ABSTRACT
INTRODUCTION: Sprengel's deformity is a rare congenital anomaly of the shoulder rim. It is the most common congenital anomaly of the shoulder, associated with cosmetic deformity and abnormal shoulder function. Nonsurgical management can be considered for mild cases. Surgical intervention is indicated in moderate to severe cases with the goal of improving cosmetic appearance and function. The best surgical results are obtained in children aged 3-8 years. Correct diagnosis is very important because Sprengel's deformity can be accompanied by additional abnormalities, even in mild cases, and lack of a diagnosis delays proper treatment of the child. The severity of the defect may progress, so it is important to correctly identify children with Sprengel's deformity, even those with a mild form of the defect. CASE PRESENTATION: We report a case of prenatal sonographic diagnosis of Sprengel's deformity with additional features, as yet undescribed and missed - although visible - on prenatal magnetic resonance imaging (MRI). Cesarean delivery was performed due to preterm rupture of membranes, and a postnatal MRI confirmed the unusual constellation of Sprengel's anomaly with lateral meningocele, vestigial posterior meningocele, and lipoma tethering of the cord to the dural sac at the cervical-thoracic junction. CONCLUSION: Diagnosis of Sprengel's deformity is possible with prenatal ultrasound. Asymmetry of the cervical spine, discontinuity of the vertebral arch and abnormal vertebral bodies, as well as the asymmetric position of the shoulder blades with the presence of an omovertebral bone are signs that can help diagnose the defect.
Subject(s)
Congenital Abnormalities , Meningocele , Shoulder Joint , Child , Infant, Newborn , Female , Pregnancy , Humans , Scapula/abnormalities , Scapula/surgery , Shoulder Joint/diagnostic imaging , Shoulder Joint/surgery , Shoulder Joint/abnormalities , Magnetic Resonance Imaging , Congenital Abnormalities/diagnosisABSTRACT
Pseudouridine (Ψ) is an RNA base modification ubiquitously found in many types of RNAs. In humans, the isomerization of uridine is catalyzed by different stand-alone pseudouridine synthases (PUS). Genomic mutations in the human pseudouridine synthase 3 gene (PUS3) have been identified in patients with neurodevelopmental disorders. However, the underlying molecular mechanisms that cause the disease phenotypes remain elusive. Here, we utilize exome sequencing to identify genomic variants that lead to a homozygous amino acid substitution (p.[(Tyr71Cys)];[(Tyr71Cys)]) in human PUS3 of two affected individuals and a compound heterozygous substitution (p.[(Tyr71Cys)];[(Ile299Thr)]) in a third patient. We obtain wild-type and mutated full-length human recombinant PUS3 proteins and characterize the enzymatic activity in vitro. Unexpectedly, we find that the p.Tyr71Cys substitution neither affect tRNA binding nor pseudouridylation activity in vitro, but strongly impair the thermostability profile of PUS3, while the p.Ile299Thr mutation causes protein aggregation. Concomitantly, we observe that the PUS3 protein levels as well as the level of PUS3-dependent Ψ levels are strongly reduced in fibroblasts derived from all three patients. In summary, our results directly illustrate the link between the identified PUS3 variants and reduced Ψ levels in the patient cells, providing a molecular explanation for the observed clinical phenotypes.
