2 p.R1109X mutation is associated with a conserved haplotype and, therefore, may be a private founder mutation for the Gypsy population. Estimation of the allelic age revealed that the SH3TC2 p.R1109X mutation may have arisen about 225 years ago, probably as the consequence of a bottleneck.We are grateful for the kind collaboration of patients and families. This work was supported by the Fondo de Investigacio¿n Sanitaria (grant PI040932) and the Spanish Network on Cerebellar Ataxias of the Instituto de Salud Carlos III (grant G03/56). English text was revised by F Barraclough.Claramunt, R.; Sevilla, T.; Lupo, V.; Cuesta, A.; Millán, J.; Vilchez, JJ.; Palau, F.... (2007). The p.R1109X mutation in SH3TC2 gene is predominant in Spanish Gypsies with Charcot-Marie-Tooth disease type 4. Clinical Genetics. 71(4):343-349. https://doi.org/10.1111/j.1399-0004.2007.00774.x34334971

Ancient origin of the CAG expansion causing Huntingtons disease in a Spanish population.

[EN] Huntington disease (HD) is an autosomal dominant neurodegenerative disorder characterized clinically by progressive motor impairment, cognitive decline, and emotional deterioration. The disease is caused by the abnormal expansion of a CAG trinucleotide repeat in the first exon of the huntingtin gene in chromosome 4p16.3. HD is spread worldwide and it is generally accepted that few mutational events account for the origin of the pathogenic CAG expansion in most populations. We have investigated the genetic history of HD mutation in 83 family probands from the Land of Valencia, in Eastern Spain. An analysis of the HD/CCG repeat in informative families suggested that at least two main chromosomes were associated in the Valencian population, one associated with allele 7 (77 mutant chromosomes) and one associated with allele 10 (two mutant chromosomes). Haplotype A-7-A (H1) was observed in 47 out of 48 phase-known mutant chromosomes, obtained by segregation analysis, through the haplotype analysis of rs1313770-HD/CCG-rs82334, as it also was in 120 out of 166 chromosomes constructed by means of the PHASE program. The genetic history and geographical distribution of the main haplotype H1 were both studied by constructing extended haplotypes with flanking short tandem repeats (STRs) D4S106 and D4S3034. We found that we were able to determine the age of the CAG expansion associated with the haplotype H1 as being between 4,700 and 10,000 years ago. Furthermore, we observed a nonhomogenous distribution in the different regions associated with the different extended haplotypes of the ancestral haplotype H1, suggesting that local founder effects have occurred.We are grateful for the kind collaboration of patients and families. This work was supported by the Fondo de investigación Sanitaria (FIS grant 01/1159), the Instituto de Salud Carlos III (grant G03/56) for the Spanish Network on Cerebellar Ataxias, and the Generalitat Valenciana (grant GRUPOS03/015).García-Planells, J.; Burguera, JA.; Solís, P.; Millán, JM.; Ginestar Peiro, D.; Palau, F.; Espinós-Armero, CÁ. (2005). Ancient origin of the CAG expansion causing Huntingtons disease in a Spanish population. Human Mutation. 25(5):453-459. https://doi.org/10.1002/humu.2016745345925

Genetic epidemiology of the Charcot-Marie-Tooth in the Spanish Gypsy population: the Hereditary Motor and Sensory Neuropathy type Russe in depth

[EN] Four private mutations responsible for three forms demyelinating of Charcot-Marie-Tooth (CMT) or hereditary motor and sensory neuropathy (HMSN) have been associated with the Gypsy population: the NDRG1 p.R148X in CMT type 4D (CMT4D/HMSN-Lom); p.C737_P738delinsX and p.R1109X mutations in the SH3TC2 gene (CMT4C); and a G>C change in a novel alternative untranslated exon in the HK1 gene causative of CMT4G (CMT4G/HMSN-Russe). Here we address the findings of a genetic study of 29 Gypsy Spanish families with autosomal recessive demyelinating CMT. The most frequent form is CMT4C (57.14%), followed by HMSN-Russe (25%) and HMSN-Lom (17.86%). The relevant frequency of HMSN-Russe has allowed us to investigate in depth the genetics and the associated clinical symptoms of this CMT form. HMSN-Russe probands share the same haplotype confirming that the HK1 g.9712G>C is a founder mutation, which arrived in Spain around the end of the 18th century. The clinical picture of HMSN-Russe is a progressive CMT disorder leading to severe weakness of the lower limbs and prominent distal sensory loss. Motor nerve conduction velocity was in the demyelinating or intermediate range.We thank all patients and their relatives for their kind collaboration. We also thank Drs G. Glover, R. Vilches, F. Galan, and C. Diaz for referring patients for genetic analysis. We also acknowledge F Barraclough for English corrections. This work was supported by the Instituto de Salud Carlos III (ISCIII) (grants number PI08/90857, PI08/0889, CP08/00053 and PS09/00095) co-funded with FEDER funds and by the ISCIII-IRDiRC Programme (TREAT-CMT grant). C. E. has a 'Miguel Servet' contract funded by the ISCIII. Both Centro de Investigacion Biomedica en Red de Enfermedades Raras (CIBERER) and Centro de Investigacion Biomedica en Red de Enfermedades Neurodegenerativas (CIBERNED) are initiative from the ISCIII.Sevilla, T.; Martínez-Rubio, D.; Márquez, C.; Paradas, C.; Colomer, J.; Jaijo, T.; Millán, J.... (2013). Genetic epidemiology of the Charcot-Marie-Tooth in the Spanish Gypsy population: the Hereditary Motor and Sensory Neuropathy type Russe in depth. Clinical Genetics. 83(6):565-570. https://doi.org/10.1111/cge.1201556557083