ABSTRACT
BACKGROUND & AIMS: Constitutional mismatch repair deficiency (CMMRD) is a rare recessive childhood cancer predisposition syndrome caused by germline mismatch repair variants. Constitutional microsatellite instability (cMSI) is a CMMRD diagnostic hallmark and may associate with cancer risk. We quantified cMSI in a large CMMRD patient cohort to explore genotype-phenotype correlations using novel MSI markers selected for instability in blood. METHODS: Three CMMRD, 1 Lynch syndrome, and 2 control blood samples were genome sequenced to >120× depth. A pilot cohort of 8 CMMRD and 38 control blood samples and a blinded cohort of 56 CMMRD, 8 suspected CMMRD, 40 Lynch syndrome, and 43 control blood samples were amplicon sequenced to 5000× depth. Sample cMSI score was calculated using a published method comparing microsatellite reference allele frequencies with 80 controls. RESULTS: Thirty-two mononucleotide repeats were selected from blood genome and pilot amplicon sequencing data. cMSI scoring using these MSI markers achieved 100% sensitivity (95% CI, 93.6%-100.0%) and specificity (95% CI 97.9%-100.0%), was reproducible, and was superior to an established tumor MSI marker panel. Lower cMSI scores were found in patients with CMMRD with MSH6 deficiency and patients with at least 1 mismatch repair missense variant, and patients with biallelic truncating/copy number variants had higher scores. cMSI score did not correlate with age at first tumor. CONCLUSIONS: We present an inexpensive and scalable cMSI assay that enhances CMMRD detection relative to existing methods. cMSI score is associated with mismatch repair genotype but not phenotype, suggesting it is not a useful predictor of cancer risk.
Subject(s)
Brain Neoplasms , Colorectal Neoplasms, Hereditary Nonpolyposis , Colorectal Neoplasms , Neoplastic Syndromes, Hereditary , Humans , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Microsatellite Instability , Neoplastic Syndromes, Hereditary/diagnosis , Neoplastic Syndromes, Hereditary/genetics , Colorectal Neoplasms/genetics , Colorectal Neoplasms/diagnosis , Brain Neoplasms/diagnosis , Genotype , DNA Mismatch Repair/genetics , Mismatch Repair Endonuclease PMS2/geneticsABSTRACT
Plexiform neurofibromas are the hallmark of neurofibromatosis type 1 (NF1) and significantly contribute to the overall burden of disease. While surgical excision has long been the only available therapy, the MEK inhibitor (MEKi) selumetinib has been approved as a non-surgical treatment option for these tumors in 2020 (USA) and 2021 (Europe), respectively. However, selumetinib will result in tumor shrinkage only after several months of therapy and might not prevent malignant transformation of a plexiform neurofibroma that occurs with a frequency of 10-15%. Here, we demonstrate that surgical excision might be the therapy of choice in some plexiform neurofibromas despite the availability of MEKi therapy.
Subject(s)
Neurofibroma, Plexiform , Neurofibroma , Neurofibromatosis 1 , Humans , Neurofibroma, Plexiform/surgery , Neurofibroma, Plexiform/pathology , Neurofibroma/surgery , Neurofibroma/pathology , Neurofibromatosis 1/complications , Neurofibromatosis 1/surgery , Neurofibromatosis 1/pathology , EuropeABSTRACT
Neurofibromatosis type-1 (NF1)-associated plexiform neurofibromas (PN) are peripheral nerve sheath tumors that can significantly affect the quality of life. Until recently, surgery was the only treatment for these tumors. However, in most cases, surgery cannot achieve complete tumor removal and carries a high risk of postoperative deficits. Therefore, the recent approval of the MEK inhibitor selumetinib for the treatment of NF1-associated PN provides a long-awaited novel therapeutic option. Here, we report our experience with MEK inhibitor treatment in 12 pediatric NF1 patients with inoperable symptomatic PN. Eight patients received trametinib (median therapy duration 12.13 months and range 4-29 months), and four patients received selumetinib (median therapy duration 6.25 months and range 4-11 months). Volumetric magnetic resonance imaging (MRI) after 6 months of treatment was available for seven trametinib patients (median tumor volume reduction of 26.5% and range 11.3-55.7%) and two selumetinib patients (21.3% tumor volume reduction in one patient and +3% tumor volume change in the other one). All patients reported clinical benefits such as improved range of motion or reduced disfigurement. Therapy-related adverse events occurred in 58.3% of patients and mainly consisted of skin toxicity, paronychia, and gastrointestinal symptoms. Two patients discontinued trametinib treatment after 14 and 29 months when severe skin toxicity occurred and no further reduction of tumor size was observed. In one patient, discontinuation of therapy resulted in a 27.2% tumor volume increase as demonstrated on volumetric MRI 6 months later. Our data show that MEK inhibition is a novel therapeutic approach for inoperable PN with promising results and a manageable safety profile.
