RESUMO
Syndromic retinal diseases (SRDs) are a group of complex inherited systemic disorders, with challenging molecular underpinnings and clinical management. Our main goal is to improve clinical and molecular SRDs diagnosis, by applying a structured phenotypic ontology and next-generation sequencing (NGS)-based pipelines. A prospective and retrospective cohort study was performed on 100 probands with an a priori diagnosis of non-Usher SRDs, using available clinical data, including Human Phenotype Ontology annotation, and further classification into seven clinical categories (ciliopathies, specific syndromes and five others). Retrospective molecular diagnosis was assessed using different molecular and bioinformatic methods depending on availability. Subsequently, uncharacterized probands were prospectively screened using other NGS approaches to extend the number of analyzed genes. After phenotypic classification, ciliopathies were the most common SRD (35%). A global characterization rate of 52% was obtained, with six cases incompletely characterized for a gene that partially explained the phenotype. An improved characterization rate was achieved addressing prospective cases (83%) and well-recognizable syndrome (62%) subgroups. The 27% of the fully characterized cases were reclassified into a different clinical category after identification of the disease-causing gene. Clinical-exome sequencing is the most appropriate first-tier approach for prospective cases, whereas whole-exome sequencing and bioinformatic reanalysis increases the diagnosis of uncharacterized retrospective cases to 45%, mostly those with unspecific symptoms. Our study describes a comprehensive approach to SRDs in daily clinical practice and the importance of thorough clinical assessment and selection of the most appropriate molecular test to be used to solve these complex cases and elucidate novel associations.
Assuntos
Oftalmopatias Hereditárias/diagnóstico , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala , Doenças Retinianas/diagnóstico , Ciliopatias/genética , Estudos de Coortes , Oftalmopatias Hereditárias/genética , Feminino , Estudos de Associação Genética , Testes Genéticos , Humanos , Masculino , Técnicas de Diagnóstico Molecular , Mutação , Fenótipo , Estudos Prospectivos , Doenças Retinianas/genética , Estudos Retrospectivos , SíndromeRESUMO
The disorders caused by mutations in genes encoding subunits and accessory proteins of cohesin complex are collectively termed as cohesinopathies. The best known cohesinopathy is Cornelia de Lange Syndrome (CdLS), which is a multisystem developmental disorder characterized by facial dysmorphism, limb malformations, growth and cognitive impairment. Mutations in five genes, encoding subunits of the cohesin complex (SMC1A, SMC3, RAD21) and its regulators (NIPBL, HDAC8), are responsible for â¼ 70% of CdLS cases. We describe a 16-year-old boy with facial dysmorphism, growth retardation, intellectual disability, hirsutism and small hands, who has a small Supernumerary Marker Chromosome (sSMC) present in mosaic form. sSMC is composed of two duplicated segments encompassing 17 genes including SMC1A gene, at the regions Xp11.22 and Xp11.21q11.1. Clinical comparison between our patient with a previously reported individual with a SMC1A duplication and four male carriers of similar sSMC reported in databases, suggest that they all share clinical features related to cohesinopathies. Although our patient does not have the classical CdLS craniofacial phenotype, he has pre and postnatal growth retardation, intellectual disability and mild musculoskeletal anomalies, features commonly seen in patients with cohesinopathies.
Assuntos
Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Síndrome de Cornélia de Lange/genética , Deficiência Intelectual/genética , Adolescente , Cromossomos Humanos X , Síndrome de Cornélia de Lange/fisiopatologia , Genes Duplicados , Humanos , Deficiência Intelectual/fisiopatologia , Masculino , Fenótipo , CoesinasRESUMO
The existence of foetal DNA in maternal blood, discovered in 1997, opened new possibilities for noninvasive prenatal diagnosis. This includes foetal sex assessment by the detection of specific Y chromosome sequences in maternal blood, particularly important when a foetus may be affected by an X-linked disorder such as haemophilia. This study aims to validate this sex assessment method and to test its clinical utility in the diagnosis of 15 potentially affected pregnancies in female carriers of haemophilia. In the validation study, 316 maternal blood samples from 196 pregnant women at gestations ranging from 5 weeks to 12 weeks were analysed. In the clinical study, 15 pregnancies at risk of having a haemophilic foetus were tested. All pregnancies in the validation study were correctly diagnosed. The accuracy and specificity of the methodology from the seventh week of gestation was 100%. The sex of all 15 pregnancies identified as being at risk of bearing a haemophilic foetus was correctly diagnosed. Foetal sex assessment by detecting specific Y chromosome sequences in maternal blood is now routinely used in our hospital because of its high accuracy from the seventh week of gestation. Reliable foetal gender determination from maternal blood of pregnant women carriers of haemophilia in the first trimester of gestation can avoid more conventional, invasive methods of prenatal diagnosis.
