Clinical spectrum of rare bone fragility disorders and response to bisphosphonate treatment: a retrospective study.

Osteogenesis Imperfecta (OI) is a clinically and genetically heterogeneous group of diseases characterized by brittle bones. Though genetic mutations in COL1A1 and COL1A2 account for approximately 85-90% of OI cases, there are now more than twenty genes described, responsible for rare forms of OI. Treatment is based on the use of bisphosphonates and though it is well established that they increase lumbar spine (LS) bone mineral density (BMD), the clinical impact on fracture reduction is still debated.

PGT and deferred embryo transfer: Is blastocyst biopsy more effective than cleaved embryo biopsy?

Objective: Blastocyst biopsy has recently been implemented in our laboratory for PGT with a "freeze all" indication. The aim of this study is to compare PGT results between embryos biopsied at the cleaved and embryos biopsied at the blastocyst stage.

Study Design: This is a retrospective cohort study conducted from January 2017 to December 2022 in France.

Preimplantation genetic testing for mitochondrial DNA mutation: ovarian response to stimulation, outcomes and follow-up.

Research Question: How do carriers of pathogenic mitochondrial DNA (mtDNA) respond to ovarian stimulation?

Design: A single-centre, retrospective study conducted between January 2006 and July 2021 in France. Ovarian reserve markers and ovarian stimulation cycle outcomes were compared for couples undergoing preimplantation genetic testing (PGT) for maternally inherited mtDNA disease (n = 18) (mtDNA-PGT group) with a matched-control group of patients undergoing PGT for male indications (n = 96). The PGT outcomes for the mtDNA-PGT group and the follow-up of these patients in case of unsuccessful PGT was also reported.

A retrospective study on the efficacy of prenatal diagnosis for pregnancies at risk of mitochondrial DNA disorders.

Purpose: Prenatal diagnosis of mitochondrial DNA (mtDNA) disorders is challenging due to potential instability of fetal mutant loads and paucity of data connecting prenatal mutant loads to postnatal observations. Retrospective study of our prenatal cohort aims to examine the efficacy of prenatal diagnosis to improve counseling and reproductive options for those with pregnancies at risk of mtDNA disorders.

Methods: We report on a retrospective review of 20 years of prenatal diagnosis of pathogenic mtDNA variants in 80 pregnant women and 120 fetuses.

Homozygous Loss-of-Function Mutations in CCDC134 Are Responsible for a Severe Form of Osteogenesis Imperfecta.

Osteogenesis imperfecta (OI) is a primary bone fragility disorder with an estimated prevalence of 1 in 15,000 births. The majority of OI cases are inherited in an autosomal-dominant manner, while 5% to 10% have recessive or X-linked inheritance. Up to now, approximately 5% of OI cases remain without mutation demonstrated, supporting the involvement of other genes in the disease spectrum.

CTG Expansion in the DMPK Gene: Semen Quality Assessment and Outcome of Preimplantation Genetic Diagnosis.

Context: Myotonic dystrophy (DM) is an autosomal dominant disorder characterized mainly by myotonia but also by primary hypogonadism. No study has reported on fertility management of patients affected by DM type 1 (DM1).

Objective: This study investigates the impact of CTG repeats in the DMPK gene on semen quality and preimplantation genetic diagnosis (PGD) outcome.

Pycnodysostosis: Natural history and management guidelines from 27 French cases and a literature review.

Pycnodysostosis is a lysosomal autosomal recessive skeletal dysplasia characterized by osteosclerosis, short stature, acro-osteolysis, facial features and an increased risk of fractures. The clinical heterogeneity of the disease and its rarity make it difficult to provide patients an accurate prognosis, as well as appropriate care and follow-up. French physicians from the OSCAR network have been asked to fill out questionnaires collecting molecular and clinical data for 27 patients issued from 17 unrelated families.

mutations are responsible for autosomal recessive osteogenesis imperfecta.

Background: Stüve-Wiedemann syndrome (SWS) is characterised by bowing of the lower limbs, respiratory distress and hyperthermia that are often responsible for early death. Survivors develop progressive scoliosis and spontaneous fractures. We previously identified mutations in most SWS cases, but absence of pathogenic changes in five patients led us to perform exome sequencing and to identify homozygosity for a mutation in one case [p.

Segregation of mitochondrial DNA mutations in the human placenta: implication for prenatal diagnosis of mtDNA disorders.

Background: Mitochondrial DNA (mtDNA) disorders have a high clinical variability, mainly explained by variation of the mutant load across tissues. The high recurrence risk of these serious diseases commonly results in requests from at-risk couples for prenatal diagnosis (PND), based on determination of the mutant load on a chorionic villous sample (CVS). Such procedures are hampered by the lack of data regarding mtDNA segregation in the placenta.

