Research on the Pathogenesis of Cognitive and Neurofunctional Impairments in Patients with Noonan Syndrome: The Role of Rat Sarcoma-Mitogen Activated Protein Kinase Signaling Pathway Gene Disturbances

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.

Genetic Risk Factors for Neurological Disorders in Children with Adverse Events Following Immunization: A Descriptive Study of a Polish Case Series

Studies conducted on large populations show a lack of connection between vaccination and serious neurological symptoms. However, there are isolated cases that indicate such a relationship. These reports on adverse effects following immunization (AEFI) reduce social confidence in vaccination; however, their background may be rare genetic defects. The aim of the presented study was to examine if neurological AEFI in children may be associated with variants in genes related to neurodevelopment. To identify such possible associations, a descriptive study of the Polish case series was conducted. We performed next-generation sequencing in patients who, up to 4 weeks of injection of any vaccine, manifested neurological AEFI. We included 23 previously normally developing children with first seizures that occurred after vaccination. We identified pathogenic/likely pathogenic variants in genes engaged in neurodevelopment in nine patients and variants of uncertain significance in another nine patients. The mutated genes belonged to the group of genes related to epilepsy syndromes/epileptic encephalopathy. We showed that AEFI might have a genetic background. We hypothesized that in some AEFI patients, the vaccine might only trigger neurological symptoms that would have been manifested anyway as a result of a pathogenic variant in a gene engaged in neurodevelopment.

Application of array comparative genomic hybridization (aCGH) for identification of chromosomal aberrations in the recurrent pregnancy loss

Spontaneous abortion occurs in 8–20% of recognized pregnancies and usually takes place in the first trimester (7–11 weeks). There are many causes of pregnancy loss, but the most important (about 75%) is the presence of chromosomal aberrations. We present the results of oligonucleotide array application in a cohort of 62 miscarriage cases. The inclusion criteria for the study were the loss after 8th week of pregnancy and the appearance of recurrent miscarriages. DNA was extracted from trophoblast or fetal skin fibroblasts. In the 62 tested materials from recurrent miscarriages, the detection rate was 56.5% (35/62). The most commonly found were aneuploidies (65%) (chromosomal trisomy 14, 16, 18, 21, and 22), Turner syndrome, and triploidy (17.1%). Other chromosomal abnormalities included pathogenic and likely pathogenic structural aberrations: 1) pathogenic: deletion 7p22.3p12.3 and duplication 9p24.3p13.2 inherited from the normal father, deletion 3q13.31q22.2 and deletion 3q22.3q23 of unknown inheritance and duplication of 17p12 inherited from father with foot malformation; 2) likely pathogenic variants: deletion 17p13.1 inherited from normal mother, deletion 5q14.3 of unknown inheritance and de novo deletion 1q21.1q21.2. Among these aberrations, six CNVs (copy number variants) were responsible for the miscarriage: deletion 7p22.3p12.3 and duplication 9p24.3p13.2, deletion 3q13.31q22.2 and deletion 3q22.3q23, and deletion 17p13.1 and deletion 1q21.1q21.2. Other two findings were classified as incidental findings (deletion 5q14.3 and 17p12 duplication). Our research shows that 17% of the aberrations (6/35 abnormal results) that cannot be identified by the routine kariotype analysis are structural aberrations containing genes important for fetal development, the mutations of which may cause spontaneous abortion.

WDR13: A Novel Gene Implicated in Non-Syndromic Intellectual Disability

Investigating novel genetic variants involved in intellectual disability (ID) development is essential. X-linked intellectual disability (XLID) accounts for over 10% of all cases of ID in males. XLID genes are involved in many cellular pathways and processes. Some of them are not specific to the development and functioning of the neural system. The implementation of exome sequencing simplifies the search for novel variants, especially those less expected. Here, we describe a nonsense variant of the XLID gene, WDR13. The mutation c.757C>T (p.Arg253Ter) was uncovered by X-chromosome exome sequencing in males with a familial form of intellectual disability. Quantitative PCR (qPCR) analysis showed that variant c.757C>T caused a significant decrease in WDR13 expression in the patient's fibroblast. Moreover, it dysregulated other genes linked to intellectual disability, such as FMR1, SYN1, CAMK2A, and THOC2. The obtained results indicate the pathogenic nature of the detected variant and suggest that the WDR13 gene interacts with other genes essential for the functioning of the nervous system, especially the synaptic plasticity process.

The retrospective molecular analysis of large or giant congenital melanocytic nevi in a group of Polish children

Background

Large and giant congenital melanocytic nevi (CMN), benign naevomelanocytic proliferations derived from neural crests, with a projected adult size (PAS) ≥ 20 cm, are connected to a high risk of melanoma and neurocutaneous melanosis. Among several factors, genetic alterations seem to be involved in tumorigenesis. The aim of the present study was to analyse the mutation status of NRAS and BRAF genes in resection specimens from large or giant CMN in a group of Polish patients.