Assuntos
Doenças Fetais/diagnóstico , Hemofilia A/diagnóstico , Diagnóstico Pré-Natal/métodos , Análise para Determinação do Sexo/métodos , Cromossomos Humanos Y/genética , DNA/sangue , Feminino , Idade Gestacional , Hemofilia A/sangue , Heterozigoto , Humanos , Masculino , Reação em Cadeia da Polimerase , Gravidez , Primeiro Trimestre da Gravidez , Sensibilidade e EspecificidadeRESUMO
BACKGROUND AND PURPOSE: The presence of cell-free fetal DNA in maternal plasma could allow performing a non-invasive prenatal diagnosis of Huntington disease (HD). The great advantage of this diagnosis is the absence of risk of fetal loss that it entails. METHODS: Maternal plasma from four pregnant women in their first trimester of gestation with a fetus at-risk was studied. In all the four cases, the father was affected. RESULTS: The diagnosis was performed both by a direct study of the mutation and an indirect haplotype study. By the direct analysis, three out of the four fetuses could be correctly diagnosed whilst the indirect analysis was only conclusive in one case. CONCLUSIONS: Non-invasive prenatal diagnosis of HD is possible by the analysis of fetal DNA in maternal plasma. Direct analysis of the mutation has shown higher accuracy than the haplotype analysis except for long expansions. Haplotype analysis would need to be improved for the study of Juvenile-onset HD. This diagnostic method would be limited to those couples with an affected male however this situation represents 80-90% of the pregnancies at-risk of HD. Moreover, it could be used as a confirmation test of healthy embryos transferred on pre-implantation genetic studies of HD.
Assuntos
DNA/sangue , Doença de Huntington/diagnóstico , Diagnóstico Pré-Natal/métodos , Análise Mutacional de DNA/métodos , Feminino , Frequência do Gene , Predisposição Genética para Doença , Haplótipos , Humanos , Proteína Huntingtina , Doença de Huntington/genética , Padrões de Herança , Masculino , Repetições de Microssatélites , Mutação , Proteínas do Tecido Nervoso/genética , Proteínas Nucleares/genética , Linhagem , Valor Preditivo dos Testes , Gravidez , Primeiro Trimestre da Gravidez/sangue , Prognóstico , Repetições de TrinucleotídeosRESUMO
We report on a girl with minor anomalies and developmental delay carrying an apparently balanced paracentric inversion of chromosome 6q (q22qter). Fluorescent in situ hybridization analysis demonstrated a deletion of the subtelomeric region of 6q. This illustrates the use of specific subtelomeric fluorescent in situ hybridization probes to detect cryptic deletions as an important cause of mental retardation in seemingly balanced chromosome rearrangements.
Assuntos
Deleção Cromossômica , Inversão Cromossômica , Cromossomos Humanos Par 6/genética , Deficiência Intelectual/genética , Telômero/genética , Sondas de DNA , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Deficiência Intelectual/patologia , CariotipagemRESUMO
We present two siblings with retinitis pigmentosa, mental retardation, markedly short stature, and brachydactyly. This association of clinical findings appears to be distinct from previously described syndromes and seems to represent the pleiotropic effects of a single autosomal recessive gene.
