Atypical fundoscopic manifestation with good visual prognosis in familial hypomagnesemia with hypercalciuria and nephrocalcinosis.

PURPOSE: Pathogenic variants in the CLDN19 gene are responsible for Familial Hypomagnesemia with Hypercalciuria and Nephrocalcinosis (FHHNC) with ocular pathology (MIM *248190). Our objective was to delineate the ophthalmological and genetic manifestations of a patient with FHHNC and a pathogenic variant in CLDN19. CASE REPORT: A 25-year-old woman presented with renal involvement and a best-corrected visual acuity of 20/25 in the right eye and finger-counting ability in the left eye. The patient exhibited high myopia, convergent strabismus, and chorioretinal atrophic plaques in the perifoveal and peripapillary areas. We conducted a comprehensive ophthalmological examination, including refraction, fundoscopy, color and autofluorescence retinography, optical coherence tomography, and electrophysiology tests. Additionally, next-generation sequencing was performed using Illumina NextSeq500. We identified a homozygous missense variant, c.59G>A p.Gly20Asp, in the CLDN19 gene as the cause of renal and ocular manifestations. CONCLUSION: FHHNC is associated with various ocular alterations. The unique retinal disorders described in this article suggest a more favorable visual prognosis compared to those previously reported in the literature. Determining the phenotypic diversity of this disease may aid in the diagnosis and management of future cases.

LncRNA LUCAT1 as a novel prognostic biomarker for patients with papillary thyroid cancer.

In recent years, long non-coding RNAs have emerged as a novel class of regulators of cancer biological processes. While they are dysregulated in many cancer types, little is known about their expression and functional profiles. This study has been focused on the determination of the role of a specific lncRNA in papillary thyroid cancer. Quantitative reverse transcription PCR was performed to detect the expression levels of 84 lncRNAs in 61 papillary thyroid carcinoma tissues and their adjacent non-tumor tissues. The highest fold-change was obtained for lung cancer associated transcript 1 LUCAT1, and thus, this study determines the expression and biological implication of lncRNA LUCAT1 through different in vitro and ex vivo approaches in this tumor. LUCAT1 was specifically located at the cell nucleus in tumoral regions of patient tissues. Furthermore, LUCAT1 knockdown significantly reduced both cell proliferation and invasion ex vivo and induced cell-cycle arrest and apoptosis. These facts were corroborated by an enhanced expression of P21, P57, P53 and BAX, and a reduced expression of EZH2 and HDAC1. In addition, a significant decrease was observed on DNMT1 and NRF2 genes, helping to clarify the role of LUCAT1 on PTC. Our study reveals the involvement of LUCAT1 in PTC development, through acting in cell-cycle regulation, proliferation, epigenetic modifications through LUCAT1/ CDK1/ EZH2/ P57/ P21/ HDAC1/ DNMT1/ P53/ BAX axis and apoptosis, via extrinsic pathway activating caspases. These findings indicate that LUCAT1 is maybe a potential therapeutic target and molecular biomarker for PTC.

Epigenetics in ENS development and Hirschsprung disease.

Hirschsprung disease (HSCR, OMIM 142623) is a neurocristopathy caused by a failure of the enteric nervous system (ENS) progenitors derived from neural crest cells (NCCs), to migrate, proliferate, differentiate or survive to and within the gastrointestinal tract, resulting in aganglionosis in the distal colon. The formation of the ENS is a complex process, which is regulated by a large range of molecules and signalling pathways involving both the NCCs and the intestinal environment. This tightly regulated process needs correct regulation of the expression of ENS specific genes. Alterations in the expression of these genes can have dramatic consequences. Several mechanisms that control the expression of genes have been described, such as DNA modification (epigenetic mechanisms), regulation of transcription (transcription factor, enhancers, repressors and silencers), post-transcriptional regulation (3'UTR and miRNAs) and regulation of translation. In this review, we focus on the epigenetic DNA modifications that have been described so far in the context of the ENS development. Moreover we describe the changes that are found in relation to the onset of HSCR.

[Intrauterine myelomeningocele repair: experience of the fetal medicine and therapy program of the Virgen de Rocío University Hospital]. / Corrección intrauterina de mielomeningocele: experiencia del programa de medicina y terapia fetal del Hospital Universitario Virgen del Rocío.

