Case Report: Androgenetic/biparental chimera with two biparental cell lines leading to placental mesenchymal dysplasia: a possible novel mechanism of formation.

Placental mesenchymal dysplasia (PMD) is a rare placental pathology that may be associated with Beckwith-Wiedemann features in the fetus and may be due to the presence of an androgenetic cell line. Many of the reported PMD cases describe the presence of a biparental and an isodisomic androgenetic cell line. The proposed mechanism of formation is by fertilization of a haploid ovum by a haploid sperm and duplication of the male pronucleus.

Comprehensive Clinical and Genetic Characterization of a Spanish Cohort of 22 Patients With Bainbridge-Ropers Syndrome.

Bainbridge-Ropers Syndrome (BRPS) is a genetic condition resulting from truncating variants in the ASXL3 gene. The clinical features include neurodevelopmental and language impairments, behavioral issues, hypotonia, feeding difficulties, and distinctive facial features. In this retrospective study, we analyzed 22 Spanish individuals with BRPS, aiming to perform a detailed clinical and molecular description and establish a genotype-phenotype correlation.

Spectrum disorder of RFC1 expansions/CANVAS: Clinical and electrophysiological characterization of a group of 31 patients.

Introduction/objective: Biallelic expansion of the pentanucleotide AAGGG in the RFC1- gene is associated with cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS). This study aimed to comprehensively characterise this condition by conducting an in-depth neurophysiological examination of afflicted patients.

Methods: A retrospective analysis was conducted in 31 RFC1-positive patients.

Patients with Thyroid Dyshormonogenesis and Variants: Molecular and Clinical Description and Genotype-Phenotype Correlation.

Thyroid dyshormonogenesis (THD) is a heterogeneous group of genetic diseases caused by the total or partial defect in the synthesis or secretion of thyroid hormones. Genetic variants in can cause partial to total iodination organification defects and clinical heterogeneity, from transient to permanent congenital hypothyroidism. The aim of this study was to undertake a molecular characterization and genotype-phenotype correlation in patients with THD and candidate variants in .

Performance of Massive Parallel Sequencing-Based Cell-Free DNA Testing in Compromised Pregnancies.

: Non-Invasive prenatal test (NIPT) is used as a universal or contingent test after prior risk assessment. Screening is mainly performed for common trisomies (T21, T13, T18), although other chromosomal anomalies may be detected. Our objective was to study the performance of GWNIPT in the detection of chromosomal abnormalities in pregnancies in which an invasive prenatal study was performed and in early pregnancy losses, in comparison with the reference test.

Clinical and molecular study of patients with thyroid dyshormogenesis and variants in the gene.

Introduction: Defects in any thyroid hormone synthesis steps cause thyroid dyshormonogenesis (THD). THD due to () gene variants is a cause of congenital hypothyroidism (CH) with a wide clinical spectrum, ranging from mild to severe permanent hypothyroidism. We present high-throughput sequencing results of patients with variants.

Clinical and Genetic Analysis of Patients With TK2 Deficiency.

Objectives: Thymidine kinase 2 deficiency (TK2d) is a rare autosomal recessive disorder that stems from a perturbation of the mitochondrial DNA maintenance. Nucleoside treatment has recently shown promise as a disease-modifying therapy. TK2d was initially associated with rapidly progressive fatal myopathy in children featuring mitochondrial DNA depletion.

Genetics and Natural History of Non-pancreatectomized Patients With Congenital Hyperinsulinism Due to Variants in ABCC8.

Context: Patients with congenital hyperinsulinism due to ABCC8 variants generally present severe hypoglycemia and those who do not respond to medical treatment typically undergo pancreatectomy. Few data exist on the natural history of non-pancreatectomized patients.

Objective: This work aims to describe the genetic characteristics and natural history in a cohort of non-pancreatectomized patients with congenital hyperinsulinism due to variants in the ABCC8 gene.