Assuntos
Deformidades Congênitas do Pé/genética , Transtornos do Crescimento/genética , Deformidades Congênitas da Mão/genética , Deficiência Intelectual/genética , Retinose Pigmentar/genética , Adulto , Feminino , Deformidades Congênitas do Pé/patologia , Deformidades Congênitas da Mão/diagnóstico por imagem , Deformidades Congênitas da Mão/patologia , Humanos , Masculino , Pessoa de Meia-Idade , RadiografiaRESUMO
We present clinical and cytogenetic studies of a female patient affected with choroideremia, mild sensorineural deafness, and primary amenorrhea showing a balanced translocation between chromosomes X and 4. The breakpoint was precisely defined applying FISH techniques: 46,X,t(X;4)(q21.2;p16.3).ish t(X;4)(D4S96+, D4F26+; wcpX+). The X-chromosomal breakpoint was located within a region where both the choroideremia locus and a deafness locus (DFN3/POU3F4) have been mapped. The presence of X-linked disorders in this balanced carrier of X-autosomal translocations (XAT) can be explained either by the disruption of the structural coding or regulatory sequences of the gene(s) or by the submicroscopic deletion of this region leading to a contiguous gene deletion syndrome. The primary ovarian failure (POF) found in the present case has been already observed in XAT when the breakpoint is within a previously defined critical region (Xq13-26). A position effect is postulated as a possible explanation.
Assuntos
Coroideremia/genética , Surdez/genética , Perda Auditiva Neurossensorial/genética , Insuficiência Ovariana Primária/genética , Translocação Genética , Cromossomo X , Adulto , Coroideremia/complicações , Coroideremia/patologia , Bandeamento Cromossômico , Cromossomos Humanos Par 4 , Sondas de DNA , Surdez/complicações , Surdez/patologia , Feminino , Angiofluoresceinografia , Ligação Genética , Perda Auditiva Neurossensorial/complicações , Perda Auditiva Neurossensorial/patologia , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Masculino , Insuficiência Ovariana Primária/complicações , Insuficiência Ovariana Primária/patologiaRESUMO
We report two infertile brothers presenting with azoospermia and oligozoospermia. Cytogenetic studies using G-banding and FISH analysis on lymphocyte cultures revealed an autosomal balanced reciprocal translocation t(1;22)(q11;p11) in both males. The same translocation was found in their mother, but not in a third fertile brother and maternal uncle suggesting that this translocation might compromise the male but not the female gametogenesis in this family.
Assuntos
Cromossomos Humanos Par 11 , Cromossomos Humanos Par 1 , Oligospermia/genética , Translocação Genética , Adulto , Feminino , Humanos , Masculino , Mães , LinhagemRESUMO
A MELAS phenotype and a paternal inherited inversion of chromosome 10 in a female patient: We describe a patient suffering from encephalomyopathy with overlapping symptoms, including MELAS and Kearn-Sayre syndrome features. Mutations in tRNA LEU (UUR) were not found in mtDNA of blood cells, suggesting a different genetic defect. Cytogenetic studies revealed a paternal inherited pericentric inversion of chromosome 10 (p13;q22) pat. Although the presence of the same inversion in the father and in the apparently asymptomatic sister does rather suggest that the concurrence of the mitochondrial disease in the patient was due to chance, some alternative explanations to associate both events might be proposed.
Assuntos
Aberrações Cromossômicas/genética , Inversão Cromossômica , Cromossomos Humanos Par 10/genética , Síndrome MELAS/genética , Adulto , Biópsia , Quebra Cromossômica/genética , Transtornos Cromossômicos , Análise Mutacional de DNA , DNA Mitocondrial/genética , Feminino , Humanos , Encefalomiopatias Mitocondriais/genética , Músculo Esquelético/patologia , FenótipoRESUMO
Aniridia can arise as part of the WAGR syndrome (Wilms tumour. aniridia, genitourinary anomalies, and mental retardation), due to a deletion or chromosomal region 11p13. We report a girl with a complete WAGR syndrome, whose brother presented hypospadias. Cytogenetic, FISH and molecular studies showed a deletion in one chromosome 11 of the patient. No cytogenetic rearrangement or deletion affecting the genes included in this region (PAX6 and WT1) were observed in her brother and parents. This excludes a higher risk than that of the general population for developing Wilms tumour in the brother and supports that the presence of WAGR syndrome in the patient and hypospadias in her brother is a chance association. We conclude that the identification and definition of the deletions in the WAGR region, which include the WT1 locus are important in order to identify a high tumour risk in infant patients with aniridia including those without other WAGR anomalies.