Subject(s)
Neurofibroma, Plexiform , Neurofibromatosis 1 , Child , Humans , Mitogen-Activated Protein Kinase Kinases/therapeutic use , Neurofibroma, Plexiform/diagnostic imaging , Neurofibroma, Plexiform/drug therapy , Neurofibromatosis 1/diagnostic imaging , Neurofibromatosis 1/drug therapy , Protein Kinase Inhibitors/adverse effects , Quality of LifeABSTRACT
INTRODUCTION: Lynch syndrome (LS) and constitutional mismatch repair deficiency (CMMRD) are hereditary cancer syndromes associated with mismatch repair (MMR) deficiency. Tumours show microsatellite instability (MSI), also reported at low levels in non-neoplastic tissues. Our aim was to evaluate the performance of high-sensitivity MSI (hs-MSI) assessment for the identification of LS and CMMRD in non-neoplastic tissues. MATERIALS AND METHODS: Blood DNA samples from 131 individuals were grouped into three cohorts: baseline (22 controls), training (11 CMMRD, 48 LS and 15 controls) and validation (18 CMMRD and 18 controls). Custom next generation sequencing panel and bioinformatics pipeline were used to detect insertions and deletions in microsatellite markers. An hs-MSI score was calculated representing the percentage of unstable markers. RESULTS: The hs-MSI score was significantly higher in CMMRD blood samples when compared with controls in the training cohort (p<0.001). This finding was confirmed in the validation set, reaching 100% specificity and sensitivity. Higher hs-MSI scores were detected in biallelic MSH2 carriers (n=5) compared with MSH6 carriers (n=15). The hs-MSI analysis did not detect a difference between LS and control blood samples (p=0.564). CONCLUSIONS: The hs-MSI approach is a valuable tool for CMMRD diagnosis, especially in suspected patients harbouring MMR variants of unknown significance or non-detected biallelic germline mutations.
