Preclinical workup using long-read amplicon sequencing provides families with de novo pathogenic variants access to universal preimplantation genetic testing.

Study Question: Can long-read amplicon sequencing be beneficial for preclinical preimplantation genetic testing (PGT) workup in couples with a de novo pathogenic variant in one of the prospective parents?

Summary Answer: Long-read amplicon sequencing represents a simple, rapid and cost-effective preclinical PGT workup strategy that provides couples with de novo pathogenic variants access to universal genome-wide haplotyping-based PGT programs.

What Is Known Already: Universal PGT combines genome-wide haplotyping and copy number profiling to select embryos devoid of both familial pathogenic variants and aneuploidies. However, it cannot be directly applied in couples with a de novo pathogenic variant in one of the partners due to the absence of affected family members required for phasing the disease-associated haplotype.

Haplotyping-based preimplantation genetic testing reveals parent-of-origin specific mechanisms of aneuploidy formation.

Chromosome instability is inherent to human IVF embryos, but the full spectrum and developmental fate of chromosome anomalies remain uncharacterized. Using haplotyping-based preimplantation genetic testing for monogenic diseases (PGT-M), we mapped the parental and mechanistic origin of common and rare genomic abnormalities in 2300 cleavage stage and 361 trophectoderm biopsies. We show that while single whole chromosome aneuploidy arises due to chromosome-specific meiotic errors in the oocyte, segmental imbalances predominantly affect paternal chromosomes, implicating sperm DNA damage in segmental aneuploidy formation.

Two siblings with Heimler syndrome caused by PEX1 variants: follow-up of ophthalmologic findings.

Background: Heimler syndrome (OMIM number #234580 and #616617) is a rare condition comprising sensorineural hearing loss (SNHL), nail abnormalities and amelogenesis imperfecta. In addition, patients with this syndrome can have retinal dystrophies. Heimler syndrome is caused by bi-allelic pathogenic variants in the or gene.

Keratinocytic epidermal nevi associated with localized fibro-osseous lesions without hypophosphatemia.

Keratinocytic epidermal nevi (KEN) are characterized clinically by permanent hyperkeratosis in the distribution of Blaschko's lines and histologically by hyperplasia of epidermal keratinocytes. KEN with underlying RAS mutations have been associated with hypophosphatemic rickets and dysplastic bone lesions described as congenital cutaneous skeletal hypophosphatemia syndrome. Here, we describe two patients with keratinocytic epidermal nevi, in one associated with a papular nevus spilus, who presented with distinct localized congenital fibro-osseous lesions in the lower leg, diagnosed on both radiology and histology as osteofibrous dysplasia, in the absence of hypophosphatemia or rickets, or significantly raised FGF23 levels but with distinct mosaic HRAS mutations.

Cancer Surveillance in Healthy Carriers of Germline Pathogenic Variants in : A Review of Secondary Prevention Guidelines.

Germline pathogenic alterations in the breast cancer susceptibility genes 1 () and 2 () are the most prevalent causes of hereditary breast and ovarian cancer. The increasing trend in proportion of cancer patients undergoing genetic testing, followed by predictive testing in families of new index patients, results in a significant increase of healthy germline 2 mutation carriers who are at increased risk for breast, ovarian, and other -related cancers. This review aims to give an overview of available screening guidelines for female and male carriers of pathogenic or likely pathogenic germline variants per cancer type, incorporating malignancies that are more or less recently well correlated with .

Identity-by-state-based haplotyping expands the application of comprehensive preimplantation genetic testing.

Study Question: Is it possible to haplotype parents using parental siblings to leverage preimplantation genetic testing (PGT) for monogenic diseases and aneuploidy (comprehensive PGT) by genome-wide haplotyping?

Summary Answer: We imputed identity-by-state (IBS) sharing of parental siblings to phase parental genotypes.

What Is Known Already: Genome-wide haplotyping of preimplantation embryos is being implemented as a generic approach for genetic diagnosis of inherited single-gene disorders. To enable the phasing of genotypes into haplotypes, genotyping the direct family members of the prospective parent carrying the mutation is required.

