Search for a genetic cause in children with unilateral isolated microtia and congenital aural atresia.

PURPOSE: Microtia describes a spectrum of auricular malformations ranging from mild dysplasia to anotia. A vast majority of microtia patients demonstrate congenital aural atresia (CAA). Isolated microtia has a right ear predominance (58-61%) and is more common in the male sex. Isolated microtia is a multifactorial condition involving genetic and environmental causes. The aim of this study is to describe the phenotype of children with unilateral isolated microtia and CAA, and to search for a common genetic cause trough DNA analysis. METHODS: Phenotyping included a complete clinical examination. Description on the degree of auricular malformation (Weerda classification-Weerda 1988), assessment for hemifacial microsomia and age-appropriate audiometric testing were documented. Computerized tomography of the temporal bone with 3-D rendering provided a histopathological classification (HEAR classification-Declau et al. 1999). Genetic testing was carried out by single nucleotide polymorphism (SNP) microarray. RESULTS: Complete data are available for 44 children (50% was younger than 33 days at presentation; 59.1% boys; 72.7% right ear). Type III microtia was present in 28 patients. Type 2b CAA existed in 32 patients. All patients had a normal hearing at the non-affected side. Genome wide deletion duplication analysis using microarray did not reveal any pathological copy number variant (CNV) that could explain the phenotype. CONCLUSIONS: Type III microtia (peanut-shell type) in combination with a type 2b CAA was the most common phenotype, present in 23 of 44 (52.3%) patients with isolated unilateral microtia. No abnormalities could be found by copy number variant (CNV) analysis. Whole exome sequencing in a larger sample with a similar phenotype may represent a future diagnostic approach.

KRAS mutation detection and prognostic potential in sporadic colorectal cancer using high-resolution melting analysis.

BACKGROUND: The development of targeted therapies has created a pressing clinical need for molecular characterisation of cancers. In this retrospective study, high-resolution melting analysis (HRMA) was validated and implemented for screening of 164 colorectal cancer (CRC) patients to detect KRAS hot-spot mutations and to evaluate its prognostic value. Direct sequencing was used to confirm and characterise HRMA results. METHODS: After establishing its sensitivity, HRMA was validated on seven cell lines and inter- and intra-variation were analysed. The prognostic value of KRAS mutations in CRC was evaluated using survival analysis. RESULTS: HRMA revealed abnormal melting patterns in 34.1% CRC samples. Kaplan-Meier survival curves revealed a significantly shorter overall (OS) and disease-free survival (DFS) for CRC patients harbouring a KRAS mutation. In the Cox regression analysis, only when colon and rectal cancer were analysed separately, KRAS mutation was a negative predictor for OS in patients with rectal cancer and DFS in those with stage II colon cancer. CONCLUSIONS: HRMA was found to be a valid screening method for KRAS mutation detection. The KRAS mutation came forward as a negative predictive factor for OS in patients with rectal cancer and for DFS in stage II colon cancer patients.

A novel DFNB1 deletion allele supports the existence of a distant cis-regulatory region that controls GJB2 and GJB6 expression.

Eleven affected members of a large German-American family segregating recessively inherited, congenital, non-syndromic sensorineural hearing loss (SNHL) were found to be homozygous for the common 35delG mutation of GJB2, the gene encoding the gap junction protein Connexin 26. Surprisingly, four additional family members with bilateral profound SNHL carried only a single 35delG mutation. Previously, we demonstrated reduced expression of both GJB2 and GJB6 mRNA from the allele carried in trans with that bearing the 35delG mutation in these four persons. Using array comparative genome hybridization (array CGH), we have now identified on this allele a deletion of 131.4 kb whose proximal breakpoint lies more than 100 kb upstream of the transcriptional start sites of GJB2 and GJB6. This deletion, del(chr13:19,837,344-19,968,698), segregates as a completely penetrant DFNB1 allele in this family. It is not present in 528 persons with SNHL and monoallelic mutation of GJB2 or GJB6, and we have not identified any other candidate pathogenic copy number variation by arrayCGH in a subset of 10 such persons. Characterization of distant GJB2/GJB6 cis-regulatory regions evidenced by this allele may be required to find the 'missing' DFNB1 mutations that are believed to exist.

Azithromycin reduces pulmonary fibrosis in a bleomycin mouse model.