Subject(s)
Brain Neoplasms/genetics , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Colorectal Neoplasms/genetics , DNA-Binding Proteins/genetics , Microsatellite Instability , MutS Homolog 2 Protein/genetics , Neoplastic Syndromes, Hereditary/genetics , Adolescent , Adult , Brain Neoplasms/blood , Brain Neoplasms/pathology , Child , Child, Preschool , Colorectal Neoplasms/blood , Colorectal Neoplasms/pathology , Colorectal Neoplasms, Hereditary Nonpolyposis/blood , Colorectal Neoplasms, Hereditary Nonpolyposis/pathology , DNA Mismatch Repair/genetics , Female , Germ-Line Mutation/genetics , Heterozygote , High-Throughput Nucleotide Sequencing , Humans , Infant , Male , Neoplastic Syndromes, Hereditary/blood , Neoplastic Syndromes, Hereditary/pathology , Young AdultABSTRACT
PURPOSE: An estimated 5-11% of patients with neurofibromatosis type 1 (NF1) harbour NF1 microdeletions encompassing the NF1 gene and its flanking regions. The purpose of this study was to evaluate the clinical phenotype in children and adolescents with NF1 microdeletions. METHODS: We retrospectively analysed 30 children and adolescents with NF1 microdeletions pertaining to externally visible neurofibromas. The internal tumour load was determined by volumetry of whole-body magnetic resonance imaging (MRI) in 20 children and adolescents with NF1 microdeletions. Furthermore, the prevalence of global developmental delay, autism spectrum disorder and attention deficit hyperactivity disorder (ADHD) were evaluated. RESULTS: Children and adolescents with NF1 microdeletions had significantly more often cutaneous, subcutaneous and externally visible plexiform neurofibromas than age-matched patients with intragenic NF1 mutations. Internal neurofibromas were detected in all 20 children and adolescents with NF1 microdeletions analysed by whole-body MRI. By contrast, only 17 (61%) of 28 age-matched NF1 patients without microdeletions had internal tumours. The total internal tumour load was significantly higher in NF1 microdeletion patients than in NF1 patients without microdeletions. Global developmental delay was observed in 28 (93%) of 30 children with NF1 microdeletions investigated. The mean full-scale intelligence quotient in our patient group was 77.7 which is significantly lower than that of patients with intragenic NF1 mutations. ADHD was diagnosed in 15 (88%) of 17 children and adolescents with NF1 microdeletion. Furthermore, 17 (71%) of the 24 patients investigated had T-scores ≥ 60 up to 75, indicative of mild to moderate autistic symptoms, which are consequently significantly more frequent in patients with NF1 microdeletions than in the general NF1 population. Also, the mean total T-score was significantly higher in patients with NF1 microdeletions than in the general NF1 population. CONCLUSION: Our findings indicate that already at a very young age, NF1 microdeletions patients frequently exhibit a severe disease manifestation which requires specialized long-term clinical care.
Subject(s)
Autism Spectrum Disorder , Neurofibromatosis 1 , Adolescent , Child , Humans , Magnetic Resonance Imaging , Neurofibromatosis 1/genetics , Retrospective Studies , Whole Body ImagingABSTRACT
Constitutional mismatch repair deficiency (CMMRD) is caused by germline pathogenic variants in both alleles of a mismatch repair gene. Patients have an exceptionally high risk of numerous pediatric malignancies and benefit from surveillance and adjusted treatment. The diversity of its manifestation, and ambiguous genotyping results, particularly from PMS2, can complicate diagnosis and preclude timely patient management. Assessment of low-level microsatellite instability in nonneoplastic tissues can detect CMMRD, but current techniques are laborious or of limited sensitivity. Here, we present a simple, scalable CMMRD diagnostic assay. It uses sequencing and molecular barcodes to detect low-frequency microsatellite variants in peripheral blood leukocytes and classifies samples using variant frequencies. We tested 30 samples from 26 genetically-confirmed CMMRD patients, and samples from 94 controls and 40 Lynch syndrome patients. All samples were correctly classified, except one from a CMMRD patient recovering from aplasia. However, additional samples from this same patient tested positive for CMMRD. The assay also confirmed CMMRD in six suspected patients. The assay is suitable for both rapid CMMRD diagnosis within clinical decision windows and scalable screening of at-risk populations. Its deployment will improve patient care, and better define the prevalence and phenotype of this likely underreported cancer syndrome.