Subject(s)
Hydro-Lyases , Intellectual Disability , Pseudouridine , Humans , Hydro-Lyases/genetics , Hydro-Lyases/metabolism , Intellectual Disability/genetics , Pseudouridine/genetics , Pseudouridine/metabolism , RNA Processing, Post-TranscriptionalABSTRACT
INTRODUCTION: Mutations in the KRT1 gene encoding keratin 1 cause epidermolytic hyperkeratosis characterized by blistering in the neonatal period followed by ichthyotic hyperkeratosis in childhood and adolescent life. We observed a spectrum of clinical manifestations of blistering disorders caused by different mutations in the same KRT1 gene. AIM: To analyse the phenotypic spectrum of blistering disorders caused by the KRT1 mutations. MATERIAL AND METHODS: Four patients with an epidermal barrier defect manifesting as blistering with the KRT1 mutations were included to the study. The clinical course of the disease was analysed, histology, immunofluorescence and electron microscopic examinations were performed. RESULTS: An adult patient with severe ichthyosis with p.Asn188Lys mutation in exon 1 of KRT1 who occasionally develops blisters in adolescence represents epidermolytic hyperkeratosis, a newborn child who died 4 days after birth due to disruption of the epidermal barrier (extensive blister and erosions) with mutation p.Ser193Pro in the KTR1 gene and two adult sisters harbouring heterozygous mutation c.591+1A>G in the KRT1 gene who present superficial blisters induced by mild trauma from the birth up to adolescent life without ichthyosis suggesting the diagnosis of epidermolysis bullosa simplex. Histopathology in all adult patients showed cytoplasm disruption in keratinocytes of the stratum spinosum with keratohyalin granule-like structures and, on the ultrastructural level, the presence of keratin clumping confirming the pathology of keratin intermediate filaments. CONCLUSIONS: This study extends the knowledge of the clinical spectrum for the KRT1 gene mutations. This is the first description of familial dominant epidermolysis bullosa simplex linked to the KRT1 mutation.
ABSTRACT
INTRODUCTION: Mutations in the TRPV4 gene are associated with neuromuscular disorders and skeletal dysplasias, which present a phenotypic overlap. METHODS: Next-generation sequencing and Sanger sequencing were used to analyze the TRPV4 gene. RESULTS: We present 2 Polish families with TRPV4-related disorder harboring the same p.Arg269His mutation. The disease phenotypic expression was extremely variable (from mild scapular winging to severe hypotonia, global weakness, inability to walk unaided, congenital contractures, scoliosis, and respiratory insufficiency), but did not suggest anticipation. The 2 most severely affected patients showed congenital distal contractures of the upper limbs and involvement of cranial nerves (manifesting as facial asymmetry and strabismus). The disease course seemed to be stable, although in later stages it caused respiratory insufficiency and progression of physical disability. DISCUSSION: The phenotypic variability observed in p.Arg269His carriers suggests that an additional modifier or a more complex pathogenic mechanism exists. Muscle Nerve 59:129-133, 2019.
Subject(s)
Arginine/genetics , Histidine/genetics , Muscular Atrophy, Spinal/genetics , Mutation/genetics , TRPV Cation Channels/genetics , Adult , Child, Preschool , Creatine Kinase/blood , Family Health , Female , Heterozygote , Humans , Male , Muscular Atrophy, Spinal/blood , Muscular Atrophy, Spinal/pathology , Transaminases/bloodABSTRACT
Cardio-facio-cutaneous syndrome (CFCS), a rare congenital disorder of RASopathies, displays high phenotypic variability. Complications during pregnancy and in the perinatal period are commonly reported. Polyhydramnios is observed in over half of pregnancies and might occur with fetal macrocephaly, macrosomia, and/or heart defects. Premature birth is not uncommon and any complications like respiratory insufficiency, edema, and feeding difficulties are present and might delay accurate clinical diagnosis. Besides neonatal complications, CFCS newborns and later infants have distinctive dysmorphic features usually accompanied by neurological (hypotonia with motor delay, neurocognitive delay) findings. Also, heart defects usually present at birth. Herein, we present the case of a female baby born prematurely from a pregnancy complicated with polyhydramnios, presenting at birth with craniofacial features typical for RASopathies, heart defects, neurological abnormalities, and hyperkeratosis unusual for a neonatal period. Due to the presence of a heart defect and other complications related to premature birth, the course of the disease was severe with a fatal outcome at the age of 9 months. The RASopathy, particularly CFCS, clinical diagnosis was confirmed and de novo p.Phe57Ile mutation in MAP2K2 was identified.