The most frequent form of spina bifida is myelomeningocele. There is no optimal postnatal treatment for this defect. In addition to the motor or sensory deficits, which depend on the location of the lesion, the defect is usually associated with Chiari ii malformation in affected children. Myelomeningocele has high mortality and, in up to 80% to 90% of patients, can be accompanied by hydrocephalus, which causes severe neurocognitive impairment and requires the patient to be shunted for survival. Intrauterine repair of fetal malformations employing open access through hysterotomy has become a therapeutic option due to improved anesthetic and surgical techniques and instrumentation, which have allowed this type of intervention to become relatively frequent. Anesthetic treatment should focus on both the mother and fetus and the hemodynamic factors regulating placental flow, uterine dynamics, blood loss and fetal well-being must remain well-controlled. Within our Program for Fetal Medicine and Therapy, 21 open fetal interventions have been performed: 17 EXIT procedures and 4 procedures for the intrauterine correction of fetal myelomeningocele. We describe our experience of the intrauterine repair of fetal myelomeningocele through open fetal surgery.

Contribution of RET, NTRK3 and EDN3 to the expression of Hirschsprung disease in a multiplex family.

BACKGROUND: Hirschsprung disease (HSCR) is a developmental disorder caused by a defect in the neural crest neuroblast migration process. It is considered to be a paradigm of complex disorders, with many loci contributing to manifestation of the disease. Although HSCR commonly appears as a sporadic trait, approximately 20% of HSCR cases are familial, with complex patterns of inheritance. METHOD: A multiplex HSCR family with an additive model of inheritance, in which the contribution of three genes (RET, NTRK3, EDN3) leads to the HSCR phenotype is reported. RESULTS AND DISCUSSION: The findings suggest that both RET and NTRK3 mutations acting together are necessary and sufficient for the appearance of the disease, and that the EDN3 mutation is acting as a phenotype-modifier factor in the context of this family, as two different HSCR phenotypes are seen among the affected members: a short segment form, and a total colonic aganglionosis. The results therefore support the complex additive model of inheritance previously proposed for Hirschsprung disease.

A novel point variant in NTRK3, R645C, suggests a role of this gene in the pathogenesis of Hirschsprung disease.

Hirschsprung disease (HSCR) is a developmental disorder characterized by the absence of ganglion cells in the myenteric and submucosal plexuses due to a defect in the migration process of neural crest neuroblasts. Manifestation of the disease has been linked to the dysfunction of two principal signalling pathways involved in the enteric nervous system (ENS) formation: the RET-GDNF and the EDN3-EDNRB receptor systems. However, the NTF3/NTRK3 signalling pathway plays an essential role in the development of the ENS suggesting a potential role for those genes in the pathogenesis of HSCR. We have sought to evaluate the candidature of the NTRK3 gene, which encodes the TrkC receptor, as a susceptibility gene for Hirschsprung disease. Using dHPLC technology we have screened the NTRK3 coding region in 143 Spanish HSCR patients. A total of four previously described polymorphisms and 12 novel sequence variants were detected. Of note, the novel R645C mutation was detected in 2 affected siblings of a HSCR family also carrying a RET splicing mutation. Using bioinformatics tools we observed that the presence of an additional cysteine residue might implicate structural alterations in the mutated protein. We propose haploinsufficiency as the most probable mechanism for the NTRK3 R645C mutation. NTRK3 and RET mutations in this family only appear together in the HSCR patients, suggesting that they per se are necessary but not sufficient to produce the phenotype. In addition, it is quite probable that the contribution of other still unidentified modifier genes, may be responsible for the different phenotypes (length of aganglionosis) in the two affected members.

Linkage validation of RP25 Using the 10K genechip array and further refinement of the locus by new linked families.

Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal dystrophies, characterised by rod photoreceptor cell degeneration with autosomal recessive RP (arRP) as the commonest form worldwide. To date, a total of 26 loci have been reported for arRP, each having a prevalence of 1-5%, except for the RP25 locus which was identified as the genetic cause of 14% of arRP cases in Spain. In order to validate the original linkage of RP25, we undertook a total genome scan using the 10K GeneChip mapping array on three of the previously linked families. The data obtained supported the initial findings of linkage. Additionally, linkage analysis in 18 newly ascertained arRP families was performed using microsatellite markers spanning the chromosome 6p12.1-q15 interval. Five out of the 18 families showed suggestive evidence of linkage to RP25, hence supporting the high prevalence of this locus in the Spanish population. Furthermore, the finding of a crossover in one of these families is likely to have refined the disease interval from the original 16 cM to only a 2.67 cM region between D6S257 and D6S1557.