Material and methods

The formalin-fixed, paraffin-embedded resection specimens from 18 patients, fixed in the years of 2006 to 2017, were included in the study. The regions containing the highest load of melanocytes were macrodissected prior to DNA isolation. The NRAS and BRAF mutation status was evaluated using qPCR.

Results

We detected activating mutations in NRAS gene (codons: 12 and 61) in 7 out of the 18 (38.9%) patients. No BRAF mutations were found.

Conclusion

Our study, the first molecular analysis of large/giant CMN in Polish patients, supports the hypothesis that NRAS mutation in codon 61 are frequent, recurrent mutations in large/giant CMN. Moreover, we show, for the first time, that NRAS mutations in codon 12 (p.Gly12Asp) can be also detected in giant CMN. The exact role of these genetic alterations in CMN formation remains to be elucidated.

Ectodermal dysplasias – molecular mechanisms responsible for occurrence of most frequent syndroms

Ectodermal dysplasias are a wide group of genetic disorders characterised by clinical symptoms in ectodermal derivatives (most frequently teeth, hair, nails and sweat glands). There is a number of genes, which, if mutated, can cause the specified phenotype. The molecular basis of many ectodermal dysplasias have been investigated. The phenotype often results from the imparied communication in molecular pathways important in embryonic morphogenesis or disturbed function of protein complexes involved in homeostasis, adhesion and stability of the cells in the tissue. Different classification systems have been proposed to group ectodermal dysplasias according to clinical symptoms or molecular basis. Molecular technologies have let recently to expand diagnostic abilities for ectodermal dysplasias patients. Certainly in the nearest years new genes and mutations will be discovered as a cause of ectodermal dysplasias.

The genetic basis of classical galactosaemia in Polish patients

Classic galactosemia (OMIM #230400) is an autosomal recessive disorder caused by homozygous or compound heterozygous pathogenic variants in the galactose-1-phosphate uridylyltransferase gene (GALT; 606999) on chromosome 9p13. Its diagnosis is established by detecting elevated erythrocyte galactose-1-phosphate concentration, reduced erythrocyte galactose-1-phosphate uridylyltransferase (GALT) enzyme activity. Biallelic pathogenic variants in the GALT gene is confirmed by DNA analysis. Our paper presents molecular characteristics of 195 Polish patients diagnosed with galactosemia I, intending to expand the current knowledge of this rare disease's molecular etiology. To the best of our knowledge, the described cohort of galactosemia patients is the largest single-center cohort presented so far.

The MED13L haploinsufficiency syndrome associated with de novo nonsense variant (P.GLN1981*)

The Mediator complex subunit 13-like is a part of the large Mediator complex. Recently, a large number of patients were diagnosed with mutations in this gene, which makes it one of the most frequent causes of syndromic intellectual disability. In this work, we report a patient with a novel de novo likely pathogenic variant c.5941C>T, p.(Gln1981*) in the MED13L gene with severe intellectual disability and facial dysmorphism. Uncommon findings like lack of speech, strabismus and self-destructive behaviour present in our patient allowed us to further define the phenotypic spectrum of mental retardation and distinctive facial features with or without cardiac defects syndrome.

Novel and recurrent variants of ATP2C1 identified in patients with Hailey-Hailey disease

Hailey-Hailey disease (HHD) is a rare, late-onset autosomal dominant genodermatosis characterized by blisters, vesicular lesions, crusted erosions, and erythematous scaly plaques predominantly in intertriginous regions. HHD is caused by ATP2C1 mutations. About 180 distinct mutations have been identified so far; however, data of only few cases from Central Europe are available. The aim was to analyze the ATP2C1 gene in a cohort of Polish HHD patients. A group of 18 patients was enrolled in the study based on specific clinical symptoms. Mutations were detected using Sanger or next generation sequencing. In silico analysis was performed by prediction algorisms and dynamic structural modeling. In two cases, mRNA analysis was performed to confirm aberrant splicing. We detected 13 different mutations, including 8 novel, 2 recurrent (p.Gly850Ter and c.325-3 T > G), and 6 sporadic (c.423-1G > T, c.899 + 1G > A, p.Leu539Pro, p.Thr808TyrfsTer16, p.Gln855Arg and a complex allele: c.[1610C > G;1741 + 3A > G]). In silico analysis shows that all novel missense variants are pathogenic or likely pathogenic. We confirmed pathogenic status for two novel variants c.325-3 T > G and c.[1610C > G;1741 + 3A > G] by mRNA analysis. Our results broaden the knowledge about genetic heterogeneity in Central European patients with ATP2C1 mutations and also give further evidence that careful and multifactorial evaluation of variant pathogenicity status is essential.

A novel de novo mutation p.Ala428Asp in KRT5 gene as a cause of localized epidermolysis bullosa simplex

Epidermolysis bullosa is a group of inherited blistering skin diseases resulting in most cases from missense mutations in KRT5 and KRT14 genes encoding the basal epidermal keratins 5 and 14. Here, we present a patient diagnosed with a localized subtype of epidermolysis bullosa simplex caused by a heterozygous mutation p.Ala428Asp in the KRT5 gene, that has not been previously identified. Moreover, a bioinformatic analysis of the novel mutation was performed, showing changes in the interaction network between the proteins. Identification of novel mutations and genotype-phenotype correlations allow to better understanding of underlying pathophysiologic bases and is important for genetic counselling, patients' management, and disease course prediction.