Subject(s)
Ectodermal Dysplasia/genetics , Ectodermal Dysplasia/pathology , Failure to Thrive/genetics , Failure to Thrive/pathology , Heart Defects, Congenital/genetics , Heart Defects, Congenital/pathology , MAP Kinase Kinase 2/genetics , Facies , Fatal Outcome , Female , Humans , Infant, Newborn , Mutation , PhenotypeABSTRACT
The presence of dynamic mutation in the FMR1 gene localized on the X chromosome (Xq28) is the major cause of Fragile X syndrome. As this syndrome is quite frequently diagnosed in patients with intellectual disability and autism spectrum disorders, the genetic testing of the FMR1 gene is a routine procedure performed in these patients. Molecular methods based on the PCR technique are used commonly, as they allow to identify normal (up to 54 CGG repeats, including grey zone alleles - 45-54 CGG repeats), premutation (55-200 CGG repeats) and full mutation (>200 CGG repeats) alleles.The article presents the basic methods used in the molecular diagnosis of Fragile X syndrome and other FMR1-related disorders. The following methods are presented: a screening test with GeneScan analysis, TP-PCR based tests and methods used for methylation analysis. Their pros and cons, as well as the resulting interpretation are discussed. Moreover, there is a presentation of the molecular diagnostic scheme following European Molecular Genetics Quality Network guidelines used in the Department of Medical Genetics.
Subject(s)
DNA Repeat Expansion , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/diagnosis , Ataxia/diagnosis , Ataxia/genetics , Female , Fragile X Syndrome/genetics , Humans , Male , Mutation , Practice Guidelines as Topic , Primary Ovarian Insufficiency/diagnosis , Primary Ovarian Insufficiency/genetics , Tremor/diagnosis , Tremor/geneticsABSTRACT
Fragile X syndrome (FXS) is the second most common inherited cause of intellectual disability (ID), after Down syndrome. The severity of ID in FXS patients varies and depends mainly on the patient's sex. Besides intellectual disorders, additional symptoms, such as psychomotor delay, a specific behavioral phenotype, or emotional problems are present in FXS patients. In over 99% of the cases, the disease is caused by the presence of a dynamic mutation in the FMR1 gene localized on the X chromosome. Due to the expansion of CGG nucleotides (over 200 repeats), FMR1 gene expression is decreased and results in the significant reduction of the FMRP protein level. The CGG expansion to premutation range (55-200 CGG repeats) is equivalent to the FXS carrier status and may cause FMR1-dependent disorders - fragile X-associated primary ovarian insufficiency (FXPOI) and fragile X-associated tremor/ataxia syndrome (FXTAS). In contrast to FXS, clinical symptoms of these diseases occur later in adulthood. The aim of the article is to present the knowledge about the molecular background and epidemiology of fragile X syndrome and other FMR1-related disorders.
Subject(s)
Ataxia/pathology , DNA Repeat Expansion , Fragile X Mental Retardation Protein/genetics , Fragile X Syndrome/pathology , Gene Expression Regulation , Primary Ovarian Insufficiency/pathology , Tremor/pathology , Ataxia/epidemiology , Ataxia/genetics , Ataxia/metabolism , Female , Fragile X Syndrome/epidemiology , Fragile X Syndrome/genetics , Fragile X Syndrome/metabolism , Humans , Male , Mutation , Primary Ovarian Insufficiency/epidemiology , Primary Ovarian Insufficiency/genetics , Primary Ovarian Insufficiency/metabolism , Tremor/epidemiology , Tremor/genetics , Tremor/metabolismABSTRACT
INTRODUCTION: Mutations in the COL12A1 (collagen, type XII, alpha 1) gene have been described in a milder Bethlem-like myopathy in 6 patients from 3 families (dominant missense), and in a severe congenital form with failure to attain ambulation in 2 patients in a single pedigree (recessive loss-of-function). METHODS: We describe an 8-year-old girl of Polish origin who presented with profound hypotonia and joint hyperlaxity at birth after a pregnancy complicated by oligohydramnios and intrauterine growth retardation. RESULTS: We identified a novel, potentially pathogenic heterozygous missense COL12A1 c.8329G>C (p.Gly2777Arg) variant using a targeted sequencing panel. Patient fibroblast studies confirmed intracellular retention of the COL12A1 protein, consistent with a dominant-negative mutation. CONCLUSIONS: As our patient showed a more intermediate phenotype, this case expands the phenotypic spectrum for COL12A1 disorders. So far, COL12A1 disorders seem to cover much of the severity range of an Ehlers-Danlos/Bethlem-like myopathy overlap syndrome associated with both connective tissue abnormalities and muscle weakness. Muscle Nerve 55: 277-281, 2017.