Subject(s)
Brain Neoplasms/diagnosis , Brain Neoplasms/genetics , Colorectal Neoplasms/diagnosis , Colorectal Neoplasms/genetics , DNA Mismatch Repair , Genetic Association Studies , Genetic Predisposition to Disease , Leukocytes/metabolism , Microsatellite Instability , Neoplastic Syndromes, Hereditary/diagnosis , Neoplastic Syndromes, Hereditary/genetics , Alleles , Genetic Association Studies/methods , Germ-Line Mutation , Humans , Microsatellite RepeatsABSTRACT
Plexiform neurofibromas are congenital peripheral nerve sheath tumors characteristic of neurofibromatosis type 1 (NF1)-a frequent neurocutaneous disorder caused by mutations of the NF1 tumor suppressor gene. Since plexiform neurofibromas are a major cause of the burden of disease and may also progress to malignancy, many efforts have been undertaken to find a cure for these tumors. However, neither surgery nor medication has so far produced a breakthrough therapeutic success. Recently, a clinical phase I study reported significant shrinkage of plexiform neurofibromas following treatment with the MEK inhibitor selumetinib. Here, we report an 11-year-old NF1 patient with a large plexiform neurofibroma of the neck that had led to a sharp-angled kinking of the cervical spine and subsequent myelopathy. Although surgical stabilization of the cervical vertebral column was urgently recommended, the vertebral column was inaccessible due to extensive tumor growth. In this situation, treatment with the MEK inhibitor trametinib was initiated which resulted in a 22% reduction in tumor volume after 6 months of therapy and finally enabled surgery. These data show that MEK inhibitors may not lead to complete disappearance of NF1-associated plexiform neurofibromas but can be an essential step in a multimodal therapeutic approach for these tumors. The course of our patient suggests that MEK inhibitors are likely to play a significant role in providing a cure for one of the most devastating manifestations of NF1.
Subject(s)
Antineoplastic Agents/therapeutic use , Cervical Cord/surgery , Neurofibroma, Plexiform/drug therapy , Protein Kinase Inhibitors/therapeutic use , Pyridones/therapeutic use , Pyrimidinones/therapeutic use , Child , Female , Humans , Neurofibroma, Plexiform/complications , Neurofibromatosis 1/complications , Neurofibromin 1/genetics , Treatment OutcomeABSTRACT
Cabezas type of X-linked syndromic intellectual disability (MRXSC; MIM300354) is a rare X-linked recessive intellectual disability characterized primarily by intellectual disability, short stature, hypogonadism, and gait abnormalities. It is caused by a wide spectrum of hemizygous variants in CUL4B. In a 10-year-old boy with an exceptional leukoencephalopathy pattern, we identified a new missense variant p.Leu329Gln in CUL4B using "Mendeliome" sequencing. However, his phenotype does not include the severe characteristics currently known for MRXSC. We discuss the divergent phenotype and propose a potential connection between the different CUL4B variants and corresponding phenotypes in the context of the current literature as well as 3D homology modeling.
Subject(s)
Cullin Proteins/genetics , Leukoencephalopathies/genetics , Mutation, Missense , Child , Humans , Leukoencephalopathies/pathology , Male , Phenotype , PrognosisABSTRACT
Diagnosis of neurofibromatosis type 1 (NF1) can be established when at least two out of seven defined clinical findings are present. However, a definite clinical diagnosis may be challenging, especially in young children. Therefore, we tried to identify additional clinical signs suggestive of NF1. We observed that nevi anemici (NA) occur with increased frequency in NF1 patients. To establish NA as an additional diagnostic criterion for NF1 we evaluated their exact frequency in children potentially affected by NF1. During a 6-month period we examined 100 NF1 patients and documented patients' age and sex as well as presence, location, and characteristic features of NA. We were able to show that NA are present in 28% of NF1 patients, which is well above the 5% prevalence of NA in the general population. It is not known why NA appear with increased frequency in NF1. We hypothesize that an imbalance between α- and ß-adrenergic receptors, resulting in increased α-adrenergic vasoconstriction might be the underlying cause of NF1-associated NA. Based on our own observations and previously published studies, we propose that NA in children with suspected NF1 might facilitate definite diagnosis and improve clinical management.