FRMPD4 mutations cause X-linked intellectual disability and disrupt dendritic spine morphogenesis

FRMPD4 (FERM and PDZ Domain Containing 4) is a neural scaffolding protein that interacts with PSD-95 to positively regulate dendritic spine morphogenesis, and with mGluR1/5 and Homer to regulate mGluR1/5 signaling. We report the genetic and functional characterization of 4 FRMPD4 deleterious mutations that cause a new X-linked intellectual disability (ID) syndrome. These mutations were found to be associated with ID in ten affected male patients from four unrelated families, following an apparent X-linked mode of inheritance. Mutations include deletion of an entire coding exon, a nonsense mutation, a frame-shift mutation resulting in premature termination of translation, and a missense mutation involving a highly conserved amino acid residue neighboring FRMPD4-FERM domain. Clinical features of these patients consisted of moderate to severe ID, language delay and seizures alongside with behavioral and/or psychiatric disturbances. In-depth functional studies showed that a frame-shift mutation, FRMPD4p.Cys618ValfsX8, results in a disruption of FRMPD4 binding with PSD-95 and HOMER1, and a failure to increase spine density in transfected hippocampal neurons. Behavioral studies of frmpd4-KO mice identified hippocampus-dependent spatial learning and memory deficits in Morris Water Maze test. These findings point to an important role of FRMPD4 in normal cognitive development and function in humans and mice, and support the hypothesis that FRMPD4 mutations cause ID by disrupting dendritic spine morphogenesis in glutamatergic neurons.

MAP2K2 mutation as a cause of cardio-facio-cutaneous syndrome in an infant with a severe and fatal course of the disease

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.

Comprehensive genomic analysis of patients with disorders of cerebral cortical development

Malformations of cortical development (MCDs) manifest with structural brain anomalies that lead to neurologic sequelae, including epilepsy, cerebral palsy, developmental delay, and intellectual disability. To investigate the underlying genetic architecture of patients with disorders of cerebral cortical development, a cohort of 54 patients demonstrating neuroradiologic signs of MCDs was investigated. Individual genomes were interrogated for single-nucleotide variants (SNV) and copy number variants (CNV) with whole-exome sequencing and chromosomal microarray studies. Variation affecting known MCDs-associated genes was found in 16/54 cases, including 11 patients with SNV, 2 patients with CNV, and 3 patients with both CNV and SNV, at distinct loci. Diagnostic pathogenic SNV and potentially damaging variants of unknown significance (VUS) were identified in two groups of seven individuals each. We demonstrated that de novo variants are important among patients with MCDs as they were identified in 10/16 individuals with a molecular diagnosis. Three patients showed changes in known MCDs genes  and a clinical phenotype beyond the usual characteristics observed, i.e., phenotypic expansion, for a particular known disease gene clinical entity. We also discovered 2 likely candidate genes, CDH4, and ASTN1, with human and animal studies supporting their roles in brain development, and 5 potential candidate genes. Our findings emphasize genetic heterogeneity of MCDs disorders and postulate potential novel candidate genes involved in cerebral cortical development.

[Fragile X syndrome and FMR1-dependent diseases - clinical presentation, epidemiology and molecular background]

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.

[Fragile X syndrome and FMR1-dependent diseases - diagnostic scheme based on own experience .]

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.

Hearing impairment caused by mutations in two different genes responsible for nonsyndromic and syndromic hearing loss within a single family

Usher syndrome is rare genetic disorder impairing two human senses, hearing and vision, with the characteristic late onset of vision loss. This syndrome is divided into three types. In all cases, the vision loss is postlingual, while loss of hearing is usually prelingual. The vestibular functions may also be disturbed in Usher type 1 and sometimes in type 3. Vestibular areflexia is helpful in making a proper diagnosis of the syndrome, but, often, the syndrome is misdiagnosed as a nonsyndromic hearing loss. Here, we present a Polish family with hearing loss, which was clinically classified as nonsyndromic. After excluding mutations in the DFNB1 locus, we implemented the next-generation sequencing method and revealed that hearing loss was syndromic and mutations in the USH2A gene indicate Usher syndrome. This research highlights the importance of molecular analysis in establishing a clinical diagnosis of congenital hearing loss.