Assuntos
Aniridia/patologia , Hipospadia/patologia , Síndrome WAGR/patologia , Aniridia/genética , Bandeamento Cromossômico , Deleção Cromossômica , Cromossomos Humanos Par 11 , Feminino , Humanos , Hipospadia/genética , Hibridização in Situ Fluorescente , Masculino , Síndrome WAGR/genéticaRESUMO
PURPOSE: We focused on the improvements of prenatal diagnosis by the analysis of DNA from maternal plasma, using Huntington disease as a model of disease. METHODS: We studied plasma from a pregnancy at risk of having a fetus affected with Huntington disease by the use of two direct analysis of the mutation and polymorphic STRs. RESULTS: Direct methods were not informative. Analysis with STRs revealed the presence of the allele that does not co-segregate with the disease, thus the fetus was healthy. CONCLUSIONS: This strategy is very useful to face complex cases when the direct study is not informative not only for Huntington disease but also for many other disorders.
Assuntos
DNA/sangue , Doença de Huntington/diagnóstico , Diagnóstico Pré-Natal , DNA/genética , Feminino , Humanos , Doença de Huntington/genética , Masculino , Repetições de Microssatélites , Mutação , GravidezRESUMO
Small supernumerary marker chromosomes are seldom found in prenatal diagnosis and the majority of them are difficult to identify. The only possibility to give a more precise prognosis is by establishing its origin. FISH is the best technique to identify the chromosomal origin, but in the majority of cases large amounts of chromosomal material are needed and this is time consuming. We have used a modification of the FISH technique that allows the hybridization of several probes on one slide. Using this method, we have identified the first de novo mosaic dicentric supernumerary marker derived from chromosome 16 (smaller than chromosome 21) in amniotic fluid. The gestation and the follow-up of the baby were normal.
Assuntos
Amniocentese , Aberrações Cromossômicas , Cromossomos Humanos Par 16 , Marcadores Genéticos , Hibridização in Situ Fluorescente , Adulto , Bandeamento Cromossômico , Feminino , Humanos , GravidezRESUMO
OBJECTIVE: To describe the ultrasound findings and its relationship with the cytogenetic study and the origin of the extra haploid chromosome set in four 69,XXX cases. METHODS: Four pregnant women were referred because of abnormal 2nd trimester ultrasound. Karytoypes, FISH and DNA analysis were performed. RESULTS: All cases presented asymmetrical intrauterine growth retardation, marked oligohydramnios and placental alterations and showed a 69,XXX karyotype. In three cases, DNA analysis allowed to establish the origin of the extra haploid chromosome set. CONCLUSIONS: At least three fetuses had a maternal extra haploid chromosome set. Thus, it has been possible to establish the main ultrasonographic markers and to observe the survival of the fetus until the second trimester when they have a maternal origin.
Assuntos
Análise Citogenética , DNA/análise , Idade Gestacional , Poliploidia , Ultrassonografia Pré-Natal , Cromossomo X , Adulto , Líquido Amniótico/química , Gonadotropina Coriônica Humana Subunidade beta/análise , Gonadotropina Coriônica Humana Subunidade beta/sangue , Amostra da Vilosidade Coriônica , Cromossomos Humanos Par 18 , Feminino , Retardo do Crescimento Fetal/genética , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Oligo-Hidrâmnio , Gravidez , alfa-Fetoproteínas/análiseRESUMO
The discovery of fetal DNA in maternal plasma from early pregnancies has led to new opportunities for clinical application. In the last few years there have been numerous reported applications, mainly fetal gender and RhD genotyping. The prenatal diagnosis of some inherited genetic diseases such as Huntington disease is also very frequently required in the prenatal diagnosis routine. We have successfully diagnosed, with a non-invasive procedure, an unaffected HD fetus at the 13th week of gestation using fetal DNA from maternal plasma and the quantitative fluorescent PCR method, which is one of the most sensitive ways to detect fetal DNA in maternal plasma at such an early time of gestation.