Idiopathic pulmonary fibrosis (IPF) is a devastating disease without proper treatment. Despite intensive research, the exact underlying pathogenesis remains elusive. It is regarded as a continuous injury, resulting in inflammation, infiltration, and proliferation of fibroblasts and extracellular matrix deposition, leading to an irreversible restrictive lung function deterioration and death. In this study the effect of azithromycin, a macrolide antibiotic on bleomycin-induced pulmonary fibrosis was investigated. C57BL/6 mice were intratracheally instilled with bleomycin (0.5 mg/kg) or saline. In the bleomycin group, half of the animals received azithromycin every other day from day 1 on. Bronchoalveolar lavage and histology were performed at days 7 and 35, and pulmonary function tests on day 35. At day 35, fibrotic lesions (spindle cell proliferation/collagen I deposition) were paralleled by a restrictive lung function pattern. Alterations were found in neutrophils and macrophages (innate immunity) and in T(H)2, T(H)17, and Treg cytokines (adaptive immunity). Azithromycin significantly reduced both fibrosis and the restrictive lung function pattern. This study demonstrated a beneficial effect of azithromycin on bleomycin-induced pulmonary fibrosis. A possible mechanism could be a modulation of both innate immunity and adaptive immunity. These findings might suggest a potential role for azithromycin in the treatment of IPF.

Cost-Effectiveness Analysis of Nintedanib Versus Pirfenidone in Idiopathic Pulmonary Fibrosis in Belgium.

BACKGROUND: Nintedanib (Ofev®) and pirfenidone (Esbriet®) are recommended by international guidelines as treatment options for idiopathic pulmonary fibrosis (IPF). OBJECTIVES: To compare the cost-effectiveness of nintedanib with that of pirfenidone for the treatment of IPF from a Belgian healthcare payer perspective. METHODS: The economic analysis used a Markov model that calculated outcomes over patient lifetime. Overall survival was assumed to be the same for the two comparators. Data from a network meta-analysis were used for loss of lung function, acute exacerbation events, safety and treatment discontinuation (for any reason). The health-state utility estimates in the model were calculated from EQ-5D scores collected in nintedanib studies. The assumed resource use for background care was also based on patient-level data that were categorised to fit the health states in the model and synthesised with costs and tariffs from Belgian national databases. RESULTS: Treatment with nintedanib resulted in an estimated total cost of €102,315, which was less than the total cost of treatment with pirfenidone (€113,313). Given the similarities in the survival and progression outcomes obtained with nintedanib and pirfenidone, the model predicted near equivalence in total QALYs (3.353 QALYs for the nintedanib arm and 3.318 for the pirfenidone arm). Results were largely driven by model assumptions underlying mortality, acute exacerbations and treatment discontinuation. CONCLUSIONS: After performing a synthesis of the most recently published evidence for IPF patients and assuming a Belgian healthcare payer perspective, we found nintedanib to be more cost-saving than pirfenidone.

The role of the IL23/IL17 axis in bronchiolitis obliterans syndrome after lung transplantation.

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death after lung transplantation. Treatment is challenging, as the precise pathophysiology remains unclear. We hypothesize that T(H)17 lineage plays a key role in the pathophysiology of BOS by linking T-cell activation to neutrophil influx and chronic inflammation. In a cross-sectional study, bronchoalveolar lavage (BAL) samples of 132 lung transplant recipients were analyzed. Patients were divided in four groups: stable or suffering from infection (INF), acute rejection (AR) or BOS. The upstream T(H)17 skewing (TGF-beta/IL1beta/IL6/IL23), T(H)17 counteracting (IL2), T(H)17 effector cytokine (IL17) and the principal neutrophil-attracting chemokine (IL8), were quantified at the mRNA or protein level in combination with the cell profiles. The BOS group (n = 36) showed an increase in IL1beta protein (x1.5), IL6 protein (x3), transforming growth factor-beta (TGF-beta) mRNA (x3), IL17 mRNA (x20), IL23 mRNA (x10), IL8 protein (x2), IL8 mRNA (x3) and a decrease in IL2 protein (x0.8). The infection group (n = 11) demonstrated an increase in IL1beta protein (x5), IL6 protein (x20), TGF-beta mRNA (x10), IL17 mRNA (x300), IL23 mRNA (x200) and IL8 protein (x6). The acute rejection group (n = 43) only revealed an increase in IL6 protein (x6) and IL8 protein (x2) and a decrease in IL2 protein (x0.7). Lymphocytes and neutrophils were increased in all groups compared to the stable (n = 42). Our findings demonstrate the IL23/IL17 axis to be involved in the pathophysiology of BOS potentially triggering the IL8-mediated neutrophilia. IL6, IL1beta and IL23 seem to be skewing cytokines and IL2 a counteracting cytokine for T(H)17 alignment. The involvement of TGF-beta could not be confirmed, either as T(H)17 steering or as counteracting cytokine.

Proximal chromosome 11p contiguous gene deletion syndrome phenotype: case report and review of the literature.