Molecular diagnosis of hypophosphatasia and differential diagnosis by targeted Next Generation Sequencing.

Hypophosphatasia (HPP) is a rare inherited skeletal dysplasia due to loss of function mutations in the ALPL gene. The disease is subject to an extremely high clinical heterogeneity ranging from a perinatal lethal form to odontohypophosphatasia affecting only teeth. Up to now genetic diagnosis of HPP is performed by sequencing the ALPL gene by Sanger methodology.

Parental mosaicism is a pitfall in preimplantation genetic diagnosis of dominant disorders.

PCR amplification on single cells is prone to allele drop-out (PCR failure of one allele), a cause of misdiagnosis in preimplantation genetic diagnosis (PGD). Owing to this error risk, PGD usually relies on both direct and indirect genetic analyses. When the affected partner is the sporadic case of a dominant disorder, building haplotypes require spermatozoon or polar body testing prior to PGD, but these procedures are cost and time-consuming.

Mutations in KLHL40 are a frequent cause of severe autosomal-recessive nemaline myopathy.

Nemaline myopathy (NEM) is a common congenital myopathy. At the very severe end of the NEM clinical spectrum are genetically unresolved cases of autosomal-recessive fetal akinesia sequence. We studied a multinational cohort of 143 severe-NEM-affected families lacking genetic diagnosis.

Mutation dependance of the mitochondrial DNA copy number in the first stages of human embryogenesis.

Mitochondrial DNA (mtDNA) content is thought to remain stable over the preimplantation period of human embryogenesis that is, therefore, suggested to be entirely dependent on ooplasm mtDNA capital. We have explored the impact of two disease-causing mutations [m.3243A>G myopathy, encephalopathy, lactic acidosis and stroke-like syndrome (MELAS) and m.

Identification of mutations in TMEM5 and ISPD as a cause of severe cobblestone lissencephaly.

Cobblestone lissencephaly is a peculiar brain malformation with characteristic radiological anomalies. It is defined as cortical dysplasia that results when neuroglial overmigration into the arachnoid space forms an extracortical layer that produces agyria and/or a "cobblestone" brain surface and ventricular enlargement. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal-recessive diseases characterized by cerebral, ocular, and muscular deficits.

Poor correlations in the levels of pathogenic mitochondrial DNA mutations in polar bodies versus oocytes and blastomeres in humans.

Because the mtDNA amount remains stable in the early embryo until uterine implantation, early human development is completely dependent on the mtDNA pool of the mature oocyte. Both quantitative and qualitative mtDNA defects therefore may negatively impact oocyte competence or early embryonic development. However, nothing is known about segregation of mutant and wild-type mtDNA molecules during human meiosis.

Segregation of mtDNA throughout human embryofetal development: m.3243A>G as a model system.

Mitochondrial DNA (mtDNA) mutations cause a wide range of serious diseases with high transmission risk and maternal inheritance. Tissue heterogeneity of the heteroplasmy rate ("mutant load") accounts for the wide phenotypic spectrum observed in carriers. Owing to the absence of therapy, couples at risk to transmit such disorders commonly ask for prenatal (PND) or preimplantation diagnosis (PGD).

Structural insights on pathogenic effects of novel mutations causing pyruvate carboxylase deficiency.

Pyruvate carboxylase (PC), a key enzyme for gluconeogenesis and anaplerotic pathways, consists of four domains, namely, biotin carboxylase (BC), carboxyltransferase (CT), pyruvate carboxylase tetramerization (PT), and biotin carboxyl carrier protein (BCCP). PC deficiency is a rare metabolic disorder inherited in an autosomal recessive way. The most severe form (form B) is characterized by neonatal lethal lactic acidosis, whereas patients with form A suffer chronic lactic acidosis with psychomotor retardation.

Partial Xp11.23-p11.4 duplication with random X inactivation: clinical report and molecular cytogenetic characterization.

Partial duplications of the short arm of the X chromosome are relatively rare and have been described in males and females. We describe a 4 10/12-year-old girl presenting with developmental delay, severe language retardation and minor anomalies with slightly elevated head circumference (+1.8 SD), prominent forehead, wide palpebral fissures and anteverted nares.

Wolfram syndrome in French population: characterization of novel mutations and polymorphisms in the WFS1 gene.

Wolfram syndrome (WS), a rare autosomal recessive neurodegenerative disorder, results in most cases from mutations in the WFS1 gene. In this study, a total of 19 patients with Wolfram syndrome and 36 relatives from 17 families were screened for mutations in the WFS1 gene. WFS1 mutations were identified on both alleles in 16 of 19 patients and on 1 allele of 3 patients, showing that WFS1 is the major gene involved in WS in the french population.