Friedreich ataxia is not only a GAA repeats expansion disorder: implications for molecular testing and counselling

Friedreich ataxia (FRDA) is the most common hereditary ataxia. It is an autosomal recessive disorder caused by mutations of the FXN gene, mainly the biallelic expansion of the (GAA)n repeats in its first intron. Heterozygous expansion/point mutations or deletions are rare; no patients with two point mutations or a point mutation/deletion have been described, suggesting that loss of the FXN gene product, frataxin, is lethal. This is why routine FRDA molecular diagnostics is focused on (GAA)n expansion analysis. Additional tests are considered only in cases of heterozygous expansion carriers and an atypical clinical picture. Analyses of the parent's carrier status, together with diagnostic tests, are performed in rare cases, and, because of that, we may underestimate the frequency of deletions. Even though FXN deletions are characterised as 'exquisitely rare,' we were able to identify one case (2.4 %) of a (GAA)n expansion/exonic deletion in a group of 41 probands. This was a patient with very early onset of disease with rapid progression of gait instability and hypertrophic cardiomyopathy. We compared the patient's clinical data to expansion/deletion carriers available in the literature and suggest that, in clinical practice, the FXN deletion test should be taken into account in patients with early-onset, rapid progressive ataxia and severe scoliosis.

PEHO Syndrome May Represent Phenotypic Expansion at the Severe End of the Early-Onset Encephalopathies

BACKGROUND

Progressive encephalopathy with edema, hypsarrhythmia and optic atrophy (PEHO) syndrome is a distinct neurodevelopmental disorder. Patients without optic nerve atrophy and brain imaging abnormalities but fulfilling other PEHO criteria are often described as a PEHO-like syndrome. The molecular bases of both clinically defined conditions remain unknown in spite of the widespread application of genome analyses in both clinic and research.

METHODS

We enrolled two patients with a prior diagnosis of PEHO and two individuals with PEHO-like syndrome. All four individuals subsequently underwent whole-exome sequencing and comprehensive genomic analysis.

RESULTS

We identified disease-causing mutations in known genes associated with neurodevelopmental disorders including GNAO1 and CDKL5 in two of four individuals. One patient with PEHO syndrome and a de novoGNAO1 mutation was found to have an additional de novo mutation in HESX1 that is associated with optic atrophy.

CONCLUSIONS

We hypothesize that PEHO and PEHO-like syndrome may represent a severe end of the spectrum of the early-onset encephalopathies and, in some instances, its complex phenotype may result from an aggregated effect of mutations at two loci.

The clinical course of hereditary pancreatitis in children - A comprehensive analysis of 41 cases

BACKGROUND

Available data from adult patients do not reflect natural course of hereditary pancreatitis (HP) in children. To date, no study has assessed the clinical course of HP in children.

OBJECTIVE

To investigate the clinical course of HP in children and compare it to non-HP group with chronic pancreatitis (CP).

METHODS

A group of 265 children with CP, hospitalized from 1988 to 2014, were enrolled in the study. Medical records of those patients were reviewed for data on presentation, diagnostic findings and treatment. All children were screened for mutations in major pancreatitis-associated genes, i.e. PRSS1, SPINK1, and CFTR.

RESULTS

HP was diagnosed in 41 children (15.5%). Family history was positive in 88% of children with HP. Mutations of PRSS1 gene were found in 80% (33/41) of HP patients. We detected p.R122H, p.R122C, p.N29I, and p.E79K mutation in 34% (14/41), 27% (11/41), 12% (5/41), and 7% (3/41) of HP patients, respectively. Patients with paternal inheritance had first symptoms earlier than those with maternal inheritance (5.9 vs. 9.1 years; P < 0.05). Children with HP showed more severe changes in ERCP then those from non-HP group (2.05 Cambridge grade, vs. 1.6°; P < 0.05). ESWL was performed more frequently in HP group (12.2% vs. 3.1%; P < 0.05). There was no difference in age of disease onset (7.98 vs. 8.9 years; NS), pancreatic duct stenting (46.3% vs. 33%; NS), or number of surgical interventions (12.2% vs. 14.3%; NS) between both groups.

CONCLUSIONS

Children with HP reveal significantly more severe clinical presentation of the disease than non-HP patients, despite the same age of onset.

The efficacy of fluticasone furoate administered in the morning or evening is comparable in patients with persistent asthma

BACKGROUND

The inhaled corticosteroid fluticasone furoate (FF) is efficacious as a once-daily treatment for the management of asthma. Asthma is associated with circadian changes, with worsening lung function at night. We compared the efficacy of once-daily FF in the morning or evening for the treatment of asthma.

METHODS

Adults with persistent bronchial asthma were enrolled into this randomised, repeat-dose, double-blind, double-dummy, placebo-controlled, three-way crossover study. After a 14-day run-in period, patients received either: FF 100 μg in the morning (AM); FF 100 μg in the evening (PM); or placebo, via the ELLIPTA(®) dry powder inhaler. Patients received all three treatments (14 ± 2 day duration) separated by a 14- to 21-day washout period. The primary endpoint was 24-h weighted mean forced expiratory volume in 1 s (FEV1) measured at the end of each 14-day treatment.

RESULTS

A total of 28 patients aged between 19 and 67 years were randomised and 21 (75%) completed all three study arms. Once-daily administration of FF 100 μg resulted in an increased 24-hour weighted mean FEV1; differences between the adjusted means for AM and PM FF dosing versus placebo were 0.077 L (90% confidence interval [CI]: 0.001, 0.152) and 0.105 L (90% CI: 0.029, 0.180), respectively (adjusted mean difference: -0.028 L [90% CI: -0.102, 0.045]). AM or PM doses had comparable incidences of adverse events (AEs; 18/23 versus 18/24, respectively), no serious AEs occurred.