Subject(s)
Collagen Type XII/genetics , Extracellular Matrix/metabolism , Polymorphism, Single Nucleotide/genetics , Child , Female , Humans , Muscular Diseases/genetics , Muscular Diseases/metabolism , Muscular Diseases/pathologyABSTRACT
BACKGROUND: Noonan syndrome is an autosomal dominant, multisystemic disorder caused by dysregulation of the RAS/mitogen activated protein kinase (MAPK) pathway. Heterozygous, pathogenic variants in 11 known genes account for approximately 80% of cases. The identification of novel genes associated with Noonan syndrome has become increasingly challenging, since they might be responsible for very small fractions of the cases. METHODS: A cohort of 50 Brazilian probands negative for pathogenic variants in the known genes associated with Noonan syndrome was tested through whole-exome sequencing along with the relatives in the familial cases. Families from the USA and Poland with mutations in the newly identified genes were included subsequently. RESULTS: We identified rare, segregating or de novo missense variants in SOS2 and LZTR1 in 4% and 8%, respectively, of the 50 Brazilian probands. SOS2 and LZTR1 variants were also found to segregate in one American and one Polish family. Notably, SOS2 variants were identified in patients with marked ectodermal involvement, similar to patients with SOS1 mutations. CONCLUSIONS: We identified two novel genes, SOS2 and LZTR1, associated with Noonan syndrome, thereby expanding the molecular spectrum of RASopathies. Mutations in these genes are responsible for approximately 3% of all patients with Noonan syndrome. While SOS2 is a natural candidate, because of its homology with SOS1, the functional role of LZTR1 in the RAS/MAPK pathway is not known, and it could not have been identified without the large pedigrees. Additional functional studies are needed to elucidate the role of LZTR1 in RAS/MAPK signalling and in the pathogenesis of Noonan syndrome.
Subject(s)
Genetic Association Studies , Genetic Variation , Noonan Syndrome/genetics , Son of Sevenless Proteins/genetics , Transcription Factors/genetics , Cohort Studies , Facies , Female , Humans , Male , Mitogen-Activated Protein Kinases/metabolism , Noonan Syndrome/diagnosis , Pedigree , Phenotype , Signal Transduction , ras Proteins/metabolismABSTRACT
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by congenital malformations of the great toes and progressive heterotopic ossification of connective tissue that begins during the first decade of life. Our patient presented with intrauterine growth retardation, respiratory distress, neonatal onset soft tissue masses, bilateral hallux valgus, and congenital anomalies of the thyroid and uterus. She was initially diagnosed with atypical infantile myofibromatosis based on clinical and pathological findings. She underwent whole-exome sequencing (WES) as part of the FORGE study to identify the gene for infantile myofibromatosis; however a de novo dominant mutation in ACVR1 (NM_001105.4:c.617G>A) revised the diagnosis to FOP. This patient highlights the utility of WES as an early diagnostic tool in the investigation of patients with unusual presentations of rare diseases, thereby providing clinicians with accurate molecular diagnoses and the opportunity to tailor clinical management to improve patient care.
