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.

Clinical description, molecular delineation and genotype-phenotype correlation in 340 patients with KBG syndrome: addition of 67 new patients.

Background: KBG syndrome is a highly variable neurodevelopmental disorder and clinical diagnostic criteria have changed as new patients have been reported. Both loss-of-function sequence variants and large deletions (copy number variations, CNVs) involving cause KBG syndrome, but no genotype-phenotype correlation has been reported.

Methods: 67 patients with KBG syndrome were assessed using a custom phenotypical questionnaire.

Novel Gene Mutations in a Boy with Crigler-Najjar Syndrome Type II.

In this article, we reported a patient with Crigler-Najjar syndrome type II with high-unconjugated bilirubin levels that decreased after phenobarbital treatment. The patient had two novel missense mutations in the gene and a promoter variant in one allele. One mutation was c.

A Comprehensive Analysis of Choroideremia: From Genetic Characterization to Clinical Practice.

Choroideremia (CHM) is a rare X-linked disease leading to progressive retinal degeneration resulting in blindness. The disorder is caused by mutations in the CHM gene encoding REP-1 protein, an essential component of the Rab geranylgeranyltransferase (GGTase) complex. In the present study, we evaluated a multi-technique analysis algorithm to describe the mutational spectrum identified in a large cohort of cases and further correlate CHM variants with phenotypic characteristics and biochemical defects of choroideremia patients.

Dominant Retinitis Pigmentosa, p.Gly56Arg Mutation in NR2E3: Phenotype in a Large Cohort of 24 Cases.

Importance: This research is the single largest NR2E3 genotype-phenotype correlation study performed to date in autosomal dominant Retinitis Pigmentosa.

Objective: The aim of this study is to analyse the frequency of the p.Gly56Arg mutation in NR2E3 for the largest cohort of autosomal dominant Retinitis Pigmentosa patients to date and its associated phenotype.

Genotyping microarray: mutation screening in Spanish families with autosomal dominant retinitis pigmentosa.

Purpose: Presently, 22 genes have been described in association with autosomal dominant retinitis pigmentosa (adRP); however, they explain only 50% of all cases, making genetic diagnosis of this disease difficult and costly. The aim of this study was to evaluate a specific genotyping microarray for its application to the molecular diagnosis of adRP in Spanish patients.

Methods: We analyzed 139 unrelated Spanish families with adRP.

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).

A PTG variant contributes to a milder phenotype in Lafora disease.

Lafora disease is an autosomal recessive form of progressive myoclonus epilepsy with no effective therapy. Although the outcome is always unfavorable, onset of symptoms and progression of the disease may vary. We aimed to identify modifier genes that may contribute to the clinical course of Lafora disease patients with EPM2A or EPM2B mutations.

Mutation analysis at codon 838 of the Guanylate Cyclase 2D gene in Spanish families with autosomal dominant cone, cone-rod, and macular dystrophies.

Purpose: Heterozygous mutations around codon 838 of the guanylate cyclase 2D (GUCY2D) gene have recently been associated with more than a third of autosomal dominant macular dystrophy patients. The aim of our study was to evaluate the prevalence of these mutations in Spanish families with autosomal dominant cone, cone-rod, and macular dystrophies.

Methods: Mutation analysis was performed by PCR amplification of exon 13 of GUCY2D and subsequent restriction analysis.

[Holt-Oram syndrome: study of 7 cases].

Unlabelled: FUNDAMENTAL AND OBJECTIVE: Holt-Oram syndrome (HOS) is a heart-hand disease with an autosomal dominant inheritance pattern. About 85% of the affected patients present de novo mutations in the TBX5 gene. The aim of this study is to propose a molecular strategy to diagnose patients with clinical suspicion of HOS.

Comparison of high-resolution melting analysis with denaturing high-performance liquid chromatography for mutation scanning in the ABCA4 gene.

Purpose: Mutations in the ABCA4 gene have been associated with autosomal recessive Stargardt disease (STGD), a few cases of autosomal recessive cone-rod dystrophy (arCRD), and autosomal recessive retinitis pigmentosa (arRP). The purpose of this study was to compare high-resolution melting (HRM) analysis with denaturing high-performance liquid chromatography (dHPLC), to evaluate the efficiency of the different screening methodologies.

Methods: Thirty-eight STGD, 15 arCRD, and 5 arRP unrelated Spanish patients who had been analyzed with the ABCR microarray were evaluated.

Correlation of genetic and clinical findings in Spanish patients with X-linked juvenile retinoschisis.

Purpose: X-linked juvenile retinoschisis (XLRS) is one of the most common causes of juvenile macular degeneration in males, characterized by microcystic changes, splitting within the inner retinal layer (schisis), and the presence of vitreous veils. This study was conducted to describe and further correlate specific genetic variation in Spanish patients with XLRS with clinical characteristics and additional ophthalmic complications.

Methods: The study was performed in 34 Spanish families with XLRS, comprising 51 affected males.

Improvement in strategies for the non-invasive prenatal diagnosis of Huntington disease.

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.

Serotype-dependent packaging of large genes in adeno-associated viral vectors results in effective gene delivery in mice.

Vectors derived from adeno-associated virus (AAV) are promising for human gene therapy, including treatment for retinal blindness. One major limitation of AAVs as vectors is that AAV cargo capacity has been considered to be restricted to 4.7 kb.

New type of mutations in three spanish families with choroideremia.

Purpose: Choroideremia (CHM) is an X-linked ophthalmic disease. The gene associated with CHM (REP-1) encodes a ubiquitously expressed protein that is indispensable for the posttranslational activation of retina-specific Rab protein. Different mutations, including large genomic rearrangements involving the REP-1 gene, are responsible for CHM, but they all cause the protein to be truncated or absent.

Novel adeno-associated virus serotypes efficiently transduce murine photoreceptors.

Severe inherited retinal diseases, such as retinitis pigmentosa and Leber congenital amaurosis, are caused by mutations in genes preferentially expressed in photoreceptors. While adeno-associated virus (AAV)-mediated gene transfer can correct retinal pigment epithelium (RPE) defects in animal models, approaches for the correction of photoreceptor-specific diseases are less efficient. We evaluated the ability of novel AAV serotypes (AAV2/7, AAV2/8, AAV2/9, AAV2rh.

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.

Mutational screening of the RP2 and RPGR genes in Spanish families with X-linked retinitis pigmentosa.

Purpose: The X-linked form of retinitis pigmentosa (XLRP) is the most severe type because of its early onset and rapid progression. Five XLRP loci have been mapped, although only two genes, RPGR (for RP3) and RP2, have been cloned. In this study, 30 unrelated XLRP Spanish families were screened to determine the molecular cause of the disease.

Double trisomy in spontaneous miscarriages: cytogenetic and molecular approach.

Background: Although single trisomy is the most common chromosomal abnormality observed within first trimester spontaneous abortions (SA) (>50%), double trisomy (DT) ranges from 0.21 to 2.8% in the literature.

Genotype-phenotype variations in five Spanish families with Norrie disease or X-linked FEVR.

Purpose: Norrie disease (OMIM 310600) is a rare X-linked disorder characterized by congenital blindness in males. Approximately 40 to 50% of the cases develop deafness and mental retardation. X-linked familial exudative vitreoretinopathy (XL-FEVR) is a hereditary ocular disorder characterized by a failure of peripheral retinal vascularization.

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.

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.