A novel RAB39B mutation and concurrent de novo NF1 mutation in a boy with neurofibromatosis type 1, intellectual disability, and autism: a case report.

Background: Mutations in RAB39B at Xq28 causes a rare form of X-linked intellectual disability (ID) and Parkinson's disease. Neurofibromatosis type 1 (NF1) is caused by heterozygous mutations in NF1 occurring de novo in about 50% of cases, usually due to paternal gonadal mutations. This case report describes clinical and genetic findings in a boy with the occurrence of two distinct causative mutations in NF1 and RAB39B explaining the observed phenotype.

The position of nonsense mutations can predict the phenotype severity: A survey on the DMD gene.

A nonsense mutation adds a premature stop signal that hinders any further translation of a protein-coding gene, usually resulting in a null allele. To investigate the possible exceptions, we used the DMD gene as an ideal model. First, because dystrophin absence causes Duchenne muscular dystrophy (DMD), while its reduction causes Becker muscular dystrophy (BMD).

Identification and Characterization of Splicing Defects by Single-Molecule Real-Time Sequencing Technology (PacBio).

Although DNA-sequencing is the most effective procedure to achieve a molecular diagnosis in genetic diseases, complementary RNA analyses are often required.Reverse-Transcription polymerase chain reaction (RT-PCR) is still a valuable option when the clinical phenotype and/or available DNA-test results address the diagnosis toward a gene of interest or when the splicing effect of a single variant needs to be assessed.We use Single-Molecule Real-Time sequencing to detect and characterize splicing defects and single nucleotide variants in well-known disease genes (DMD, NF1, TTN).

Improved Criteria for the Classification of Titin Variants in Inherited Skeletal Myopathies.

Background: Extensive genetic screening results in the identification of thousands of rare variants that are difficult to interpret. Because of its sheer size, rare variants in the titin gene (TTN) are detected frequently in any individual. Unambiguous interpretation of molecular findings is almost impossible in many patients with myopathies or cardiomyopathies.

Improving Copy Number Variant Detection from Sequencing Data with a Combination of Programs and a Predictive Model.

Bioinformatics tools for analyzing copy number variants (CNVs) from massively parallel sequencing (MPS) data are less well developed compared with other variant types. We present an efficient bioinformatics pipeline for CNV detection from gene panel MPS data in neuromuscular disorders. CNVs were generated in silico into samples sequenced with a previously published MPS gene panel.

Clinical and Genetic Findings in Children with Neurofibromatosis Type 1, Legius Syndrome, and Other Related Neurocutaneous Disorders.

Pigmentary manifestations can represent an early clinical sign in children affected by Neurofibromatosis type 1 (NF1), Legius syndrome, and other neurocutaneous disorders. The differential molecular diagnosis of these pathologies is a challenge that can now be met by combining next generation sequencing of target genes with concurrent second-level tests, such as multiplex ligation-dependent probe amplification and RNA analysis. We clinically and genetically investigated 281 patients, almost all pediatric cases, presenting with either NF1 ( = 150), only pigmentary features (café au lait macules with or without freckling; ( = 95), or clinical suspicion of other RASopathies or neurocutaneous disorders ( = 36).

Congenital myopathy with hanging big toe due to homozygous myopalladin (MYPN) mutation.

Background: Myopalladin (MYPN) is a component of the sarcomere that tethers nebulin in skeletal muscle and nebulette in cardiac muscle to alpha-actinin at the Z lines. Autosomal dominant MYPN mutations cause hypertrophic, dilated, or restrictive cardiomyopathy. Autosomal recessive MYPN mutations have been reported in only six families showing a mildly progressive nemaline or cap myopathy with cardiomyopathy in some patients.

A Novel 12q13.2-q13.3 Microdeletion Syndrome With Combined Features of Diamond Blackfan Anemia, Pierre Robin Sequence and Klippel Feil Deformity.

Diamond-Blackfan anemia (DBA) is a rare congenital erythroid aplasia with a highly heterogeneous genetic background; it usually occurs in infancy. Approximately 30-40% of patients have other associated congenital anomalies; in particular, facial anomalies, such as cleft palate, are part of about 10% of the DBA clinical presentations. Pierre Robin sequence (PRS) is a heterogeneous condition, defined by the presence of the triad of glossoptosis, micrognathia and cleft palate; it occurs in 1/8500 to 1/14,000 births.

Copy Number Variants Account for a Tiny Fraction of Undiagnosed Myopathic Patients.

Next-generation sequencing (NGS) technologies have led to an increase in the diagnosis of heterogeneous genetic conditions. However, over 50% of patients with a genetically inherited disease are still without a diagnosis. In these cases, different hypotheses are usually postulated, including variants in novel genes or elusive mutations.

Whole exome sequencing identifies MRVI1 as a susceptibility gene for moyamoya syndrome in neurofibromatosis type 1.

Background And Purpose: Moyamoya angiopathy is a progressive cerebral vasculopathy. The p.R4810K substitution in RNF213 has previously been linked to moyamoya disease in Asian populations.

Seizures in children with neurofibromatosis type 1: is neurofibromatosis type 1 enough?