Limb-girdle myopathy and mild intellectual disability: The expanding spectrum of TANGO2-related disease.

TANGO2-related disease is an autosomal recessive multisystem disease associated with developmental delay and infancy-onset recurrent metabolic crises with early mortality. Several studies have reported dysfunction in endoplasmic reticulum-to-Golgi traffic and mitochondrial homoeostasis as the underlying pathophysiology. We report a 40-year-old woman affected by limb-girdle weakness and mild intellectual disability caused by the recurrent deletion of exons 3-9 in homozygosity in the TANGO2 gene.

Identification of two novel RRM2B variants associated with autosomal recessive progressive external ophthalmoplegia in a family with pseudodominant inheritance pattern.

RRM2B encodes the p53-inducible small subunit (p53R2) of ribonucleotide reductase, a key protein for mitochondrial DNA (mtDNA) synthesis. Pathogenic variants in this gene result in familial mitochondrial disease in adults and children, secondary to a maintenance disorder of mtDNA. This study describes two patients, mother and son, with early-onset chronic progressive external ophthalmoplegia (PEO).

Experience using singleton exome sequencing of probands as an approach to preconception carrier screening in consanguineous couples.

Background: Consanguineous couples have an increased risk of severe diseases in offspring due to autosomal recessive disorders. Exome sequencing (ES) offers the possibility of extensive preconception carrier screening (PCS) in consanguineous couples who may be at risk of rare genetic disorders.

Methods: We retrospectively analysed ES data from 65 probands affected with rare genetic disorders born from consanguineous couples.

An spanish study of secondary findings in families affected with mendelian disorders: choices, prevalence and family history.

Clinical exome sequencing has the potential to identify pathogenic variants unrelated to the purpose of the study (secondary findings, SFs). Data describing actual choices of SFs in participants in a clinical setting and factors influencing their decision are virtually non-existant in Europe. In this work, we report the acceptance rate of SFs, calculate their prevalence and study factors associated with the decision in a cohort of patients affected with a rare genetic disorder in a Spanish Hospital.

Clinical and psychological implications of secondary and incidental findings in cancer susceptibility genes after exome sequencing in patients with rare disorders.

Background/objectives: Exome sequencing may identify pathogenic variants unrelated with the purpose of the analysis. We investigated the frequency of secondary and incidental findings (SF/IF) in cancer susceptibility genes (CSG), their clinical actionability and the psychological impact in individuals with an SF/IF (cases) compared with individuals tested due to their cancer history (controls).

Methods: This study analysed 533 exomes ordered for non-cancer conditions.

A method for multiplexed full-length single-molecule sequencing of the human mitochondrial genome.

Methods to reconstruct the mitochondrial DNA (mtDNA) sequence using short-read sequencing come with an inherent bias due to amplification and mapping. They can fail to determine the phase of variants, to capture multiple deletions and to cover the mitochondrial genome evenly. Here we describe a method to target, multiplex and sequence at high coverage full-length human mitochondrial genomes as native single-molecules, utilizing the RNA-guided DNA endonuclease Cas9.

An Atypical Presentation of Upper Motor Neuron Predominant Juvenile Amyotrophic Lateral Sclerosis Associated with Gene: A Case Report and Review of the Literature.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that can rarely affect young individuals. Juvenile ALS (JALS) is defined for individuals with an onset of the disease before the age of 25. The contribution of genetics to ALS pathology is a field of growing interest.

Multicentric Standardization of Protocols for the Diagnosis of Human Mitochondrial Respiratory Chain Defects.

The quantification of mitochondrial respiratory chain (MRC) enzymatic activities is essential for diagnosis of a wide range of mitochondrial diseases, ranging from inherited defects to secondary dysfunctions. MRC lesion is frequently linked to extended cell damage through the generation of proton leak or oxidative stress, threatening organ viability and patient health. However, the intrinsic challenge of a methodological setup and the high variability in measuring MRC enzymatic activities represents a major obstacle for comparative analysis amongst institutions.