The proximal chromosome 11p contiguous gene deletion syndrome (P11pDS), also known as Potocki-Shaffer syndrome (PSS) or DEFECT 11 (OMIM 601224), is a disorder associated with foramina parietalia permagna and multiple osteochondroma (exostoses). Additional features include mental retardation, craniofacial anomalies, seizures and genitourinary abnormalities. Here, clinico-pathological findings of a unique patient with all of these features and, additionally, enlarged ventricles, hypertrophic obstructive cardiomyopathy and adipositas are described. The brain showed malformative lesions with hallmarks of disturbed bulk growth including micrencephaly, periventricular nodular heterotopias and focal cortical dysplasia in the nodulus of the cerebellar vermis. In addition, symmetric foci with vacuolation of the underlying neuropil, intermingled macrophages and large bizarre, partially vacuolated, reactive astrocytes were found. The proximal short arm of chromosome 11 harbors several candidate genes that could explain the patient's signs and symptoms including ALX4 and EXT2, which are always present in the interstitial deletion of the short arm of chromosome 11 in PSS. In addition, MYBPC3 would be a good candidate for the hypertrophic cardiomyopathy. Furthermore, adipositas might be related to the MAPK8IP1 gene. To the best of our knowledge, the present patient is the oldest one so far described with PSS phenotype and the only case that has undergone detailed neuropathological investigation.

The ALX4 homeobox gene is mutated in patients with ossification defects of the skull (foramina parietalia permagna, OMIM 168500).

Foramina parietalia permagna (FPP) (OMIM 168500) is caused by ossification defects in the parietal bones. Recently, it was shown that loss of function mutations in the MSX2 homeobox gene on chromosome 5 are responsible for the presence of these lesions in some FPP patients. However, the absence of MSX2 mutations in some of the FPP patients analysed and the presence of FPP associated with chromosome 11p deletions in DEFECT 11 (OMIM 601224) patients or associated with Saethre-Chotzen syndrome suggests genetic heterogeneity for this disorder. Starting from a BAC/P1/cosmid contig of the DEFECT 11 region on chromosome 11, we have now isolated the ALX4 gene, a previously unidentified member of the ALX homeobox gene family in humans. Mutation analysis of the ALX4 gene in three unrelated FPP families without the MSX2 mutation identified mutations in two families, indicating that mutations in ALX4 could be responsible for these skull defects and suggesting further genetic heterogeneity of FPP.

Identification of a 52 kb deletion downstream of the SOST gene in patients with van Buchem disease.

Van Buchem disease is an autosomal recessive skeletal dysplasia characterised by generalised bone overgrowth, predominantly in the skull and mandible. Clinical complications including facial nerve palsy, optic atrophy, and impaired hearing occur in most patients. These features are very similar to those of sclerosteosis and the two conditions are only differentiated by the hand malformations and the tall stature appearing in sclerosteosis. Using an extended Dutch inbred van Buchem family and two inbred sclerosteosis families, we mapped both disease genes to the same region on chromosome 17q12-q21, supporting the hypothesis that van Buchem disease and sclerosteosis are caused by mutations in the same gene. In a previous study, we positionally cloned a novel gene, called SOST, from the linkage interval and identified three different, homozygous mutations in the SOST gene in sclerosteosis patients leading to loss of function of the underlying protein. The present study focuses on the identification of a 52 kb deletion in all patients from the van Buchem family. The deletion, which results from a homologous recombination between Alu sequences, starts approximately 35 kb downstream of the SOST gene. Since no evidence was found for the presence of a gene within the deleted region, we hypothesise that the presence of the deletion leads to a down regulation of the transcription of the SOST gene by a cis regulatory action or a position effect.

The inner and outer of our thorax: silicone breast implants and pulmonary alveolar proteinosis.

Pulmonary alveolar (phospholipo)proteinosis (PAP) is a rare lung disease, predominantly autoimmune in nature. This case report describes a patient with insidious dyspnoea since 5 years and a milky appearance of her bronchoalveolar fluid, leading to the diagnosis of PAP. The onset of symptoms coincided with an exchange of her silicone breast implants. Giant cell reaction in axillary adenopathies pointed towards silicone leakage. Adjuvants, such as silicone, might boost pre-existing antigen reactions of the immune system, potentially leading to autoimmune phenomena.

Molecular and clinical examination of an Italian DEFECT11 family.

The DEFECT11 syndrome is a contiguous gene syndrome associated with deletions in the proximal part of chromosome 11p. In this study, we describe in an Italian family the co-existence of multiple exostoses (EXT) and enlarged parietal foramina (FPP), the two major symptoms of this syndrome, with abnormalities of the central nervous system. The latter may be a yet undescribed feature of DEFECT11 syndrome. FISH and molecular analysis allowed us to identify a small deletion on 11p11-p12, further refining the localisation of the FPP gene involved in the DEFECT11 syndrome.

Identification and characterization of a novel member of the EXT gene family, EXTL2.