CONCLUSION

AM and PM doses of once-daily FF 100 μg produced comparable improvements in lung function relative to placebo.

Endoscopic repair of cerebrospinal fluid rhinorrhoea

GOAL

The purpose of this review was to look at the success rate of transnasal endoscopic repair of CSF rhinorrhoea and the impact of patient factors, repair techniques and adjuvant treatment.

MATERIAL AND METHODS

A literature search was performed on PubMed, Medline and Cochrane Central databases, independently by two of the authors, of all studies reporting the outcomes of CSF rhinorrhoea repair, published until the 1st June 2014, using keywords Cerebrospinal fluid leak, CSF leak, CSF fistula, CSF leak or fistula repair, endoscopic sinus surgery or ESS complications. Sixty-seven papers were included for the review.

RESULT

The repair of CSF rhinorrhoea has rapidly evolved over the past 30 years. Prior to the advent of the endoscopic approach, craniotomy was used for repairs, which carried a variable success rate and morbidity. More recently, there have been several case series and reports that describe various endoscopic methods and materials for repair, with mean success rate of 90% (range: 60-100%). The most common site of CSF leak is the ethmoid roof/cribriform plate region. Traumatic CSF leak, in particular iatrogenic, is still the most common cause. Imaging with CT and MRI remains the gold standard for localisation of CSF leaks. The sphenoid sinus is the most common location for CSF leak repair failure. Lumbar drains and antibiotics are used as adjuvant therapy to endoscopic repair, but their benefits are not clear; intrathecal fluorescein can be used to aid location of CSF leak, but should be reserved for more complex cases. Further work into graft materials used and adjuvant treatment is needed to make any meaningful conclusions about their efficacy.

CONCLUSION

The literature demonstrates that endoscopic repair of CSF rhinorrhoea is safe and effective, with a very low complication rate. It has almost completely replaced the older open techniques.

Gene conversion between cationic trypsinogen (PRSS1) and the pseudogene trypsinogen 6 (PRSS3P2) in patients with chronic pancreatitis

Mutations of the human cationic trypsinogen gene (PRSS1) are frequently found in association with hereditary pancreatitis. The most frequent variants p.N29I and p.R122H are recognized as disease-causing mutations. Three pseudogene paralogs in the human trypsinogen family, including trypsinogen 6 (PRSS3P2), carry sequence variations in exon 3 that mimic the p.R122H mutation. In routine genetic testing of patients with chronic pancreatitis, we identified in two unrelated individuals similar gene conversion events of 24-71 nucleotides length between exon 3 of the PRSS1 (acceptor) and PRSS3P2 (donor) genes. The converted allele resulted in three nonsynonymous alterations c.343T>A (p.S115T), c.347G>C (p.R116P), and c.365_366delinsAT (p.R122H). Functional analysis of the conversion triple mutant revealed markedly increased autoactivation resulting in high and sustained trypsin activity in the presence of chymotrypsin C. This activation phenotype was identical to that of the p.R122H mutant. In addition, cellular secretion of the triple mutant from transfected HEK 293T cells was increased about twofold and this effect was attributable to mutation p.R116P. Our observations confirm and extend the notion that recombination events between members of the trypsinogen family can generate high-risk PRSS1 alleles. The pathogenic phenotype of the novel conversion is explained by a unique combination of increased trypsinogen activation and secretion.

Novel sporadic and recurrent mutations in KRT5 and KRT14 genes in Polish epidermolysis bullosa simplex patients: further insights into epidemiology and genotype-phenotype correlation

Epidermolysis bullosa simplex (EBS) is a hereditary genodermatosis characterised by trauma-induced intraepidermal blistering of the skin. EBS is mostly caused by mutations in the KRT5 and KRT14 genes. Disease severity partially depends on the affected keratin type and may be modulated by mutation type and location. The aim of our study was to identify the molecular defects in KRT5 and KRT14 in a cohort of 46 Polish and one Belarusian probands with clinical suspicion of EBS and to determine the genotype-phenotype correlation. The group of 47 patients with clinical recognition of EBS was enrolled in the study. We analysed all coding exons of KRT5 and KRT14 using Sanger sequencing. The pathogenic status of novel variants was evaluated using bioinformatical tools, control group analysis (DNA from 100 healthy population-matched subjects) and probands' parents testing. We identified mutations in 80 % of patients and found 29 different mutations, 11 of which were novel and six were found in more than one family. All novel mutations were ascertained as pathogenic. In the majority of cases, the most severe genotype was associated with mutations in highly conserved regions. In some cases, different inheritance mode and clinical significance, than previously reported by others, was observed. We report 11 novel variants and show novel genotype-phenotype correlations. Our data give further insight into the natural history of EBS molecular pathology, epidemiology and mutation origin.

Genetic analysis in inherited metabolic disorders--from diagnosis to treatment. Own experience, current state of knowledge and perspectives

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.