Large-scale molecular analysis of a 34 Mb interval on chromosome 6q: major refinement of the RP25 interval.

A large scale bioinformatics and molecular analysis of a 34 Mb interval on chromosome 6q12 was undertaken as part of our ongoing study to identify the gene responsible for an autosomal recessive retinitis pigmentosa (arRP) locus, RP25. Extensive bioinformatics analysis indicated in excess of 110 genes within the region and we also noted unfinished sequence on chromosome 6q in the Human Genome Database, between 58 and 61.2 Mb. Forty three genes within the RP25 interval were considered as good candidates for mutation screening. Direct sequence analysis of the selected genes in 7 Spanish families with arRP revealed a total of 244 sequence variants, of which 67 were novel but none were pathogenic. This, together with previous reports, excludes 60 genes within the interval ( approximately 55%) as disease causing for RP. To investigate if copy number variation (CNV) exists within RP25, a comparative genomic hybridization (CGH) analysis was performed on a consanguineous family. A clone from the tiling path array, chr6tp-19C7, spanning approximately 100-Kb was found to be deleted in all affected members of the family, leading to a major refinement of the interval. This will eventually have a significant impact on cloning of the RP25 gene.

Genetic analysis of FAM46A in Spanish families with autosomal recessive retinitis pigmentosa: characterisation of novel VNTRs.

Retinitis pigmentosa (RP) is a group of retinal dystrophies characterised primarily by rod photoreceptor cell degeneration. Exhibiting great clinical and genetic heterogeneity, RP be inherited as an autosomal dominant (ad) and recessive (ar), X-linked (xl) and digenic disorder. RP25, a locus for arRP, was mapped to chromosome 6p12.1-q14.1 where several retinal dystrophy loci are located. A gene expressed in the retina, FAM46A, mapped within the RP25 locus, and computational data revealed its involvement in retinal signalling pathways. Therefore, we chose to perform molecular evaluation of this gene as a good candidate in arRP families linked to the RP25 interval. A comprehensive bioinformatic and retinal tissue expression characterisation of FAM46A was performed, together with mutation screening of seven RP25 families. Herein we present 4 novel sequence variants, of which one is a novel deletion within a low complexity region close to the initiation codon of FAM46A. Furthermore, we have characterised for the first time a coding tandem variation in the Caucasian population. This study reports on bioinformatic and moleculardata for the FAM46A gene that may give a wider insight into the putative function of this gene and its pathologic relevance to RP25 and other retinal diseases mapping within the 6q chromosomal interval.

Hirschsprung disease, associated syndromes and genetics: a review.

Hirschsprung disease (HSCR, aganglionic megacolon) represents the main genetic cause of functional intestinal obstruction with an incidence of 1/5000 live births. This developmental disorder is a neurocristopathy and is characterised by the absence of the enteric ganglia along a variable length of the intestine. In the last decades, the development of surgical approaches has importantly decreased mortality and morbidity which allowed the emergence of familial cases. Isolated HSCR appears to be a non-Mendelian malformation with low, sex-dependent penetrance, and variable expression according to the length of the aganglionic segment. While all Mendelian modes of inheritance have been described in syndromic HSCR, isolated HSCR stands as a model for genetic disorders with complex patterns of inheritance. The tyrosine kinase receptor RET is the major gene with both rare coding sequence mutations and/or a frequent variant located in an enhancer element predisposing to the disease. Hitherto, 10 genes and five loci have been found to be involved in HSCR development.

A novel genetic study of Chinese families with autosomal recessive retinitis pigmentosa.

Autosomal recessive retinitis pigmentosa (arRP) is the commonest form of RP worldwide. To date 22 loci have been implicated in the pathogenesis of this disease; however none of these loci independently account for a significant proportion of recessive RP. Linkage studies of arRP in consanguineous families have been mainly based on homozygosity mapping, but this strategy cannot be applied in the case of non-consanguineous families. Therefore, we implemented a systematic approach for identifying the disease locus in three non-consanguineous Chinese families with arRP. Initially, linkage analysis using SNPs/microsatellite markers or mutation screening of known arRP genes excluded all loci/genes except RP25 on chromosome 6. Subsequently a whole genome scan for the three families using the 10K GeneChip Mapping Array was performed, in order to identify the possible disease locus. To the best of our knowledge this is the first report on the utilisation of the 10K GeneChip to study linkage in non-consanguineous Chinese arRP. This analysis indicates that the studied families are probably linked to the RP25 locus, a well defined arRP locus in other populations. The identification of another ethnic group linked to RP25 is highly suggestive that this represents a major locus for arRP.