Background: Neurofibromatosis type 1 (NF1) is related to a generally increased prevalence of seizures. The mechanism underlying the increased predisposition to seizures has not been fully elucidated. The aim of the study was to evaluate the role of NF1 in seizures pathogenesis in a cohort of children with NF1 and seizures.

Interpreting Genetic Variants in Titin in Patients With Muscle Disorders.

Importance: Mutations in the titin gene (TTN) cause a wide spectrum of genetic diseases. The interpretation of the numerous rare variants identified in TTN is a difficult challenge given its large size.

Objective: To identify genetic variants in titin in a cohort of patients with muscle disorders.

UBE2A deficiency in two siblings: A novel splicing variant inherited from a maternal germline mosaicism.

UBE2A deficiency is a syndromic condition of X-linked intellectual disability (ID) characterized by typical dysmorphic features that include synophrys, prominent supraorbital ridges, almond-shaped, and deep-set eyes, large ears, wide mouth, myxedematous appearance, hirsutism, micropenis, and onychodystrophy. To date, only seven familial UBE2A intragenic mutations and nine larger microdeletions encompassing UBE2A have been reported. Here, we describe two siblings with X-linked ID and typical clinical features of UBE2A deficiency caused by a novel hemizygous variant, identified by massively parallel sequencing of X-exome.

Assessment of de novo copy-number variations in Italian patients with schizophrenia: Detection of putative mutations involving regulatory enhancer elements.

Objectives: Variants appearing de novo in genes regulating key neurodevelopmental processes and/or in non-coding cis-regulatory elements (CREs), as enhancers, may increase the risk for schizophrenia. However, CREs involvement in schizophrenia needs to be explored more deeply.

Methods: We investigated de novo copy-number variations (CNVs) in the whole-genomic DNA obtained from 46 family trios of schizophrenia probands by using the Enhancer Chip, a customised array CGH able to investigate the whole genome with a 300-kb resolution, specific disease loci at a ten-fold higher resolution, and which was highly enriched in probes in more than 1,250 enhancer elements selected from Vista Enhancer Browser.

From Gardner fibroma diagnosis to constitutional mutation detection: a one-way street.

We report a young child without a family history of FAP, who promptly underwent testing after the histological confirmation of a paraspinal GAF that was not isolated. Our case report reinforces the suggestion advanced by previous authors for an analysis in all patients with GAF.

A novel SHANK3 interstitial microdeletion in a family with intellectual disability and brain MRI abnormalities resembling Unidentified Bright Objects.

Background: SHANK3 mutations are responsible for Phelan-McDermid syndrome but they are also associated with autism and/or intellectual disability.

Case Report: We report a family with four affected individuals including the 37 year-old mother, her 12 year-old male monozygotic twins and 8 year-old daughter harboring a novel SHANK3 interstitial microdeletion. All four members presented with intellectual disability of variable severity.

Moyamoya syndrome in children with neurofibromatosis type 1: Italian-French experience.

Moyamoya syndrome (MMS) is the most common cerebral vasculopathy among children with neurofibromatosis type 1 (NF1). In this study, we clinically, radiologically, and genetically examined a cohort that was not previously described, comprising European children with NF1 and MMS. The NF1 genotyping had been registered.

The genetic basis of undiagnosed muscular dystrophies and myopathies: Results from 504 patients.

Objective: To apply next-generation sequencing (NGS) for the investigation of the genetic basis of undiagnosed muscular dystrophies and myopathies in a very large cohort of patients.

Methods: We applied an NGS-based platform named MotorPlex to our diagnostic workflow to test muscle disease genes with a high sensitivity and specificity for small DNA variants. We analyzed 504 undiagnosed patients mostly referred as being affected by limb-girdle muscular dystrophy or congenital myopathy.

Identification of an intragenic deletion in the SGCB gene through a re-evaluation of negative next generation sequencing results.

A large mutation screening of 504 patients with muscular dystrophy or myopathy has been performed by next generation sequencing (NGS). Among this cohort of patients, we report a case with a severe form of muscular dystrophy with a proximal weakness in the limb-girdle muscles. Her biopsy revealed typical dystrophic features and immunohistochemistry for α- and γ-sarcoglycans showed an absent reaction, addressing the clinical diagnosis toward a sarcoglycanopathy.

New Mutations in NEB Gene Discovered by Targeted Next-Generation Sequencing in Nemaline Myopathy Italian Patients.

Nemaline myopathy represents a group of clinically and genetically heterogeneous neuromuscular disorders. Different clinical-genetic entities have been characterized in the last few years, with implications for diagnostics and genetic counseling. Fifty percent of nemaline myopathy forms are due to NEB mutations, but genetic analysis of this large and complex gene by Sanger sequencing is time consuming and expensive.

Novel findings associated with MTM1 suggest a higher number of female symptomatic carriers.

Mutations in the MTM1 gene cause X-linked myotubular myopathy (XLMTM), characterized by neonatal hypotonia and respiratory failure, and are responsible for a premature mortality in affected males. Female carriers are usually asymptomatic but they may present with muscular weakness because of a hypothesized skewed pattern of X-chromosome inactivation. By combining next generation sequencing (NGS) and CGH array approaches, we have investigated the role of MTM1 variants in a large cohort of undiagnosed patients with a wide spectrum of myopathies.