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BACKGROUND: Non-photosensitive trichothiodystrophies (TTDs) are a diverse group of genodermatoses within the subset of conditions known as "sulphur-deficient brittle hair" syndromes. A part of them has only recently been identified, revealing novel causative genes and very rare phenotypes of these genetic skin disorders. At the same time, the molecular basis of previously published and unresolved cases has been revealed through the introduction of innovative genetic techniques. We have previously described the facial phenotype of patients with the Photosensitive form of TTD during childhood. This study marks the beginning of an effort to expand the analysis to include individuals of the same age who do not have photosensitivity. METHODS: A total of 26 facial portraits of TTD paediatric patients with Non-photosensitivity from the literature were analysed using computer-aided technologies, and their facial features were examined through a detailed clinical review. RESULTS: Distinct facial features were identified in both Photosensitive and Non-photosensitive TTDs. CONCLUSION: The present study has comprehensively elucidated the facial features in TTDs, encompassing the Non-photosensitive clinical spectrum.
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Fenótipo , Síndromes de Tricotiodistrofia , Humanos , Síndromes de Tricotiodistrofia/genética , Síndromes de Tricotiodistrofia/patologia , Criança , Masculino , Feminino , Pré-Escolar , Adolescente , Face/anormalidades , Face/patologia , LactenteRESUMO
INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is a heart disorder caused by autosomal dominant alterations affecting both sarcomeric genes and other nonsarcomeric loci in a minority of cases. However, in some patients, the occurrence of the causal pathogenic variant or variants in homozygosity, compound heterozygosity, or double heterozygosity has also been described. Most of the HCM pathogenic variants are missense and unique, but truncating mutations of the MYBPC3 gene have been reported as founder pathogenic variants in populations from Finland, France, Japan, Iceland, Italy, and the Netherlands. OBJECTIVES: This study aimed to assess the genetic background of HCM in a cohort of Polish patients. PATIENTS AND METHODS: Twentynine Polish patients were analyzed by a next generation sequencing panel including 404 cardiovascular genes. RESULTS: Pathogenic variants were found in 41% of the patients, with ultra rare MYBPC3 c.2541C>G (p.Tyr847Ter) mutation standing for a variant hotspot and correlating with a lower age at HCM diagnosis. Among the nonsarcomeric genes, the CSRP3 mutation was found in a single case carrying the novel c.364C>T (p.Arg122Ter) variant in homozygosity. With this finding, the total number of known HCM cases with human CSRP3 knockout cases has reached 3. CONCLUSIONS: This report expands the mutational spectrum and the inheritance pattern of HCM.
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Cardiomiopatia Hipertrófica/genética , Proteínas de Transporte/genética , Proteínas com Domínio LIM/genética , Proteínas Musculares/genética , Mutação , Adolescente , Adulto , Idoso , Cardiomiopatia Hipertrófica/metabolismo , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Polônia , Adulto JovemRESUMO
BACKGROUND/AIMS: Truncating LMNA gene mutations occur in many inherited cardiomyopathy cases, but the molecular mechanisms involved in the disease they cause have not yet been systematically investigated. Here, we studied a novel frameshift LMNA variant (p.D243Gfs*4) identified in three members of an Italian family co-segregating with a severe form of cardiomyopathy with conduction defects. METHODS: HEK293 cells and HL-1 cardiomyocytes were transiently transfected with either Lamin A or D243Gfs*4 tagged with GFP (or mCherry). D243Gfs*4 expression, cellular localization and its effects on diverse cellular mechanisms were evaluated with western blotting, laser-scanning confocal microscopy and video-imaging analysis in single cells. RESULTS: When expressed in HEK293 cells, GFP- (or mCherry)-tagged LMNA D243Gfs*4 colocalized with calnexin within the ER. ER mislocalization of LMNA D243Gfs*4 did not significantly induce ER stress response, abnormal Ca2+ handling and apoptosis when compared with HEK293 cells expressing another truncated mutant of LMNA (R321X) which similarly accumulates within the ER. Of note, HEK293-LMNA D243Gfs*4 cells showed a significant reduction of connexin 43 (CX43) expression level, which was completely rescued by activation of the WNT/ß-catenin signaling pathway. When expressed in HL-1 cardiomyocytes, D243Gfs*4 significantly impaired the spontaneous Ca2+ oscillations recorded in these cells as result of propagation of the depolarizing waves through the gap junctions between non-transfected cells surrounding a cell harboring the mutation. Furthermore, mCh-D243Gfs*4 HL-1 cardiomyocytes showed reduced CX43-dependent Lucifer Yellow (LY) loading and propagation. Of note, activation of ß-catenin rescued both LY loading and LMNA D243Gfs*4 -HL-1 cells spontaneous activity propagation. CONCLUSION: Overall, the present results clearly indicate the involvement of the aberrant CX43 expression/activity as a pathogenic mechanism for the conduction defects associated to this LMNA truncating alteration.