Subject(s)
Activin Receptors, Type I/genetics , Fetal Growth Retardation/genetics , Hallux Valgus/genetics , Mutation , Myositis Ossificans/genetics , Respiratory Distress Syndrome, Newborn/genetics , Child, Preschool , Exome , Fatal Outcome , Female , Fetal Growth Retardation/diagnosis , Fetal Growth Retardation/pathology , Hallux Valgus/diagnosis , Hallux Valgus/pathology , High-Throughput Nucleotide Sequencing , Humans , Myositis Ossificans/diagnosis , Myositis Ossificans/pathology , Respiratory Distress Syndrome, Newborn/diagnosis , Respiratory Distress Syndrome, Newborn/pathology , Thyroid Gland/abnormalities , Uterus/abnormalitiesABSTRACT
Neurofibromatosis type I (NF1) is multisystemic disease characterized by pigmentary skin changes, increased susceptibility to tumor formation, neurological deficits and skeletal defects. The disease is a monogenic, autosomal dominant disorder, caused by the presence of mutations in the NF1 gene encoding neurofibromin - a multifunctional regulatory protein. The basic function of neurofibromin protein is modulation of the RAS protein activity necessary for regulation of cell proliferation and differentiation by the RAS/MAPK and RAS/PI3K/AKT signal transduction pathways. In addition, neurofibromin is a regulator of adenylate cyclase activity and therefore may interfere with signaling by the cAMP/protein kinase A pathway that regulates cell cycle progression or learning and memory formation processes. Neurofibromin also interacts with many other proteins that are engaged in intracellular transport (tubulin, kinesin), actin cytoskeleton rearrangements (LIMK2, Rho and Rac) or morphogenesis of neural cells (syndecans, CRMP proteins). The activity of neurofibromin is strictly regulated by the expression of different NF1 mRNA isoforms depending on tissue type or period in organism development, the protein localization, posttranslational modifications (phosphorylation, ubiquitination) or interactions with other proteins (e.g. 14-3-3). The fact that neurofibromin is engaged in many cellular processes has significant consequences when the proper protein functioning is impaired due to decreased protein level or activity. It affects the normal cell function and results in disturbances of organism development that lead to the occurrence of clinical signs specific for NF1. In the article, the basic neurofibromin functions are presented in the context of the molecular pathogenesis of NF1.
Subject(s)
Mutation , Neurofibromatosis 1/genetics , Neurofibromin 1/genetics , Signal Transduction , Alternative Splicing , Humans , Neurofibromatosis 1/metabolism , Neurofibromin 1/metabolism , Neurofibromin 1/physiology , Protein Conformation , Protein Processing, Post-TranslationalABSTRACT
Inherited metabolic disorders, also referred to as inborn errors of metabolism (IEM), are a group of congenital disorders caused by mutation in genomic or mitochondrial DNA. IEM are mostly rare disorders with incidence ranging from 1/50,000-1/150,000), however in total IEM may affect even 1/1000 people. A particular mutation affects specific protein or enzyme that improper function leads to alterations in specific metabolic pathway. Inborn errors of metabolism are monogenic disorders that can be inherited in autosomal recessive manner or, less frequently, in autosomal dominant or X-linked patterns. Some exceptions to Mendelian rules of inheritance have also been described. Vast majority of mutations responsible for IEM are small DNA changes affecting single or several nucleotides, although larger rearrangements were also identified. Therefore, the methods used for the identification of pathogenic mutations are mainly based on molecular techniques, preferably on Sanger sequencing. Moreover, the next generation sequencing technique seems to be another prospective method that can be successfully implemented for the diagnosis of inborn errors of metabolism. The identification of the genetic defect underlying the disease is not only indispensable for genetic counseling, but also might be necessary to apply appropriate treatment to the patient. Therapeutic strategies for IEM are continuously elaborated and tested (eg. enzyme replacement therapy, specific cells or organ transplantation or gene therapy, both in vivo and ex vivo) and have already been implemented for several disorders. In this article we present current knowledge about various aspects of IEM on the basis of our own experience and literature review.
