Guidelines for NGS procedures applied to prenatal diagnosis by the Spanish Society of Gynecology and Obstetrics and the Spanish Association of Prenatal Diagnosis.

OBJECTIVE: This document addresses the clinical application of next-generation sequencing (NGS) technologies for prenatal genetic diagnosis and aims to establish clinical practice recommendations in Spain to ensure uniformity in implementing these technologies into prenatal care. METHODS: A joint committee of expert obstetricians and geneticists was created to review the existing literature on fetal NGS for genetic diagnosis and to make recommendations for Spanish healthcare professionals. RESULTS: This guideline summarises technical aspects of NGS technologies, clinical indications in prenatal setting, considerations regarding findings to be reported, genetic counselling considerations as well as data storage and protection policies. CONCLUSIONS: This document provides updated recommendations for the use of NGS diagnostic tests in prenatal diagnosis. These recommendations should be periodically reviewed as our knowledge of the clinical utility of NGS technologies, applied during pregnancy, may advance.

A HOPEFUL ALTERNATIVE “THERAPY WITH INTRA- NASAL ESKETAMINE IN A PATIENT WITH RESISTANT DEPRESSION”. A CASE REPORT.

Major Depressive Disorder is the leading cause of disability worldwide. Treatment-resistant depression occurs in a subgroup of patients with this disorder, and consists of a lack of response to two or more different antidepressants under adequate doses and duration, with optimal adherence to treatment.

[Trimethylaminuria: three different mutations in a single family]. / Trimetilaminuria: tres mutaciones distintas en una sola familia.

INTRODUCTION: Background: primary trimethylaminuria or fish odor syndrome is a genetic metabolopathy characterized by the accumulation of trimethylamine, a very volatile compound in body secretions. Case report: we present the case of a healthy 8-month-old patient who, after the introduction of fish in the diet, starts a bad body odor that does not disappear with bathing. The mother visits the pediatrician repeatedly but no disorder is identified. The diagnosis is delayed until the patient is three years old. Due to maternal insistence, the patient is referred to our hospital unit, where genetic diagnostic tests are performed, enabling the paternal diagnosis that had gone unnoticed for 35 years and detecting three different mutations in the family. Discussion: primary trimethylaminuria is a genetic disease with specific symptomatology of bad body odor that can go unnoticed for many years. An adequate clinical suspicion and the request of adequate complementary tests allow its diagnosis and facilitate its clinical management.

INTRODUCCIÓN: Introducción: La trimetilaminuria primaria (TMAP) o síndrome de olor a pescado es una metabulopatía genética caracterizada por acumulo en secreciones corporales de un compuesto muy volátil, la trimetilamina.Caso clínico: paciente sana de 8 meses de edad que tras la introducción del pescado inicia mal olor corporal que no desaparece con el baño, la madre acude repetidamente al pediatra sin identificar el trastorno, el diagnóstico se retrasa hasta los 3 años de edad en que por insistencia materna, es derivada a nuestra Unidad Hospitalaria, realizándose pruebas genéticas diagnósticas y posibilitando el diagnostico paterno que había pasado desapercibido durante 35 años, detectándose 3 mutaciones distintas en la familia.Discusión: la trimetilaminuria primaria es una enfermedad de causa genética con sintomatología concreta de mal olor corporal que puede pasar desapercibida durante muchos años. Una sospecha clínica adecuada y la solicitud de pruebas complementarias, permite su diagnóstico y facilita su manejo clínico.

Early noninvasive prenatal detection of a fetal CRB1 mutation causing Leber congenital amaurosis.

PURPOSE: Leber congenital amaurosis (LCA) is one of the most severe inherited retinal dystrophies with the earliest age of onset. Mutations in the Crumbs homologue 1 (CRB1; OMIM 600105) gene explain 10%-24% of cases with LCA depending on the population. The aim of the present work was to study a fetal mutation associated to LCA in maternal plasma by a new methodology in the noninvasive prenatal diagnosis field: the denaturing High Performance Liquid Chromatography (dHPLC). METHODS: This study presents the case of a compound heterozygous fetus for two mutations in CRB1 (1q3.1-q32.2). dHPLC and automated DNA sequencing were used to detect the paternally inherited fetal mutation in a maternal plasma sample collected at the 12th week of gestation. To test the detection limit of dHPLC, we made serial dilutions of paternal DNA in control DNA. RESULTS: We were able to detect the presence of the paternally inherited fetal CRB1 mutation in maternal plasma by dHPLC. Moreover, by comparing chromatograms of serial dilutions to the plasma sample, we could ascertain that the percentage of fetal DNA in maternal plasma was at least 2%. However, the detection of the fetal mutation was not possible by automated DNA sequencing. CONCLUSIONS: dHPLC seems to be sensitive enough to detect small amounts of fetal DNA in maternal plasma samples. It could be a useful tool for the noninvasive prenatal detection of paternally inherited point mutations associated with retinopathies.