Subject(s)
Neurofibromatosis 1/epidemiology , Nevus/epidemiology , Skin Neoplasms/epidemiology , Adolescent , Age Distribution , Child , Child, Preschool , Cohort Studies , Female , Humans , Infant , Male , Neurofibromatosis 1/diagnosis , Prospective Studies , Sex Distribution , Young AdultABSTRACT
BACKGROUND/AIM: Neurofibromatosis type 1 (NF) is an autosomal dominant hereditary disease. The cardinal clinical findings include characteristic skeletal alterations. Difficulties in diagnosis and therapy can arise if an individual has further illnesses. CASE REPORT: This is a case report of a 16-year-old patient affected by NF1. She also suffered from Alagille syndrome and the consequences of fetal alcohol exposure. The patient's facial phenotype showed findings that could be assigned to one or more of the known diseases. The patient was referred for treating a cherubism-like recurrent central giant cell granuloma (CGCG) of the jaw. The patient developed bilateral, multilocular non-ossifying fibromas (NOF) of the long bones of the lower extremity. Treatment of the skeletal lesions consisted of local curettage. While NOF regressed after surgery, the CGCG of the jaw remained largely unchanged. Extensive genetic tests confirmed a previously unknown germline mutation in the JAG1 gene, the germline mutation of the NF1 gene, and the somatic mutation in the NF1 gene in the diffuse plexiform neurofibroma, but not in the CGCG. CONCLUSION: Assigning facial findings to a defined syndrome is ambiguous in many cases and especially difficult in patients who have multiple diseases that can affect the facial phenotype. Surgical therapy should be adapted to the individual findings.
Subject(s)
Alagille Syndrome , Cherubism , Neurofibromatosis 1 , Adolescent , Female , Humans , Lower Extremity , Neurofibromatosis 1/complications , Neurofibromatosis 1/diagnosis , Neurofibromatosis 1/genetics , PhenotypeABSTRACT
Neurofibromatosis type 1 (NF1) is a common autosomal dominant disorder caused by heterozygotic inactivation of the NF1 tumor suppressor gene at 17q11.2. The associated phenotypes are highly variable, and modifying genes have been proposed to explain at least in part the intriguing expressivity. Given that haploinsufficiency of the NF1 gene product neurofibromin is responsible for some of the clinical manifestations, variations in expression of the wildtype NF1 allele might modify the phenotype. We therefore investigated epigenetic molecular modifications that could result in variable expression of the normal NF1 allele. To exclude confounding by DNA sequence variations, we analyzed monozygotic twin pairs with NF1 who presented with several discordant features. We fine-mapped the methylation pattern of a nearly 1 kb NF1 promoter region in lymphocytes of 8 twin pairs. All twin pairs showed significant intra-pair differences in methylation, especially of specific promoter subregions such as 5'UTR, exon 1 and intron 1 (+7 to +622), transcription factor binding sites and promoter elements like NF1HCS. Furthermore, we detected significant intra-pair differences in cytosine methylation for the region from -249 to -234 with regard to discordance for optic glioma with a higher grade of methylation in glioma cases. In conclusion, our findings of epigenetic differences of the NF1 promoter in leukocytes within mono zygotic twin pairs may serve as a proof of principle for other tissues. The results point towards a role of methylation patterns of the normal NF1 allele for expression differences and for modification of the NF1 phenotype.
Subject(s)
DNA Methylation , Diseases in Twins/genetics , Neurofibromatosis 1/genetics , Neurofibromin 1/genetics , Twins, Monozygotic/genetics , Untranslated Regions/genetics , Adolescent , Adult , Child , Epigenomics , Exons/genetics , Female , Haploinsufficiency , Humans , Introns/genetics , Lymphocytes/metabolism , Lymphocytes/pathology , Male , Optic Nerve Glioma/genetics , Promoter Regions, Genetic/geneticsABSTRACT
Medulloblastoma is the most frequent malignant brain tumor in childhood. This highly malignant neoplasm occurs usually before 10 years of age and more frequently in boys. The 5-year event-free survival rate for high-risk medulloblastoma is low at 62% despite a multimodal therapy including surgical resection, radiation therapy and chemotherapy. We report the case of a boy, who was born to consanguineous parents. Prominently, he had multiple café-au-lait spots. At the age of 3 years he was diagnosed with a high-risk metastatic medulloblastoma. The patient died only 11 months after diagnosis of a fulminant relapse presenting as meningeal and spinal dissemination. Whole-exome sequencing of germline DNA was employed to detect the underlying mutation for this putative cancer syndrome presenting with the combination of medulloblastoma and skin alterations. After screening all possible homozygous gene SNVs, we identified a mutation of SON, an essential protein in cell cycle regulation and cell proliferation, as the most likely genetic cause.