Subject(s)
Genetic Testing/methods , Metabolism, Inborn Errors/diagnosis , Metabolism, Inborn Errors/therapy , Neonatal Screening/methods , Humans , Incidence , Infant, Newborn , Metabolism, Inborn Errors/epidemiology , Metabolism, Inborn Errors/genetics , Rare Diseases , Risk FactorsABSTRACT
Neurofibromatosis type I (NF1) is a disease associated with the presence of benign neurofibromas and malignant tumours of the central and peripheral nervous system, that are accompanied by characteristic changes in the skin, such as café-au-lait spots or axillary freckling. In 50% of NF1 patients, the clinical symptoms become apparent below 1st year and in 97%, before the age of 8 years. The disease is mainly caused by the presence of mutation in the NF1 gene that encodes neurofibromin - a protein involved in the regulation of several cellular signaling pathways responsible for cell proliferation and differentiation. Neurofibromin is necessary for embryonic development and involved mainly in the differentiation of neural crest derived cells, mesenchymal cells, neural cells, melanocytes and bone cells. Type I neurofibromatosis is inherited in autosomal dominant manner, nevertheless about 50% of detected mutations are de novo ones. The mutations have full penetrance, although they also have significant pleiotropic effect. Over 1485 different mutations have been identified in the NF1 gene so far, most of which lead to a synthesis of truncated, non-functional protein. It is estimated that the point mutations are responsible for approximately 90% of cases of NF1. The remaining 5-7% of NF1 cases are associated with the presence of a single exon or whole NF1 gene deletion (17q11.2 microdeletion syndrome). The article discusses the role of neurofibromin in cell signaling with the special attention to RAS/MAPK pathway regulation as well as in organism development. Also the basic methods of molecular analysis of NF1 gene are presented in the context of their application in the diagnosis and clinical differentiation of the disease.
Subject(s)
Mutation , Neurofibromatosis 1/genetics , Neurofibromin 1/genetics , Cafe-au-Lait Spots/genetics , Gene Deletion , Humans , Mitogen-Activated Protein Kinases/metabolism , Point Mutation , Signal Transduction/genetics , ras Proteins/metabolismABSTRACT
The RASopathies are a class of developmental syndromes. Each of them exhibits distinctive phenotypic features, although there are numerous overlapping clinical manifestations that include: dysmorphic craniofacial features, congenital cardiac defects, skin abnormalities, varying degrees of intellectual disability and increased risk of malignancies. These disorders include: Noonan syndrome, Costello syndrome, LEOPARD syndrome, cardio-facio-cutaneous syndrome (CFC), capillary malformation-arteriovenous malformation syndrome (CM-AVM), Legius syndrome and neurofibromatosis type 1 (NF1). The RASopathies are associated with the presence of germline mutation in genes encoding specific proteins of the RAS/mitogen - activated protein kinase (MAPK) pathway that plays a crucial role in embryonic and postnatal development. In this review, we present the clinical and molecular features of selected syndromes from the RASopathies group.
Subject(s)
Arteriovenous Malformations/genetics , Capillaries/abnormalities , Craniofacial Abnormalities/genetics , Ectodermal Dysplasia/genetics , Failure to Thrive/genetics , Germ-Line Mutation , Heart Defects, Congenital/genetics , Mitogen-Activated Protein Kinases/genetics , Neurofibromatosis 1/genetics , Port-Wine Stain/genetics , ras Proteins/genetics , Costello Syndrome , Facies , Humans , LEOPARD Syndrome/genetics , MAP Kinase Signaling System/genetics , Noonan Syndrome , Signal Transduction/geneticsABSTRACT
The 270th ENMC workshop aimed to develop a common procedure to optimize the reliability of SMN2 gene copy number determination and to reinforce collaborative networks between molecular scientists and clinicians. The workshop involved neuromuscular and clinical experts and representatives of patient advocacy groups and industry. SMN2 copy number is currently one of the main determinants for therapeutic decision in SMA patients: participants discussed the issues that laboratories may encounter in this molecular test and the cruciality of the accurate determination, due the implications as prognostic factor in symptomatic patients and in individuals identified through newborn screening programmes. At the end of the workshop, the attendees defined a set of recommendations divided into four topics: SMA molecular prognosis assessment, newborn screening for SMA, SMN2 copies and treatments, and modifiers and biomarkers. Moreover, the group draw up a series of recommendations for the companies manufacturing laboratory kits, that will help to minimize the risk of errors, regardless of the laboratories' expertise.