Legius Syndrome and its Relationship with Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is the most common disorder characterized by multiple café-au-lait macules. Most individuals with this autosomal dominant disorder also have other features, such as skinfold freckling, iris Lisch nodules and benign or malignant peripheral nerve sheath tumours. Legius syndrome is a less frequent autosomal dominant disorder with similar multiple café-au-lait macules and skinfold freckling.

Next-generation sequencing in prenatal setting: Some examples of unexpected variant association.

The application of next-generation sequencing to fetal pathology has proved to increase the diagnostic yield in fetuses with abnormal ultrasounds. We retrospectively reviewed genetic data of 30 selected cases studied through targeted resequencing of OMIM genes. In our experience, clinical data proved to be essential to support diagnostic reasoning and enhance variants' assessment.

Genome-wide haplotyping embryos developing from 0PN and 1PN zygotes increases transferrable embryos in PGT-M.

Study Question: Can genome-wide haplotyping increase success following preimplantation genetic testing for a monogenic disorder (PGT-M) by including zygotes with absence of pronuclei (0PN) or the presence of only one pronucleus (1PN)?

Summary Answer: Genome-wide haplotyping 0PNs and 1PNs increases the number of PGT-M cycles reaching embryo transfer (ET) by 81% and the live-birth rate by 75%.

What Is Known Already: Although a significant subset of 0PN and 1PN zygotes can develop into balanced, diploid and developmentally competent embryos, they are usually discarded because parental diploidy detection is not part of the routine work-up of PGT-M.

Study Design, Size, Duration: This prospective cohort study evaluated the pronuclear number in 2229 zygotes from 2337 injected metaphase II (MII) oocytes in 268 cycles.

Expanding the clinical phenotype of individuals with a 3-bp in-frame deletion of the NF1 gene (c.2970_2972del): an update of genotype-phenotype correlation.

Purpose: Neurofibromatosis type 1 (NF1) is characterized by a highly variable clinical presentation, but almost all NF1-affected adults present with cutaneous and/or subcutaneous neurofibromas. Exceptions are individuals heterozygous for the NF1 in-frame deletion, c.2970_2972del (p.

NRAS Mutations in Noonan Syndrome.

Noonan syndrome is a genetically heterogeneous disorder caused by mutations in PTPN11, SOS1, RAF1 and less frequently in KRAS, NRAS or SHOC2. Here, we performed mutation analysis of NRAS and SHOC2 in 115 PTPN11, SOS1, RAF1, and KRAS mutation-negative individuals. No SHOC2 mutations were found, but we identified 3 NRAS mutations in 3 probands.

Multiple orbital neurofibromas, painful peripheral nerve tumors, distinctive face and marfanoid habitus: a new syndrome.

Four unrelated patients having an unusual clinical phenotype, including multiple peripheral nerve sheath tumors, are reported. Their clinical features were not typical of any known familial tumor syndrome. The patients had multiple painful neurofibromas, including bilateral orbital plexiform neurofibromas, and spinal as well as mucosal neurofibromas.

Observations on intelligence and behavior in 15 patients with Legius syndrome.

Legius syndrome is a RAS-MAPK syndrome characterized by pigmentary findings similar to neurofibromatosis type 1 (NF1), but without tumor complications. Learning difficulties and behavioral problems have been reported to be associated with Legius syndrome, but have not been studied systematically. We investigated intelligence and behavior in 15 patients with Legius syndrome and 7 unaffected family members.

Legius syndrome in fourteen families.

Legius syndrome presents as an autosomal dominant condition characterized by café-au-lait macules with or without freckling and sometimes a Noonan-like appearance and/or learning difficulties. It is caused by germline loss-of-function SPRED1 mutations and is a member of the RAS-MAPK pathway syndromes. Most mutations result in a truncated protein and only a few inactivating missense mutations have been reported.

Noonan syndrome and systemic lupus erythematosus in a patient with a novel KRAS mutation.