Novel Mutations in the IRF6 Gene on the Background of Known Polymorphisms in Polish Patients with Orofacial Clefting

Objective

To examine the role of the IRF6 mutations in Polish families with Van der Woude syndrome and popliteal pterygium syndrome and to determine the effect of IRF6 single nucleotide polymorphisms (rs7552506, rs2013162, and rs2235375) on cleft lip and/or palate susceptibility.

Design

IRF6 mutation screening was performed by direct sequencing of all coding exons of the gene and their flanking intronic regions. Cosegregation analysis was performed to establish the relation of single nucleotide polymorphisms and cleft lip and/or palate phenotypes.

Patients

We screened the IRF6 gene in eight families with clinical recognition of Van der Woude syndrome and popliteal pterygium syndrome.

Results

In five families we identified pathogenic mutations, all affecting the DNA-binding or the protein-binding domain of IRF6. Two of the mutations were novel—a missense mutation Arg31Thr and a small deletion Trp40Glyfs∗23. In most cases we found also a haplotype of three single nucleotide polymorphisms—rs7552506, rs2013162, and rs2235375. The association of the single nucleotide polymorphisms and cleft lip and/or palate susceptibility has been previously published. The variants did not cosegregate with phenotype in examined families nor did they cosegregate with pathogenic mutations. The single nucleotide polymorphisms were deemed not causative, due to their presence in unaffected family members.

Conclusions

Two novel mutations (Arg31Thr and Trp40Glyfs∗23) in the IRF6 gene were identified to be causative for Van der Woude and popliteal pterygium syndromes. In the present study no association between the single nucleotide polymorphisms rs7552506, rs2013162, and rs2235375 and the cleft lip and/or palate phenotype was found. The hypothesis, whether the haplotype of the three single nucleotide polymorphisms was correlated with IRF6 expression level, demands further investigation.

CHRONIC PANCREATITIS IN A PATIENT WITH THE p.Asn34Ser HOMOZYGOUS SPINK1 MUTATION--OWN EXPERIENCE

Chronic pancreatitis (CP) is characterized by progressive damage to the exocrine and endocrine cell structures and pancreatic ducts with subsequent fibrosis of the organ. Patients with no apparent etiological factor are classified as having idiopathic CP (ICP). Genetic studies indicate the importance of mutations in the serine protease inhibitor, Kazal type 1 gene (SPINK1) in the pathogenesis of CP This report describes a case of a 29-year-old Polish-Vietnamese patient with the p.Asn34Ser (p.N34S) homozygous mutation in the SPINK1 gene. The patient was hospitalized due to pain of average intensity in the epigastric area which occurred for the first time in his life. Imaging examination showed the atrophy of the pancreatic parenchyma with the presence of numerous small calcifications and a single calcified lodgement with a diameter of 22 mm in the distal segment of Wirsung 's duct. Clinical interview did not reveal any obvious etiological pancreatitis risk factors implying the causative role of the p.Asn34Ser homozygous mutation of SPINK1 in this case as proven in our investigation.

Complex interplay between the length and composition of the huntingtin-derived peptides modulates the intracellular behavior of the N-terminal fragments of mutant huntingtin

Diverse subcellular localizations of the huntingtin-containing inclusion bodies are frequently suspected of reflecting crucial divisions between different cellular pathways contributing to the pathophysiology of Huntington's disease. Here, we use a panel of different N-terminal huntingtin fragments overexpressed in transfected neuronal and non-neuronal cells to demonstrate that it is the length of the N-terminal huntingtin fragments rather than a presence of any specific amino acid sequences that determines the ratio between the nuclear and cytoplasmic inclusion bodies. Importantly, the length of those fragments does also seem to strongly influence the folding of the aggregating huntingtin species, as indicated by the apparent differences in their accessibility for different antibodies directed against particular subdomains within the N-terminal part of huntingtin, although these differences do not correlate with the peptides' ability to efficiently aggregate within the cell nucleus. Furthermore, the relatively long huntingtin fragment containing 588 amino acids of the reference sequence shows intracellular behavior that is substantially different from that exhibited by its shorter counterparts (containing either 171, 120, 89 or 64 amino acids), as this rarely aggregating peptide is not only accumulating in cytoplasmic inclusions of slightly different morphology but is also most strongly affected by the FLAG-tagging procedure that unexpectedly induces (or enhances) autophagy-related processes. Together, our results reveal a significant heterogeneity of the huntingtin accumulation patterns that are observed at the cellular level. These patterns are not only strongly dependent on both the length and the amino acid composition of the N-terminal huntingtin peptides but also seem to engage different cellular mechanisms implicated in the pathogenesis of Huntington's disease, including the non-proteasomal degradation of potentially toxic huntingtin forms.