Subject(s)
Muscular Atrophy, Spinal , Survival of Motor Neuron 2 Protein , Humans , Biomarkers/analysis , Consensus Development Conferences as Topic , Gene Dosage , Muscular Atrophy, Spinal/diagnosis , Muscular Atrophy, Spinal/genetics , Prognosis , Survival of Motor Neuron 2 Protein/geneticsABSTRACT
Noonan syndrome (NS) is one of the most common genetic conditions inherited mostly in an autosomal dominant manner with vast heterogeneity in clinical and genetic features. Patients with NS might have speech disturbances, memory and attention deficits, limitations in daily functioning, and decreased overall intelligence. Here, 34 patients with Noonan syndrome and 23 healthy controls were enrolled in a study involving gray and white matter volume evaluation using voxel-based morphometry (VBM), white matter connectivity measurements using diffusion tensor imaging (DTI), and resting-state functional magnetic resonance imaging (rs-fMRI). Fractional anisotropy (FA) and mean diffusivity (MD) probability distributions were calculated. Cognitive abilities were assessed using the Stanford Binet Intelligence Scales. Reductions in white matter connectivity were detected using DTI in NS patients. The rs-fMRI revealed hyper-connectivity in NS patients between the sensorimotor network and language network and between the sensorimotor network and salience network in comparison to healthy controls. NS patients exhibited decreased verbal and nonverbal IQ compared to healthy controls. The assessment of the microstructural alterations of white matter as well as the resting-state functional connectivity (rsFC) analysis in patients with NS may shed light on the mechanisms responsible for cognitive and neurofunctional impairments.
Subject(s)
Diffusion Tensor Imaging , Noonan Syndrome , Humans , Diffusion Tensor Imaging/methods , Proto-Oncogene Proteins p21(ras) , Magnetic Resonance Imaging , Noonan Syndrome/genetics , Cognition , Mitogen-Activated Protein Kinases , Signal TransductionABSTRACT
Lysine-specific demethylase 5C (KDM5C) has been identified as an important chromatin remodeling gene, contributing to X-linked neurodevelopmental disorders (NDDs). The KDM5C gene, located in the Xp22 chromosomal region, encodes the H3K4me3-me2 eraser involved in neuronal plasticity and dendritic growth. Here we report 30 individuals carrying 13 novel and one previously identified KDM5C variants. Our cohort includes the first reported case of somatic mosaicism in a male carrying a KDM5C nucleotide substitution, and a dual molecular finding in a female carrying a homozygous truncating FUCA1 alteration together with a de novo KDM5C variant. With the use of next generation sequencing strategies, we detected 1 frameshift, 1 stop codon, 2 splice-site and 10 missense variants, which pathogenic role was carefully investigated by a thorough bioinformatic analysis. The pattern of X-chromosome inactivation was found to have an impact on KDM5C phenotypic expression in females of our cohort. The affected individuals of our case series manifested a neurodevelopmental condition characterized by psychomotor delay, intellectual disability with speech disorders, and behavioral features with particular disturbed sleep pattern; other observed clinical manifestations were short stature, obesity and hypertrichosis. Collectively, these findings expand the current knowledge about the pathogenic mechanisms leading to dysfunction of this important chromatin remodeling gene and contribute to a refinement of the KDM5C phenotypic spectrum.