Identification of 14 novel mutations in the long isoform of USH2A in Spanish patients with Usher syndrome type II.

Mutations in USH2A gene have been shown to be responsible for Usher syndrome type II, an autosomal recessive disorder characterised by hearing loss and retinitis pigmentosa. USH2A was firstly described as consisting of 21 exons, but 52 novel exons at the 3' end of the gene were recently identified. In this report, a mutation analysis of the new 52 exons of USH2A gene was carried out in 32 unrelated patients in which both disease-causing mutations could not be found after the screening of the first 21 exons of the USH2A gene. On analysing the new 52 exons, fourteen novel mutations were identified in 14 out of the 32 cases studied, including 7 missense, 5 frameshift, 1 duplication and a putative splice-site mutation.

Mutation profile of the MYO7A gene in Spanish patients with Usher syndrome type I.

Usher syndrome type I is the most severe form of Usher syndrome. It is an autosomal recessive disorder characterized by profound congenital sensorineural deafness, retinitis pigmentosa, and vestibular abnormalities. Mutations in the myosin VIIA gene (MYO7A) are responsible for Usher syndrome type 1B (USH1B). This gene is thought to bear greatest responsibility for USH1 and, depending on the study, has been reported to account for between 24% and 59% of USH1 cases. In this report a mutation screening of the MYO7A gene was carried out in a series of 48 unrelated USH1 families using single strand conformation polymorphism analysis (SSCP) and direct sequencing of those fragments showed an abnormal electrophoretic pattern. Twenty-five mutations were identified in 23 out of the 48 families studied (47.9%). Twelve of these mutations were novel, including five missense mutations, three premature stop codons, three frameshift, and one putative splice-site mutation. Based on our results we can conclude there is an absence of hot spot mutations in the MYO7A gene and that this gene plays a major role in Usher syndrome.

The -670A > G polymorphism in the promoter region of the FAS gene is associated with necrosis in periportal areas in patients with chronic hepatitis C.

Evidence suggests that apoptosis of liver cells may play a significant role in the pathogenesis of hepatitis C virus (HCV) infection. One of the best characterized apoptotic pathway is that mediated by the death receptor Fas. Fas expression has been found to be up-regulated on hepatocytes in chronic HCV infection, particularly in periportal areas. Recently, two polymorphisms have been identified in the promotor region of the FAS gene, -1377G > A and -670A > G. We have evaluated the involvement of these variants in the susceptibility to HCV infection, the severity of liver damage and progression of fibrosis in chronic hepatitis C. A cohort of 197 patients with chronic hepatitis C and 100 controls were analysed for both polymorphisms by Fluorescence Resonance Energy Transfer using specific probes and the Lightcycler system. In addition, liver biopsies were taken in 167 patients and scored using the Knodell classification system. We have found that the allele frequencies and the distribution of both polymorphisms do not differ significantly in the HCV cohort and in the control population. Thus, none of the polymorphisms seems to be related with susceptibility to HCV infection. However, we have examined the possible association between the two variants and the grade of necroinflammatory activity and the stage of fibrosis and we have detected an under-representation of the -670A > G variant among those patients with higher Knodell's scores (P = 0.049) and necroinflammatory activity (P = 0.036). The -670A allele was associated with higher levels of periportal necrosis (P = 0.012). In conclusion, our findings suggest an association between the -670A > G polymorphism and the grade of necrosis in periportal areas in patients with chronic hepatitis C.

Polymorphisms in the promoter regions of FAS and FASL genes as candidate genetic factors conferring susceptibility to endometriosis.