Subject(s)
Cafe-au-Lait Spots/genetics , Cerebellar Neoplasms/genetics , DNA-Binding Proteins/genetics , Medulloblastoma/genetics , Minor Histocompatibility Antigens/genetics , Child, Preschool , Consanguinity , Fatal Outcome , Humans , Male , Pedigree , Point Mutation , SyndromeABSTRACT
Immunoglobulin class-switch recombination (CSR) and somatic hypermutations (SHMs) are prerequisites for antibody and immunoglobulin receptor maturation and adaptive immune diversity. The mismatch repair (MMR) machinery, consisting of homologs of MutSα, MutLα, and MutSß (MSH2/MSH6, MLH1/PMS2, and MSH2/MSH3, respectively) and other proteins, is involved in CSR, primarily acting as a backup for nonhomologous end-joining repair of activation-induced cytidine deaminase-induced DNA mismatches and, furthermore, in addition to error-prone polymerases, in the repair of SHM-induced DNA breaks. A varying degree of antibody formation defect, from IgA or selective IgG subclass deficiency to common variable immunodeficiency and hyper-IgM syndrome, has been detected in a small number of patients with constitutional mismatch repair deficiency (CMMRD) due to biallelic loss-of-function mutations in one of the MMR genes (PMS2, MSH6, MLH1, or MSH2). To elucidate the clinical relevance of a presumed primary immunodeficiency (PID) in CMMRD, we systematically collected clinical history and laboratory data of a cohort of 15 consecutive, unrelated patients (10 not previously reported) with homozygous/compound heterozygous mutations in PMS2 (n = 8), MSH6 (n = 5), and MLH1 (n = 2), most of whom manifested with typical malignancies during childhood. Detailed descriptions of their genotypes, phenotypes, and family histories are provided. Importantly, none of the patients showed any clinical warning signs of PID (infections, immune dysregulation, inflammation, failure to thrive, etc.). Furthermore, we could not detect uniform or specific patterns of laboratory abnormalities. The concentration of IgM was increased in 3 out of 12, reduced in 3 out of 12, and normal in 6 out of 12 patients, while concentrations of IgG and IgG subclasses, except IgG4, and of IgA, and specific antibody formation were normal in most. Class-switched B memory cells were reduced in 5 out of 12 patients, and in 9 out of 12 also the CD38hiIgM- plasmablasts were reduced. Furthermore, results of next generation sequencing-based analyses of antigen-selected B-cell receptor rearrangements showed a significantly reduced frequency of SHM and an increased number of rearranged immunoglobulin heavy chain (IGH) transcripts that use IGHG3, IGHG1, and IGHA1 subclasses. T cell subsets and receptor repertoires were unaffected. Together, neither clinical nor routine immunological laboratory parameters were consistently suggestive of PID in these CMMRD patients, but previously shown abnormalities in SHM and rearranged heavy chain transcripts were confirmed.
ABSTRACT
The clinical manifestations of cerebral malformations are complex and vary from mild retardation to massive disabilities. A review of the literature suggests that the developmental outcome in these patients depends on the extension, location, and combination of such anomalies. However, the authors present the encouraging clinical course of a girl with a complex cerebral malformation. Despite the severe imaging findings, at the present age of 34 months, the patient developed only a mild psychomotor retardation. This case illustrates that the morphological classification of cerebral malformations does not allow one to predict with certainty whether a child will develop impaired motor and/or higher cognitive functions.