Subject(s)
Intellectual Disability , Lysine , Humans , Male , Female , Lysine/genetics , Mutation , Histone Demethylases/genetics , Histone Demethylases/metabolism , Intellectual Disability/genetics , Chromatin , Frameshift MutationABSTRACT
Noonan syndrome (NS) is one of the most frequent dysmorphic syndromes in children with a frequency of 1/1000-1/2500 of newborns. Noonan syndrome is a multi-organ disease with a broad spectrum of clinical symptoms. The most characteristic features of NS are: craniofacial dysmorphy, short stature, cardiovascular defects, bone and skeletal defects and delayed puberty (cryptorchidism in males). Noonan syndrome has a genetic background and is inherited in autosomal dominant manner. The recent studies have shown that it is due to the presence of mutation in one of the genes encoding proteins of RAS/MAPK signalling pathway responsible for cell proliferation and differentiation. Till now, NS causing mutations were identified in PTPN11, SOS1, RAF1, KRAS, BRAF, SHOC2 and NRAS genes, and this may partially explain the broad phenotypic spectrum observed in patients. Noonan syndrome is one of the RAS-opathies, therefore the molecular analysis of RAS/ MAPK genes might be a very useful tool in clinical differentiation of the disease.
Subject(s)
Genes, ras/genetics , MAP Kinase Signaling System/genetics , Mutation , Noonan Syndrome/genetics , Humans , Noonan Syndrome/classificationABSTRACT
Copy-number variants (CNVs) collectively represent an important cause of neurodevelopmental disorders such as developmental delay (DD)/intellectual disability (ID), autism, and epilepsy. In contrast to DD/ID, for which the application of microarray techniques enables detection of pathogenic CNVs in -10-20% of patients, there are only few studies of the role of CNVs in epilepsy and genetic etiology in the vast majority of cases remains unknown. We have applied whole-genome exon-targeted oligonucleotide array comparative genomic hybridization (array CGH) to a cohort of 102 patients with various types of epilepsy with or without additional neurodevelopmental abnormalities. Chromosomal microarray analysis revealed 24 non-polymorphic CNVs in 23 patients, among which 10 CNVs are known to be clinically relevant. Two rare deletions in 2q24.1q24.3, including KCNJ3 and 9q21.13 are novel pathogenic genetic loci and 12 CNVs are of unknown clinical significance. Our results further support the notion that rare CNVs can cause different types of epilepsy, emphasize the efficiency of detecting novel candidate genes by whole-genome array CGH, and suggest that the clinical application of array CGH should be extended to patients with unexplained epilepsies.
Subject(s)
Developmental Disabilities/genetics , Epilepsy/genetics , Genome, Human , Adolescent , Autistic Disorder/complications , Autistic Disorder/genetics , Child , Child, Preschool , Comparative Genomic Hybridization/methods , DNA Copy Number Variations , Developmental Disabilities/complications , Epilepsy/complications , Exons , Gene Dosage , Humans , Infant , Intellectual Disability/complications , Intellectual Disability/genetics , MaleABSTRACT
Spinal muscular atrophy (SMA) affects one in 7,500-10,000 newborns. Before the era of disease-modifying therapies, it used to be the major genetic cause of mortality in infants. Currently, there are three therapies approved for SMA, including two molecules modifying the splicing of the SMN2 gene and one gene therapy providing a healthy copy of the SMN gene with a viral vector. The best effects of any of these therapies are achieved when the treatment is administered in the presymptomatic stage of the disease, therefore newborn screening programs are being introduced in many countries. Patients identified in newborn screening might be eligible for gene therapy. However, gene therapy and the associated administration of steroids in newborns might interfere with the vaccination schedule, which includes live immunization against tuberculosis in some countries. The timing of gene therapy in patients who received live vaccinations has not yet been addressed neither in the clinical trials nor in the existing international guidelines. The Polish Vaccinology Association has developed the first recommendations for gene therapy administration in newborns who received live vaccination against tuberculosis. Their statement was implemented in the current guidelines for Polish SMA patients identified in the newborn screening program and might be helpful for medical professionals in other countries where live vaccine against tuberculosis is still in routine use in newborns.