New strategy for the prenatal detection/exclusion of paternal cystic fibrosis mutations in maternal plasma.

BACKGROUND: Since the presence of fetal DNA was discovered in maternal blood, different investigations have focused on non-invasive prenatal diagnosis. The analysis of fetal DNA in maternal plasma may allow the diagnosis of fetuses at risk of cystic fibrosis (CF) without any risk of fetal loss. Here, we present a new strategy for the detection of fetal mutations causing CF in maternal plasma. METHODS: We have used a mini-sequencing based method, the SNaPshot, for fetal genotyping of the paternal mutation in maternal blood from three pregnancies at risk of CF. RESULTS: The paternal mutation was detected in the analysis of plasma samples from cases 1 and 3 but not in case 2. Results of a posterior conventional molecular analysis of chorionic biopsies were in full agreement with those obtained from analysis of the plasma samples. CONCLUSIONS: The knowledge about the inheritance of the paternal mutation in a fetus may avoid the conventional prenatal diagnosis in some cases. The SNaPshot technique has been shown to be a sensitive and accurate method for the detection of fetal mutations in maternal plasma. Its ease handling, rapid and low cost makes it appropriate for a future routine clinical use in non-invasive prenatal diagnosis of cystic fibrosis.

Detection of a paternally inherited fetal mutation in maternal plasma by the use of automated sequencing.

The discovery of circulating fetal DNA in maternal blood has been an encouraging step forward in the prenatal diagnostic field. It has opened up the possibility of development of a noninvasive method for the genetic analysis of the fetus. Many techniques have been applied to the study of this fetal DNA, but automated sequencing has been seldom used. The intention of this study was to use the automated sequencing technique for the detection of a paternally inherited fetal mutation in maternal plasma. Maternal plasma samples from a pregnant woman, whose husband had a mutation (Q134X) in the RP2 gene, which is located in the X-chromosome, were collected at two different gestational ages (10th and 19th week of gestation) in order to determine whether the paternally inherited fetal mutation could be detected by automated sequencing. Restriction analysis was also performed to confirm the results. The fetal mutation was clearly detected in the maternal plasma by the use of automated sequencing. The automated sequencing enables the possibility of analyzing fetal sequences, at a nucleotide level, in order to detect mutations or polymorphisms which are distinguishable from maternal sequences.

Application of fetal DNA detection in maternal plasma: a prenatal diagnosis unit experience.

Non-invasive prenatal diagnosis tests based on the analysis of fetal DNA in maternal plasma have potential to be a safer alternative to invasive methods. So far, different studies have shown mainly fetal sex, fetal RhD, and quantitative variations of fetal DNA during gestation with fetal chromosomal anomalies or gestations at risk for preeclampsia. The objective of our research was to evaluate the use of fetal DNA in maternal plasma for clinical application. In our study, we have established the methodology needed for the analysis of fetal DNA. Different methods were used, according to the requirements of the assay. We have used quantitative fluorescent polymerase chain reaction (QF-PCR) to perform fetal sex detection with 90% sensitivity. The same technique permitted the detection of fetal DNA from the 10th week of gestation to hours after delivery. We have successfully carried out the diagnosis of two inherited disorders, cystic fibrosis (conventional PCR and restriction analysis) and Huntington disease (QF-PCR). Ninety percent of the cases studied for fetal RhD by real-time PCR were correctly diagnosed. The detection of fetal DNA sequences is a reality and could reduce the risk of invasive techniques for certain fetal disorders in the near future.

Microdeletion found by array-CGH in girl with blepharophimosis syndrome and apparently balanced translocation t(3;15)(q23;q25).

BACKGROUND: Blepharophimosis, ptosis and epicanthus inversus syndrome (BPES) is a rare autosomal dominant congenital disorder. Mutations in FOXL2, a gene located at 3q23, have been shown to cause the syndrome. We report a girl with BPES with a "de novo" apparently balanced translocation between chromosomes 3 and 15: t(3;15)(q23;q25). MATERIAL AND METHODS: Conventional cytogenetic and CGH array were performed. RESULTS: The karyotype showed an apparently balanced translocation. Molecular studies by array-CGH did not show deletions in the FOXL2 gene; however, a novel 63.2 kb deletion involving a non-protein-coding gene (PISRT1) was found. CONCLUSIONS: The novel deletion found could be involved in FOXL2 regulation and constitutes the smallest deletion described in a female with BPES. In cases of "de novo" apparently balanced translocation, only a 5-6% risk of phenotype alteration is described. Molecular studies can help to discover these alterations and provide insight for genetic counseling.