Subject(s)
Brain Diseases/pathology , Brain Diseases/physiopathology , Brain/abnormalities , Brain/pathology , Child, Preschool , Female , Humans , Magnetic Resonance Imaging , Review Literature as TopicABSTRACT
Neurofibromatosis type 1 (NF1) is mainly characterized by the occurrence of benign peripheral nerve sheath tumors or neurofibromas. Thorough investigation of the somatic mutation spectrum has thus far been hampered by the large size of the NF1 gene and the considerable proportion of NF1 heterozygous cells within the tumors. We developed an improved somatic mutation detection strategy on cultured Schwann cells derived from neurofibromas and investigated 38 tumors from nine NF1 patients. Twenty-nine somatic NF1 lesions were detected which represents the highest NF1 somatic mutation detection rate described so far (76%). Furthermore, our data strongly suggest that the acquired second hit underlies reduced NF1 expression in Schwann cell cultures. Together, these data clearly illustrate that two inactivating NF1 mutations, in a subpopulation of the Schwann cells, are required for neurofibroma formation in NF1 tumorigenesis. The observed somatic mutation spectrum shows that intragenic NF1 mutations (26/29) are most prevalent, particularly frameshift mutations (12/29, 41%). We hypothesize that this mutation signature might reflect slightly reduced DNA repair efficiency as a trigger for NF1 somatic inactivation preceding tumorigenesis. Joint analysis of the current and previously published NF1 mutation data revealed a significant difference in the somatic mutation spectrum in patients with a NF1 microdeletion vs. non-microdeletion patients with respect to the prevalence of loss of heterozygosity events (0/15 vs. 41/81). Differences in somatic inactivation mechanism might therefore exist between NF1 microdeletion patients and the general NF1 population.
Subject(s)
Mutation/genetics , Neurofibromin 1/genetics , Schwann Cells/metabolism , Adaptor Proteins, Signal Transducing , Carrier Proteins/genetics , DNA Mutational Analysis/methods , DNA Repair/genetics , DNA-Binding Proteins/genetics , Germ-Line Mutation/genetics , Humans , Loss of Heterozygosity , Microsatellite Repeats/genetics , MutL Protein Homolog 1 , MutS Homolog 2 Protein/genetics , Neurofibroma/genetics , Neurofibroma/pathology , Neurofibromatosis 1/genetics , Neurofibromatosis 1/pathology , Nuclear Proteins/genetics , Polymerase Chain Reaction , RNA, Messenger/genetics , RNA, Messenger/metabolism , Sequence Deletion , Tumor Cells, CulturedABSTRACT
Benign tumors of the peripheral nerve sheath, termed neurofibromas, are the hallmark feature of neurofibromatosis type 1 (NF1). These tumors can result in hypertrophy of a limb or another anatomic region. Hemifacial hypertrophy due to an underlying neurofibroma is a typical manifestation of NF1 in young children although the overall frequency of facial involvement is low. We retrospectively studied all patients, which were referred to our outpatient clinic because of hemihypertrophy or swelling of the face for initially unknown reason with a final diagnosis of NF1. A total number of six patients were identified. Clinical and radiological characteristics of these patients were analyzed. In all patients, diagnosis of NF1 could be established based on the typical clinical criteria. However, despite other typical NF1-associated features (e.g. multiple café-au-lait spots) diagnosis of a plexiform neurofibroma as underlying cause for the hemifacial hypertrophy was significantly delayed in all patients. MRI scans were misinterpreted in all of the cases as lymphangioma because plexiform neurofibromas can resemble mesenchymal tumors or lymphangiomas. NF1 has to be considered in the differential diagnosis of hemifacial hypertrophy. A thorough clinical examination of affected patients should focus on typical disease-defining features. Early diagnosis of NF1 can prevent unnecessary treatment at least in some patients.