Noonan syndrome is characterised by distinct facial stigmata, short stature and congenital cardiopathy. It has a high genetic heterogeneity and mutations in six different genes can be involved. We report a patient with Noonan syndrome and a novel KRAS mutation who presents systemic lupus erythematosus.

Investigation of gene dosage imbalances in patients with Noonan syndrome using multiplex ligation-dependent probe amplification analysis.

The RAS-MAPK syndromes are a group of clinically and genetically related disorders caused by dysregulation of the RAS-MAPK pathway. A member of this group of disorders, Noonan syndrome (NS), is associated with several different genes within the RAS-MAPK pathway. To date, mutations in PTPN11, SOS1, KRAS, RAF1 and SHOC2 are known to cause NS and a small group of patients harbour mutations in BRAF, MEK1 or NRAS.

Tumor spectrum in children with Noonan syndrome and SOS1 or RAF1 mutations.

Noonan syndrome (NS) is an autosomal dominant disorder caused by mutations in PTPN11, KRAS, SOS1, and RAF1. We performed SOS1, RAF1, BRAF, MEK1, and MEK2 mutation analysis in a cohort of 102 PTPN11- and KRAS-negative NS patients and found pathogenic SOS1 mutations in 10, RAF1 mutations in 4, and BRAF mutations in 2 patients. Three novel SOS1 mutations were found.

Clinical and mutational spectrum of neurofibromatosis type 1-like syndrome.

Context: Autosomal dominant inactivating sprouty-related EVH1 domain-containing protein 1 (SPRED1) mutations have recently been described in individuals presenting mainly with café au lait macules (CALMs), axillary freckling, and macrocephaly. The extent of the clinical spectrum of this new disorder needs further delineation.

Objective: To determine the frequency, mutational spectrum, and phenotype of neurofibromatosis type 1-like syndrome (NFLS) in a large cohort of patients.

Pathogenesis of vestibular schwannoma in ring chromosome 22.

Background: Ring chromosome 22 is a rare human constitutional cytogenetic abnormality. Clinical features of neurofibromatosis type 1 and 2 as well as different tumour types have been reported in patients with ring chromosome 22. The pathogenesis of these tumours is not always clear yet.

A preliminary report on the efficacy of the Multicare AR-Bed in 3-week-3-month-old infants on regurgitation, associated symptoms and acid reflux.

Objectives: The aim of this preliminary study was to evaluate the efficacy of a 40 degrees supine body position on infant regurgitation, reflux-associated symptoms and acid reflux.

Intervention: Thirty of 52 consecutive infants presenting with frequent regurgitation and reflux-associated symptoms occurring mainly during feeding were evaluated in the Multicare AR-Bed (Peos, Ninove, Belgium). The Infant-Gastroesophageal Reflux Questionnaire-Revised (I-GERQ-R) and an oesophageal pH monitoring were performed at inclusion and after 1 week.

Spred1 is required for synaptic plasticity and hippocampus-dependent learning.

Germline mutations in SPRED1, a negative regulator of Ras, have been described in a neurofibromatosis type 1 (NF1)-like syndrome (NFLS) that included learning difficulties in some affected individuals. NFLS belongs to the group of phenotypically overlapping neuro-cardio-facial-cutaneous syndromes that are all caused by germ line mutations in genes of the Ras/mitogen-activated protein kinase extracellular signal-regulated kinase (ERK) pathway and that present with some degree of learning difficulties or mental retardation. We investigated hippocampus-dependent learning and memory as well as synaptic plasticity in Spred1(-/-) mice, an animal model of this newly discovered human syndrome.

Osteopathy may decrease obstructive apnea in infants: a pilot study.

Background: Obstructive apnea is a sleep disorder characterized by pauses in breathing during sleep: breathing is interrupted by a physical block to airflow despite effort. The purpose of this study was to test if osteopathy could influence the incidence of obstructive apnea during sleep in infants.

Methods: Thirty-four healthy infants (age: 1.