Assuntos
DNA/sangue , Doença de Huntington/diagnóstico , Doença de Huntington/genética , Reação em Cadeia da Polimerase , Diagnóstico Pré-Natal/métodos , Alelos , Amostra da Vilosidade Coriônica , DNA/análise , DNA/química , Feminino , Idade Gestacional , Humanos , Doença de Huntington/sangue , Masculino , Gravidez , Sequências Repetitivas de Ácido NucleicoRESUMO
It has been postulated that the deletion of band 13q22 may be associated with digital malformations, especially thumb and big toe anomalies. We report a family where the mother is carrying a balanced translocation between chromosomes 5p15 and 13q22. The offspring have a specific and well-defined phenotype depending on which is the unbalanced chromosome in the karyotype. When a partial trisomy of 13q22-->qter is present, the fetuses have polydactyly in the four limbs, and when the fetus is carrying a partial monosomy of this portion, an oligodactyly in all members can be observed.
Assuntos
Segregação de Cromossomos , Monossomia , Dedos do Pé/anormalidades , Translocação Genética , Trissomia , Cromossomos Humanos Par 13 , Cromossomos Humanos Par 5 , Feminino , Humanos , Linhagem , Polidactilia/genéticaRESUMO
A study of choroideremia gene was performed in Spanish families affected with this disorder. One abnormal pattern was detected in exon eight corresponding to a new mutation not described before. The mutation was identified as a nonsense mutation S340X.
Assuntos
Coroideremia/genética , Mutação/genética , Códon sem Sentido/genética , Humanos , EspanhaRESUMO
The authors report two new rare DNA sequence variants in the Rhodopsin gene. This gene is involved in the pathogenesis of some retinal hereditary disorders as Retinitis Pigmentosa. These rare variants are G-->A at nucleotide 721 of the non-coding region and C-->T at nucleotide 5200 within codon 323 which does not alter the aminoacid cysteine. Therefore, they are not implicated in the development of the Retinitis Pigmentosa disease.
Assuntos
Mutação Puntual/genética , Rodopsina/genética , Adenina , Citosina , Guanina , Humanos , Retinose Pigmentar/genética , TiminaRESUMO
Objectives- Several attempts have been made to determine the gestational period in which the maximum number of fetal cells can be found in maternal blood and consequently which is the best week in which to perform a reliable non-invasive prenatal diagnosis. Most studies conclude that the number of nucleated red blood cells (NRBC) increases in line with gestation, but the number of cells that are fetal in origin (FNRBC) decreases in the third trimester. The aim of the present study was to make a practical comparative evaluation of the first and second trimesters to ascertain the period in which a greater number of FNRBC can be found of the total number of NRBC identified. Methods- Double density gradient and a posterior positive selection (CD71) by magnetic activated cell sorting (MACS) were employed. In the final fraction, erythroblasts were identified using Kleihauer staining and were studied using the fluorescence in situ hybridization (FISH) interphasic technique. Results- There was a significant difference (p<0.05) between the mean number of FNRBC found in the first and second trimesters. Conclusions- The number of FNRBC increases from the first to the second trimester. It appears that the optimum week in which to perform a reliable non-invasive prenatal diagnosis is around the 15th week.
Assuntos
Eritroblastos , Sangue Fetal/citologia , Idade Gestacional , Hibridização in Situ Fluorescente , Primeiro Trimestre da Gravidez/sangue , Segundo Trimestre da Gravidez/sangue , Diagnóstico Pré-Natal/métodos , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , GravidezRESUMO
OBJECTIVE: To analyse the discrepancy between the karyotype in direct preparations of chorionic villus sampling (CVS) and the fetal karyotype and its possible fetal phenotypic repercussion. METHODS: The karyotype was obtained from direct and cultured preparations of CVS. FISH was performed in direct CVS preparations and in four different areas of term placenta. RESULTS: Karyotype and FISH analysis in CVS revealed a 46,XX/47,XX,+i(11q) cell line. Cultured CVS preparations showed a 46,XX karyotype. Cytogenetic studies in term placenta did not reveal the abnormal cell line. Molecular studies did not detect uniparental disomy for chromosome 11 in the fetus. CONCLUSION: The fetus, at birth, had no phenotypic abnormalities. IUGR was not present during gestation, in accordance with the low proportion of aneuploid cells in term placenta, and UPD for chromosome 11 was not observed.