Subject(s)
Facial Hemiatrophy/pathology , Neurofibroma, Plexiform/diagnosis , Neurofibromatosis 1/diagnosis , Cheek/pathology , Child, Preschool , Facial Hemiatrophy/etiology , Female , Humans , Magnetic Resonance Imaging/methods , Male , Neurofibroma, Plexiform/complications , Retrospective StudiesABSTRACT
INTRODUCTION: Primary pseudotumor cerebri (PTC) in childhood is a rare but important differential diagnosis in children presenting with papilledema. It is defined as elevated cerebrospinal fluid (CSF) pressure of more than 20 cm H(2)O, normal CSF composition, and exclusion of underlying structural or systemic causes. Visual loss is a serious complication, which requires careful monitoring and management. PATIENTS AND METHODS: We conducted a retrospective chart review of 12 patients with primary PTC. The mean age at presentation was 8212 years, and there was a male-to-female ratio of 7:5. The aim of this study was to investigate the clinical features of primary PTC in children, and to highlight the different treatment options in normalizing intracranial pressure in these patients. RESULTS: In the majority of cases, children presented with headache. Four patients had no obvious symptoms and papilledema was found on routine eye examination. Obesity was uncommon and there was no distinct sex predilection. Acetazolamide was our drug of choice for the initial treatment. Furosemide and prednisone were used as second-line agents. Treatment was gradually decreased after resolution of the papilledema with exception of the two youngest children, who remained symptomatic. One child underwent ventricular-peritoneal shunting. DISCUSSION: The treatment goals of PTC are the relief of symptoms, and preservation of visual function. Acetazolamide is an effective first-line method of lowering raised intracranial pressure. In our study group especially the young children were difficult to treat. This might indicate an age-related difference in the etiology of PTC. When medical treatment remains ineffective and visual function deteriorates, surgical treatment should be considered.
Subject(s)
Papilledema/diagnosis , Pseudotumor Cerebri/diagnosis , Adolescent , Child , Child, Preschool , Diagnosis, Differential , Fluorescein Angiography , Headache/etiology , Humans , Infant , Retrospective Studies , Vision Disorders/etiologyABSTRACT
While growth retardation and short stature are well-known features of patients with classical neurofibromatosis type 1 (NF1), we found advanced height growth and accelerated carpal bone age in patients with an NF1 microdeletion. Our analysis is based on growth data of 21 patients with common 1.4/1.2 Mb microdeletions, including three patients with a Weaver-like appearance. Overgrowth was most evident in preschool children (2-6 years, n=10, P=0.02). We conclude that childhood overgrowth is part of the phenotypic spectrum in patients with the common 1.4/1.2 Mb NF1 microdeletions and assume that the chromosomal region comprised by the microdeletions contains a gene whose haploinsufficiency causes overgrowth.
Subject(s)
Body Height/genetics , Child Development , Neurofibromatosis 1/genetics , Neurofibromin 1/genetics , Sequence Deletion , Adolescent , Adult , Child , Child, Preschool , Face/abnormalities , Female , Humans , Male , Middle Aged , Neurofibromatosis 1/etiology , Reference ValuesABSTRACT
Osteogenesis imperfecta is an inherited collagenous disease. The mildest form may present with less severe findings, for example blue sclera, but can also lead to significant handicap such as deafness or multiple bone fractures. We describe an 11-month-old female in whom bilateral chronic subdural hematoma was the leading clinical presentation of osteogenesis imperfecta type I. She was hospitalized due to epileptic seizures caused by these bilateral subdural hematomas without preceding trauma. Osteogenesis imperfecta type I was diagnosed on the basis of clinical and radiologic findings. This case demonstrates that nontraumatic chronic subdural hematoma in patients with osteogenesis imperfecta type I may be caused by impaired bone calcification, vascular fragility, and permanent friction between multiple bone fragments of the skull. Osteogenesis imperfecta type I should be considered as an underlying disease in cases of nontraumatic subdural hematoma. A thorough clinical examination is recommended to exclude subtle characteristics of the disease.