Although the pathophysiological mechanisms leading to endometriosis remain unknown, several hypothesis have been proposed, including a dysregulation of the normal apoptotic process which takes place in the endometrium. One of the apoptotic pathways playing a crucial role in the programmed cell death within the endometrium is the Fas-FasL system. In this study we have performed a case-control analysis in order to evaluate three polymorphisms located within FAS (-1377G>A and -670A>G) and FASL (-843C>T) genes, as susceptibility factors for endometriosis. We have analysed a series of women with endometriosis compared respectively to a group of women without symptoms of the disease, and to a group of confirmed unaffected women. The genotyping of the three variants was carried out by Fluorescence Resonance Energy Transfer (FRET) technology, and statistical analysis was performed using chi2 test with Yates correction. Our results show that the differences in the distribution of the polymorphic variants were not statistically significant when the group of patients was compared to the other groups. Thus, it seems to indicate that the variants here analysed are not involved in the pathogenesis of the disease in our population. However this does not let us to completely exclude such genes as potential candidates for the disease. A complete genetic analysis of the genes involved in the intricate regulatory system of the apoptosis may lead to the identification of susceptibility factors for the disease and a better understanding of its etiology.

Ancestral RET haplotype associated with Hirschsprung's disease shows linkage disequilibrium breakpoint at -1249.

BACKGROUND: Hirschsprung disease (HSCR) is a complex disorder with traditional germline mutations in RET in up to 30% of familial cases and in 3% of sporadic cases in a population-based series. We have previously demonstrated that an ancestral haplotype at the 5' end of RET (haplotype 0) was strongly associated with a large subset of isolated HSCR cases and that a putative low penetrance susceptibility locus was encompassed within this ancestral haplotype, anchored by exon 2 SNP A45A. OBJECTIVE: To determine the 5' extent of the HSCR-associated ancestral haplotype by defining the linkage disequilibrium breakpoint in search for the low penetrance susceptibility locus. METHODS: Systematic screening of the region upstream of the anchoring A45A SNP, comprising RET intron 1, exon 1, and promoter in 117 population-based HSCR cases and 100 controls. Dual luciferase assay to determine differential activities between SNP combinations near a transcription start site. RESULTS: New SNP's were found which formed upstream haplotypes, anchored by A45A, in linkage disequilibrium with HSCR (2 = 76.96, p<0.00000001). Linkage disequilibrium appeared to break at the -1249C/T SNP. Further, the HSCR-associated genotype (00) was found in >60% of HSCR but only 2% of controls. Because only 2 variants, -200A>G and -196C>A, lie within the promoter region and are in proximity to the transcriptional start site (at -195), we modelled these combinations into constructs for luciferase reporter assay. The HSCR-associated SNP combination showed the lowest activity and the control-associated combination, the highest. CONCLUSIONS: Our observations seem to discard the existence of a HSCR-causing mutation as it is conceived in the traditional sense, but strengthen the idea of a specific combination of variants conferring susceptibility to the disease in a low penetrance fashion. The data derived from our functional "in vitro" studies would suggest that the HSCR-associated haplotype 0 may result in a lower level of expression of the RET gene [corrected]

Spanish family with myalgia and cramps syndrome.

A Spanish family is reported with dystrophinopathy of myalgia and cramps syndrome type. There were five affected males and three females, and also six asymptomatic carriers. Muscle biopsy showed a dystrophic pattern, but immunohistochemistry carried out with three anti-dystrophin antibodies was normal. Dystrophin analysis by western blot revealed a dystrophin of reduced quantity and molecular weight. DNA analysis showed a deletion of the dystrophin gene involving exons 45-52. The natural history of this disorder and the large intrafamilial clinical variability are discussed.

Analysis of CCR5-Delta 32 and CCR2-V64I polymorphisms in a cohort of Spanish HCV patients using real-time polymerase chain reaction and fluorescence resonance energy transfer technologies.

Nowadays it is clear that chemokine-chemokine receptor interactions are important in chronic hepatitis C virus (HCV) infection. The objective of the present study was to elucidate the involvement of the CCR5-Delta 32 and CCR2-V64I polymorphisms in the response to the HCV infection, as well as in the histological damage and the outcome of the infection. A cohort of 139 patients with hepatitis C and 100 healthy blood donors were analysed for both polymorphisms using real-time polymerase chain reaction (PCR) and LightCycler technology. We have detected the CCR5-Delta 32 allele in 15 of 278 HCV chromosomes (5.4%) and 15 of 200 control chromosomes (7.5%). The CCR2-V64I allele was present in 24 of 278 HCV chromosomes (8.6%) and 19 of 200 control chromosomes (9.5%). Analysis of the histological parameters showed no statistical significance when comparing the patients carrying the variants vs the cases with the wild-type allele. Our results seem to indicate that the CCR5-Delta 32 and CCR2-V64I polymorphisms are not related to the response to HCV infection, histological damage and outcome of infection in our cohort of Spanish HCV patients.