Characteristics of Café-au-lait Macules and their Association with the Neurofibromatosis type I Genotype in a Cohort of Greek Children.

Cafe-au-lait macules are the most distinctive clinical finding in neurofibromatosis type I. The aim of this prospective study of Greek children diagnosed with neurofibromatosis type I was to describe the dermatological phenotype and to analyse the characteristics of cafe-au-lait macules and their association with genotype. Pigment intensity and melatonin content of cafe-au-lait macules were measured with a narrowband spectrophotometer. A total of 63 children aged 6 months to 16 years old were studied. Mean melanin content varied, both among patients, and within each patient (p < 0.001). Females had a higher number of cafe-au-lait macules than did males (p = 0.025), and the melanin content of cafe-au-lait macules was lower in females than males (p < 0.001). Patients with protein-truncating variants in the neurofibromatosis type I gene had higher melanin content of cafe-au-lait macules than other types of genetic variants t (55) = 2.196, p = 0.032. Plexiform neurofibromas were also detected in the majority of patients with protein- truncating variants, while juvenile xanthogranulomas were detected equally in patients with protein-truncating and non-protein-truncating variants. In conclusion, cafe-au-lait macules with high melatonin content are associated with patients carrying non-protein-truncating variants. Therefore, measurement of cafe-au-lait macule pigment intensity might provide useful information for initial assessment of patients with neurofibromatosis type I and the severity of their future phenotype.

239-kb Microdeletion Spanning KMT2E in a Child with Developmental Delay: Further Delineation of the Phenotype.

Pathogenic KMT2E variants underly O'Donnell-Luria-Rodan syndrome, a recently described neurodevelopmental disorder characterized by global developmental delay, variable degrees of intellectual disability, and subtle facial dysmorphism. Less common findings include autism, seizures, gastrointestinal (GI) problems, and abnormal head circumference. Occurrence of mostly truncating variants as well as the similar phenotype observed in individuals with deletions spanning KMT2E suggest haploinsufficiency of this gene as a common mechanism for the disorder, while a gain-of-function or dominant-negative effect cannot be ruled out for some missense variants. Deletions reported in the literature encompass several additional known or presumed haploinsufficient genes, thus leading to more complex phenotypes. Here, we describe a male with antenatal onset hydronephrosis, hypotonia, global developmental delay, prominent GI symptoms as well as facial dysmorphism. Chromosomal microarray revealed a 239-kb de novo microdeletion spanning KMT2E and LHFPL3. Clinical presentation of our proband, harboring one of the smallest deletions of the region confirms the core features of this disorder, suggests GI symptoms as a prominent finding in affected individuals while expanding the phenotypic spectrum to abnormalities of the urinary tract.

Development of a multidisciplinary clinic of neurofibromatosis type 1 and other neurocutaneous disorders in Greece. A 3-year experience.

Given the complexity of neurocutaneous syndromes, a multidisciplinary approach has been advocated in order to provide optimum care. Subjects and Methods: Retrospective analysis of a cohort of 157 patients during a 3-year period, seen at a newly developed neurocutaneous clinic in a pediatric tertiary care hospital in Athens (Greece); and systematic chart review of the patients diagnosed with neurofibromatosis type 1 during this time period. Results: The most frequent neurocutaneous syndromes were neurofibromatosis type 1 (NF1) in 89 patients and tuberous sclerosis complex in 17. In 20.38% of patients a neurocutaneous syndrome was not confirmed. Approximately 2/3 of the NF1 patients underwent genetic analysis, and for 76.67% of them, a pathogenic mutation on the NF1 gene was revealed. Eighty-one patients manifested with generalized NF1 and eight with mosaic NF1. Dermatological manifestations included café-au-lait macules in all patients, followed by axillary and/or inguinal freckling (n = 57), external plexiform neurofibromas (n = 17), and cutaneous and subcutaneous neurofibromas (n = 11). Approximately half of patients had learning disabilities and attention deficit hyperactivity disorder, followed by mental retardation (n = 9), autistic spectrum disorders (n = 4), headaches (n = 3) and seizures (n = 2). Neuroimaging showed characteristic areas of hyperintensity on T2-weighted images in 74.07% of patients and optic pathway glioma in 19.75%. Two patients developed malignant peripheral sheath nerve tumor. Conclusions: Neurocutaneous syndromes are clinically heterogeneous and the surveillance of potential clinical complications is challenging. The availability of genetic diagnosis and novel imaging methods in this group of disorders is likely to further expand their clinical spectrum. Guidelines for assessment and management will need to be modified based on new available data.

Phenotypic expression of a spectrum of Neurofibromatosis Type 1 (NF1) mutations identified through NGS and MLPA.

Neurofibromatosis Type 1 (NF1) is caused by mutations of the NF1 gene. The aim of this study was to identify the genetic causes underlying the disease, attempt possible phenotype/genotype correlations and add to the NF1 mutation spectrum. A screening protocol based on genomic DNA was established in 168 patients, encompassing sequencing of all coding exons and adjoining introns using a custom targeted next generation sequencing protocol and subsequent confirmation of findings with Sanger sequencing. MLPA was used to detect deletions/duplications and positive findings were confirmed by RNA analysis. All novel findings were evaluated according to ACMG Standards and guidelines for the interpretation of sequence variants with the aid of in-silico bioinformatic tools and family segregation analysis. A germline variant was identified in 145 patients (86%). In total 49 known and 70 novel variants in coding and non-coding regions were identified. Seven patients carried whole or partial gene deletions. NF1 patients, present with high phenotypic variability even in cases where the same germline disease causing variant has been identified. Our findings will contribute to a better knowledge of the genetic causes and the phenotypic expression related to the disease.