Intrafamilial variability of the primary dystonia DYT6 phenotype caused by p.Cys5Trp mutation in THAP1 gene

Mutations localized in THAP1 gene, locus 18p11.21 have been reported as causative of primary dystonia type 6 (DYT6). Disease which is characterized mainly by focal dystonia, frequently involving the craniocervical region, however associated also with early-onset generalized dystonia and spasmodic dysphonia. Here we report a novel mutation in the THAP1 gene identified in a Polish family with DYT6 phenotype - the c.15C>G substitution in exon 1 introducing the missense mutation p.Cys5Trp within the N-terminal THAP domain. The mutation was described in two generations, in patients showing a broad spectrum of focal and generalized dystonia symptoms of variable onset. Our results indicate that certain mutations in the THAP1 gene may lead to primary dystonia with remarkable intrafamilial clinical variability.

[Non-invasive genetic prenatal diagnosis. Analysis of nucleic acids of foetal origin present in maternal vascular system]

Prenatal diagnosis is an important element of health care in pregnant women. Until now, prenatal testing of genetically determined diseases was invasive. Identification in maternal plasma of cell-free fetal nucleic acids (cffNA) has created new opportunities, and gave rise to genetic non-invasive prenatal diagnosis (NIPD). They are three leading trends in NIPD, depending on the clinical application: analysis of hereditary diseases, analysis of aneuploidy and study of maternal-fetal conflict. In case of hereditary diseases, application of NIPD is limited to autosomal dominant disorders where the mutation is carried on the paternal allelle. It refers to problems with distinguish fetal derived cell-free DNA from maternal cell-free DNA. The important issue for using NIPD techniques in practice is to develop appropriate law regulation. This is of particular importance in the non-medical applications, when the aim of testing could be e.g. selection of fetuses. The development of effective methods for the analysis of free fetal DNA present in the mother's bloodstream is a matter of few years and show the progress made in the fields of molecular biology and medicine. It seems that non-invasive testing for a wider range of genetic disorders is a only a question of time.

[Cystic fibrosis emerging therapies]

Cystic fibrosis is one of the most common recessively inherited monogenic disorders in the Caucasian population. The disease develops when pathogenic mutations of the CFTR gene, encoding a transmembrane conductance regulator, are present in both alleles. Cystic fibrosis is a multi-organ disease with heterozygous clinical course. High mortality of the disease is mainly due to progressive and irreversible changes in the lungs, leading to respiratory failure. Therefore, chronic obstructive pulmonary disease is the primary target in the search for effective therapeutic solutions. In recent years there has been a significant progress in the research on early diagnosis and treatment of cystic fibrosis. The newest strategies focus not only on the main symptoms of pulmonary disease (inflammation caused by bacterial infection and obstruction due to thickened mucus), but also on the correction of the cystic fibrosis cause - defective CFTR gene and its protein product. Therapeutics like VX-770 and PTC124, intended for patients with a specific genotype, have already emerged on the U.S. and European medical market. They modulate the defective CFTR protein function or act on the level of abnormal CFTR mRNA, respectively. At the same time scientists develop new solutions in the field of somatic gene therapy in order to increase the efficiency of corrected CFTR delivery to the respiratory tract cells and to maintain its expression in the target cells. In this review we discuss the progress achieved in the development of therapy that is at the stage of both preclinical and clinical phases.

Novel A18T and pA29S substitutions in α-synuclein may be associated with sporadic Parkinson's disease

OBJECTIVE

Mutations in the α-synuclein-encoding gene SNCA are considered as a rare cause of Parkinson's disease (PD). Our objective was to examine the frequency of the SNCA point mutations among PD patients of Polish origin.

METHODS

Detection of the known SNCA point mutations A30P (c.88G>C), E46K (c.136G>A) and A53T (c.157A>T) was performed either using the Sequenom MassArray iPLEX platform or by direct sequencing of the SNCA exons 2 and 3. As the two novel substitutions A18T (c.52G>A) and A29S (c.85G>T) were identified, their frequency in a control population of Polish origin was assessed and in silico analysis performed to investigate the potential impact on protein structure and function.

RESULTS

We did not observe the previously reported point mutations in the SNCA gene in our 629 PD patients; however, two novel potentially pathogenic substitutions A18T and A29S were identified. Each variant was observed in a single patient presenting with a typical late-onset sporadic PD phenotype. Although neither variant was observed in control subjects and in silico protein analysis predicts a damaging effect for A18T and pA29S substitutions, the lack of family history brings into question the true pathogenicity of these rare variants.

CONCLUSIONS

Larger population based studies are needed to determine the pathogenicity of the A18T and A29S substitutions. Our findings highlight the possible role of rare variants contributing to disease risk and may support further screening of the SNCA gene in sporadic PD patients from different populations.

The spectrum of PLP1 gene mutations in patients with the classical form of the Pelizaeus-Merzbacher disease

The Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive hypomyelination disorder caused by mutations of the proteolipid protein1 gene (PLP1). There is a spectrum of PLP1-related disorders from very severe connatal PMD, through classical PMD to mild spastic paraplegia type 2 (SPG2), with some correlation between the type of mutation and the phenotype. In general, missense mutations give rise to more severe forms of the disease, deletions and null mutations to mild PMD and SPG2. The most common variations, duplications, result in the classical-intermediate form of PMD.