Noninvasive prenatal diagnosis using ccffDNA in maternal blood: state of the art.

Owing to the risk of fetal loss associated with prenatal diagnostic procedures, the last decade has seen great developments in noninvasive prenatal diagnosis (NIPD). The discovery of circulating cell-free fetal DNA (ccffDNA) in maternal plasma has opened new lines of research in alternative technologies that may facilitate safe diagnosis. Because ccffDNA represents only a small fraction of all DNA present in maternal plasma and it is masked by the background of maternal DNA, the scope of NIPD was, until recently, limited to the study of paternal DNA sequences (i.e., detection of SRY sequences, RhD gene in RhD-negative women and paternally inherited single-gene disorders, such as cystic fibrosis and Huntington's disease). However, new discoveries and technology are making NIPD a real option for patients and providing for an array of clinical applications, such as molecular studies in high-risk families, general screening and pregnancy management.

Application of quantitative fluorescent PCR with short tandem repeat markers to the study of aneuploidies in spontaneous miscarriages.

BACKGROUND: Aneuploidies involve approximately 80% of chromosomal anomalies found in spontaneous miscarriages. Since cytogenetic studies show high rates of failure, we have incorporated the quantitative fluorescent polymerase chain reaction (QF-PCR) technique to the study of numerical chromosome anomalies in miscarriages. METHODS: Multiplex and simple QF-PCR assays have been performed on 160 miscarriage and 34 parental DNA samples analysing specific short tandem repeat (STR) markers for chromosomes 2, 7, 13, 15, 16, 18, 21, 22 and X. Cases successfully karyotyped were used as controls in our study. RESULTS: While maternal contamination could be detected in such cases, a molecular result was obtained for 94% of miscarriages without a cytogenetic one. Thirty-six per cent of them were diagnosed with numerical chromosome anomalies. Parental origin of the extra chromosome and the error stage of meiosis could be also determined. CONCLUSIONS: QF-PCR represents a useful and reliable tool to diagnose aneuploidies in spontaneous miscarriages. It provides information about parental and meiotic origin of anomaly, allowing an appropriate genetic counselling.

Turner phenotype in a girl with a 45,X/46,XX/47,XX,+18 mosaicism.

We report a girl with Turner syndrome phenotype, whose karyotype on amniocyte culture was 45,X, while cytogenetic analysis on peripheral blood lymphocytes showed the presence of a mosaic chromosome constitution with three different cell lines: 45,X[5]/46,XX[3]/47,XX,+18 [35]. No signs of trisomy 18 were observed and a follow up during childhood revealed normal psychomotor development. Parental origin and mechanism of formation were studied using high polymorphic microsatellites and Quantitative Fluorescent PCR. The 18-trisomic cells showed one paternal allele and two maternal homozygous alleles at different loci of chromosome 18, suggesting a maternal M-II meiotic or a postzygotic error. A biparental origin of the X-alleles in the trisomic cells were determined, being the paternal allele retained in the 45,X cells. The possible mechanism of formation implying meiotic and/or mitotic errors is discussed.

[Synchronic bilateral testicular seminomas. Ultrasound diagnosis]. / Seminomas testiculares bilaterales sincrónicos. Diagnóstico ecográfico.

OBJECTIVES: To report a new case of bilateral synchronic testicular tumors, and to perform a bibliographic review on the topic, emphasizing the ultrasound characteristics and oddity of these presentation, which accounts for less than 1% of germ cell testicular tumors. METHODS/RESULTS: 29-year-old patient consulting because of an increase of the testicular size over one year. Physical examination and ultrasound revealed a synchronic neoplastic involvement of the testicles, suggesting the radiological diagnosis of bilateral "seminomatous tumor", with "non seminomatous" foci in one of them. Histologically, tumors were in accordance with ultrasound working diagnosis (seminomas, showing one of them anaplastic foci). CONCLUSIONS: Synchronic testicular involvement by neoplasias is an unfrequent fact, scarcely reported in the literature, being most cases germ cell tumors, mainly seminomas, and shows a good correlation between ultrasound and histologic diagnosis.