Recently, two homologous genes, EXT1 and EXT2, with a putative tumor suppressor function have been described. Mutations in both genes are responsible for multiple exostosis syndrome (EXT), an autosomal dominant condition characterized by the presence of multiple osteochondromas, bony excrescences that sometimes undergo malignant transformation to chondrosarcoma. This family of EXT genes has been extended by the identification of an EXT-like (EXTL) gene showing a high degree of homology with the EXT genes. We report here a second EXT-like gene (EXTL2) which is homologous to the EXT and EXTL genes. EXTL2 consists of 5 exons encoding an ubiquitously expressed protein of 330 amino acids. In addition, a putative pseudogene, EXTL2P was also identified. The EXTL2 gene was assigned to chromosome 1p11-p12, whereas EXTL2P was mapped on chromosome 2q24-q31.

Evaluation of the role of RANK and OPG genes in Paget's disease of bone.

Paget's disease of bone (PDB) is one of the most common bone disorders in the western world. PDB is characterized by focal areas of increased osteoclastic bone resorption and bone formation, which leads to the formation of poorly structured bone. These abnormalities of bone turnover and structure predispose affected individuals to various complications including bone pain, deformity, pathological fracture, and an increased risk of osteosarcoma. One of the main mechanisms of osteoclast formation and activation involves the receptor activator of nuclear factor -kappaB (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) pathway, where binding of RANKL to RANK results in the differentiation of osteoclast precursors. OPG, on the other hand, acts as an inhibitor of osteoclastogenesis by serving as a decoy receptor for RANKL. Recently, mutations in the RANK gene have been shown to cause familial expansile osteolysis, a rare bone disorder showing great similarity to PDB. We performed mutation analysis in the RANK and OPG genes in 28 PDB patients to investigate whether mutations in these genes could be responsible for PDB. Our data suggest that RANK is not directly involved in PDB in our set of patients, as no mutations in the RANK coding region could be identified and allele frequencies of RANK polymorphisms did not differ in PDB patients as compared with the random population. Also, in the OPG gene, we could not detect PDB-causing mutations. However, of the several polymorphisms identified, one (400 + 4 C/T in intron 2), showed a statistically significant increased frequency for the C allele in PDB patients, suggesting that individuals harboring this allele may be more susceptible for developing PDB.

Molecular analysis of the putative tumour-suppressor gene EXTL1 in neuroblastoma patients and cell lines.

Although neuroblastoma is the most common extracranial solid tumour of childhood, little is known about its aetiology. Together with MYCN amplification and chromosome 17q gain, chromosome 1p deletion is one of the most frequently occurring genetic abnormalities in neuroblastoma. Based upon mapping of deletion breakpoints, putative tumour suppressor gene loci have been assigned to the distal part of the short arm of chromosome 1. Recently, the EXTL1 gene was suggested as a candidate neuroblastoma-suppressor gene and to evaluate this hypothesis, we performed 1p deletion analysis and mutation screening of the EXTL1-coding region on DNA from 22 primary neuroblastomas and 21 neuroblastoma cell lines. Deletions of the chromosome region 1p36.1, including the EXTL1 gene, were detected in several neuroblastoma cell lines and primary tumours. EXTL1 mutation screening resulted in the detection of one unclassified variant (Ser28Cys) but could not provide additional evidence of EXTL1 being involved in the aetiology of neuroblastoma.

Variability of fecal pancreatic elastase measurements in cystic fibrosis patients.

BACKGROUND: the fecal pancreatic elastase-1 (EL-1) test is a new non-invasive test for pancreatic function. The aim of the study was to evaluate the intra-patient variability of the fecal EL-1 test in a cystic fibrosis (CF) population. METHODS: 26 CF patients were recruited. Mean patient (S.D.) age was 13.7 years (5.39). Nineteen patients had classical pancreatic insufficiency (PI) based on a clinical syndrome of malabsorption plus steatorrhea on a 72 h fecal fat balance. They were all treated with enzyme supplements. Four patients had classical pancreatic sufficiency (PS): no symptoms of malabsorption, no steatorrhea on a 72 h fecal fat balance, no enzyme treatment. Two patients had symptoms suggestive of PI but had a normal 72 h fecal fat balance: (doubtful pancreatic status (PD)). The CF patients were asked to collect stool samples on 7 consecutive days. EL-1 content in the samples was measured in duplicate. A cut-off of 200 microgEL-1/g stool was used for diagnosing PI. RESULTS: mean intra-assay variability was 4.06%. All PI patients had EL-1 levels below detection limit. For the PS group maximal intra-patient variability was 35%, one stool sample EL-1 level was below the 200-microg cut-off. In the PD group the maximal intra-patient variability was 37% and EL-1 levels were inconclusive for the diagnosis of PI in both patients. CONCLUSIONS: the EL-1 test can be used for diagnosing severe PI in CF patients with overt clinical symptoms of malabsorption. However, in CF patients where the clinical picture is less clear the EL-1 test may be inconclusive due to significant intra-patient variability.