THE AIM

To report the analysis of mutations in the PLP1 gene and phenotype di!erences in ten male patients diagnosed with PMD. Although they had different types of PLP1 mutations (duplications, missense and nonsense mutations), all of them were clinically classi"ed with the classical form of PMD (clPMD).

MATERIAL AND METHODS

The subjects of analysis were ten male patients aged 1.5 to 21 years who were diagnosed with PMD. All patients developed the "rst clinical symptoms between 1 an 8 months of age and showed developmental delay, mainly in motor skills. All were classified with the classical form of the disease, according to international clinical criteria and the electrophysiological and brain MRI criteria of hypomyelination. The molecular analysis of the PLP1 gene involved dosage analysis and direct sequencing of all exons and promotor region of the gene.

RESULTS

The clinical diagnosis of PMD was con"rmed for all subjects by molecular analysis of the PLP1gene. Although all had the classical form of PMD, it was caused by mutations of di!erent types: duplications of the entire gene, missense and nonsense mutations.

CONCLUSIONS

Our clinical and molecular "ndings showed that the phenotypic spectrum resulting from PLP1 mutations seems to be broader in patients with the PLP1 gene duplication compared to patients with both nonsense and missense mutation. Nevertheless, apart from the type of mutation, all our patients’ clinical manifestation falls into the category of the classical form of PMD according to international criteria. Obviously the type of mutations, but also other unidentified factors may a!ect the clinical course of PMD.The Pelizaeus-Merzbacher disease (PMD) is a rare X-linked recessive hypomyelination disorder caused by mutations of the proteolipid protein 1 gene (PLP1). There is a spectrum of PLP1-related disorders from very severe connatal PMD, through classical PMD to mild spastic paraplegia type 2 (SPG2), with some correlation between the type of mutation and the phenotype. In general, missense mutations give rise to more severe forms of the disease, deletions and null mutations to mild PMD and SPG2. The most common variations, duplications, result in the classical-intermediate form of PMD.

THE AIM

To report the analysis of mutations in the PLP1 gene and phenotype differences in ten male patients diagnosed with PMD. Although they had di!erent types of PLP1 mutations (duplications, missense and nonsense mutations), all of them were clinically classi"ed with the classical form of PMD (clPMD).

MATERIAL AND METHODS

The subjects of analysis were ten male patients aged 1.5 to 21 years who were diagnosed with PMD. All patients developed the "rst clinical symptoms between 1 an 8 months of age and showed developmental delay, mainly in motor skills. All were classified with the classical form of the disease, according to international clinical criteria and the electrophysiological and brain MRI criteria of hypomyelination. The molecular analysis of the PLP1 gene involved dosage analysis and direct sequencing of all exons and promotor region of the gene.

RESULTS

The clinical diagnosis of PMD was con"rmed for all subjects by molecular analysis of the PLP1 gene. Although all had the classical form of PMD, it was caused by mutations of di!erent types: duplications of the entire gene, missense and nonsense mutations.

CONCLUSIONS

Our clinical and molecular findings showed that the phenotypic spectrum resulting from PLP1 mutations seems to be broader in patients with the PLP1 gene duplication compared to patients with both nonsense and missense mutation. Nevertheless, apart from the type of mutation, all our patients' clinical manifestation falls into the category of the classical form of PMD according to international criteria. Obviously the type of mutations, but also other unidentified factors may a!ect the clinical course of PMD.

Mutations in the PLP1 gene residue p. Gly198 as the molecular basis of Pelizeaus-Merzbacher phenotype

Pelizaeus-Merzbacher disease (PMD) and spastic paraplegia type 2 (SPG2) are rare X-linked allelic disorders caused by mutations in the PLP1 gene, encoding the main component of myelin, proteolipid protein 1 (PLP1). Various types of mutations, acting through different molecular mechanism, cause the diseases. Duplications of variable size at Xq22.2, containing the entire PLP1, are responsible for more than 50% of PMD cases. Other causes of PMD include point mutations, gene deletions and triplications. There is a spectrum of PLP1-related disorders with some correlation between the type of mutation and phenotype. Generally the missense mutations cause the more severe forms of the disease, the most common PLP1 duplications, result in the classical PMD whereas deletions and null mutations in mild form of PMD and SPG2. We present a patient with c.593G>A substitution in the exon 4 of the PLP1 gene causing a novel missense mutation p.Gly198Asp, finally diagnosed as PMD but showing an atypical MRI picture.

The COL7A1 mutation database

Dystrophic Epidermolysis Bullosa (DEB) is a genetic disease caused by mutations in the COL7A1 gene that is inherited in the autosomal dominant or recessive mode. We have developed a curated, freely accessible COL7A1 specific database (http://www.col7.info), which contains more than 730 reported and unpublished sequence variants of the gene. Molecular defects are reported according to HGVS recommendation. The clinical description module is provided with an advanced search tool together with a CSV (comm. separated values) data format download option. This compilation of COL7A1 data and nomenclature is aimed at assisting molecular and clinical geneticists to enhance the collaboration between researchers worldwide.