Genomic screening of ABCA4 and array CGH analysis underline the genetic variability of Greek patients with inherited retinal diseases.

BACKGROUND: Retinal dystrophies are a clinically and genetically heterogeneous group of disorders which affect more than two million people worldwide. The present study focused on the role of the ABCA4 gene in the pathogenesis of hereditary retinal dystrophies (autosomal recessive Stargardt disease, autosomal recessive cone-rod dystrophy, and autosomal recessive retinitis pigmentosa) in patients of Greek origin. MATERIALS AND METHODS: Our cohort included 26 unrelated patients and their first degree healthy relatives. The ABCA4 mutation screening involved Sanger sequencing of all exons and flanking regions. Evaluation of novel variants included sequencing of control samples, family segregation analysis and characterization by in silico prediction tools. Twenty five patients were also screened for copy number variations by array-comparative genomic hybridization. RESULTS: Excluding known disease-causing mutations and polymorphisms, two novel variants were identified in coding and non-coding regions of ABCA4. Array-CGH analysis revealed two partial deletions of USH2A and MYO3A in two patients with nonsyndromic autosomal recessive retinitis pigmentosa. CONCLUSIONS: The ABCA4 mutation spectrum in Greek patients differs from other populations. Bioinformatic tools, segregation analysis along with clinical data from the patients seemed to be crucial for the evaluation of genetic variants and particularly for the discrimination between causative and non-causative variants.

BTNL2 gene SNPs as a contributing factor to sarcoidosis pathogenesis in a cohort of Greek patients.

Sarcoidosis is a multisystemic granulomatous disease of unknown etiology that primarily affects adults between the ages of 20 and 40 years old. It is characterized by the activation of Th1 lymphocytes resulting in the production of inflammatory cytokines and the formation of noncaseating epithelioid cell granulomas in affected tissues. The lungs and lymphatic system are the ones most frequently affected. The disease usually presents spontaneous remission in the first two years and, in a few patients, the disease progresses to pulmonary fibrosis or other fatal complications depending on the affected organ. The pathogenesis of sarcoidosis is still not clearly defined, and is considered an interaction between the environment and risk alleles in many genes. The present case control study consisted of 146 Greek patients with sarcoidosis and 90 healthy volunteers from the same ethnic group. The coding and neighboring intronic regions of the BTNL2 gene were sequenced and risk alleles were compared amongst the two groups. Thirty-seven different variants were detected from which 12 were synonymous substitutions and 25 non-synonymous. With the help of in silico tools (SIFT, PolyPhen, PROVEAN, PMut and EX_SKIP), 13 variants were classified as possible pathological risk variants including 4 novel ones. The most common risk variants contributing to phenotypic modulation of sarcoidosis were p.S360G and p.S334L, with the latter contributing to a more severe disease stage with extra-pulmonary manifestations such as skin granulomas and relapses being more common.

Cystic fibrosis conductance regulator, tumor necrosis factor, interferon alpha-10, interferon alpha-17, and interferon gamma genotyping as potential risk markers in pulmonary sarcoidosis pathogenesis in Greek patients.

Sarcoidosis is a complex disease with autoimmune basis and still unknown etiology. We have screened for mutations in the cystic fibrosis conductance regulator (CFTR) gene and genotyped single-nucleotide polymorphisms in the tumor necrosis factor (TNF), interferon alpha-10 (IFNA10), IFNA17, and interferon gamma (IFNG) genes in 89 Greek patients with sarcoidosis and 212 control subjects to detect possible association between them and the risk for developing sarcoidosis. We have found a statistically significant increase (p = 6.1 x 10(-8)) of CFTR mutation carriers in the population of patients with sarcoidosis versus the control population. A difference was also noted within the group of patients with sarcoidosis where the ones with CFTR mutations suffered more frequently from dyspnea than those without (p = 5 x 10(-6)). Our study did not reproduce the associations previously noted with the TNF, IFNA10, IFNA17, and IFNG genes, which highlights the genetic complexity of the disorder and is in agreement with previous studies showing that CFTR might be an important factor in the clinical course of the disease.

Association of TLR4 single-nucleotide polymorphisms and sarcoidosis in Greek patients.

The present study investigates the potential role of Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile single-nucleotide polymorphisms (SNPs) as risk factors in the development of sarcoidosis using a novel high-throughput microtiter well-based bioluminometric genotyping assay. One hundred and nineteen Greek patients with sarcoidosis and 209 control subjects were genotyped for the two SNPs of the TLR4 gene. The genotypes observed were in Hardy-Weinberg equilibrium. The heterozygote frequency for both SNPs in sarcoidosis group and control population was 13.4% (16/119) and 10.5% (22/209), respectively. The minor genotype was found to be the same for both sarcoidosis and control groups and similar to that found in other Caucasian populations. No significant association of Asp299Gly and Thr399Ile polymorphisms with increased susceptibility to sarcoidosis was found (p = 0.61 and odds ratio = 1.183). In conclusion, genotype data for the TLR4 Asp299Gly and Thr399Ile polymorphisms in the Greek population were found to be in linkage disequilibrium, and no contribution in the pathogenesis of sarcoidosis was established. Further, in course of the present study, we demonstrated a very simple and sensitive high-throughput bioluminometric assay for genotyping Asp299Gly and Thr399Ile polymorphisms in the TLR4 gene.