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Doença do Sistema de Condução Cardíaco/genética , Cardiomiopatias/genética , Lamina Tipo A/genética , Apoptose , Sequência de Bases , Cálcio/metabolismo , Calnexina/metabolismo , Doença do Sistema de Condução Cardíaco/complicações , Doença do Sistema de Condução Cardíaco/patologia , Cardiomiopatias/complicações , Cardiomiopatias/patologia , Linhagem Celular , Conexina 43 , Retículo Endoplasmático/metabolismo , Feminino , Junções Comunicantes/metabolismo , Células HEK293 , Humanos , Lamina Tipo A/metabolismo , Repetições de Microssatélites/genética , Microscopia Confocal , Pessoa de Meia-Idade , Mutagênese Sítio-Dirigida , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Linhagem , Polimorfismo de Nucleotídeo Único , Imagem com Lapso de Tempo , Via de Sinalização WntRESUMO
BACKGROUND: Danon disease (DD) is a rare disorder characterized by cardiomyopathy, intellectual disability, and proximal myopathy. It is caused by mutations in the LAMP2 gene on X chromosome. Female patients most often present with late-onset cardiomyopathy and slow disease progression, but early-onset cases with unfavorable prognosis have been reported. CASE REPORT: We describe the clinical, pathological, and molecular features of a novel LAMP2 c.453delT mutation in a female patient with severe hypertrophic cardiomyopathy, Wolff Parkinson White (WPW) syndrome and rapid progression to heart failure, requiring heart transplant. Immunohistochemical analysis of LAMP2 in the explanted heart revealed a mosaic pattern of distribution, with discrete clusters of either stained or unstained cardiac myocytes, the latter being more frequent in the septum. These findings paralleled X chromosome inactivation within the myocardium. Interestingly, multiple foci of microscarring were found on histology in the Left Ventricle (LV) free wall and septum, in a close spatial relationship with remodeling and severe stenosis of intramural coronary arterioles. CONCLUSIONS: Our findings suggest that several features may contribute to the early and severe cardiac phenotype in female DD patients. The type of mutation may account for the early disease onset, while both the inhomogeneous distribution of LAMP2 loss and the presence of microvascular remodeling may be determinant in the rapid progression to heart failure.
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Cardiomegalia/genética , Doença de Depósito de Glicogênio Tipo IIb/genética , Proteína 2 de Membrana Associada ao Lisossomo/genética , Mutação , Cardiomegalia/patologia , Cardiomegalia/fisiopatologia , Feminino , Estudos de Associação Genética , Doença de Depósito de Glicogênio Tipo IIb/patologia , Doença de Depósito de Glicogênio Tipo IIb/fisiopatologia , Humanos , Síndrome de Wolff-Parkinson-White/genéticaRESUMO
Genomic technologies are redefining the understanding of genotype-phenotype relationships and over the past decade, many bioinformatics algorithms have been developed to predict functional consequences of single nucleotide variants. This article presents the data from a comprehensive computational workflow adopted to assess the biomedical impact of the DNA variants resulting from the experimental study "Molecular analysis of sarcomeric and non-sarcomeric genes in patients with hypertrophic cardiomyopathy" (Bottillo et al., 2016) [1]. Several different independently methods were employed to predict the functional consequences of alleles that result in amino acid substitutions, to study the effect of some DNA variants over the splicing process and to investigate the impact of a sequence variant with respect to the evolutionary conservation.
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BACKGROUND: Hypertrophic cardiomyopathy (HCM) is a common genetic heart disorder characterized by unexplained left ventricle hypertrophy associated with non-dilated ventricular chambers. Several genes encoding heart sarcomeric proteins have been associated to HCM, but a small proportion of HCM patients harbor alterations in other non-sarcomeric loci. The variable expression of HCM seems influenced by genetic modifier factors and new sequencing technologies are redefining the understanding of genotype-phenotype relationships, even if the interpretations of the numerous identified variants pose several challenges. METHODS AND RESULTS: We investigated 62 sarcomeric and non-sarcomeric genes in 41 HCM cases and in 3 HCM-related disorders patients. We employed an integrated approach that combines multiple tools for the prediction, annotation and visualization of functional variants. Genotype-phenotype correlations were carried out for inspecting the involvement of each gene in age onset and clinical variability of HCM. The 80% of the non-syndromic patients showed at least one rare non-synonymous variant (nsSNV) and among them, 58% carried alterations in sarcomeric loci, 14% in desmosomal and 7% in other non-sarcomeric ones without any sarcomere change. Statistical analyses revealed an inverse correlation between the number of nsSNVs and age at onset, and a relationship between the clinical variability and number and type of variants. CONCLUSIONS: Our results extend the mutational spectrum of HCM and contribute in defining the molecular pathogenesis and inheritance pattern(s) of this condition. Besides, we delineate a specific procedure for the identification of the most likely pathogenetic variants for a next generation sequencing approach embodied in a clinical context.