The development of the Belgian paediatric clinical trial network.

Paediatric clinical trials are critical to ensure that medications prescribed to children are safe and effective. However, evidence-based dosing and labelling of such medications remain limited, and most clinical trials in paediatrics fail. Factors for lack of trial completion include performance at site level (limited patient recruitment, limited site staff experience and lack of infrastructure), the sponsor team (limited paediatric specific expertise in design, uncertainties on robustness of biomarkers or outcome variables) as well as regulatory and administrative burdens. As a result of the growing demand for site support, the Belgian Paediatric Clinical Research Network (BPCRN) established in 2009 has been relaunched in 2018 to improve paediatric clinical trials, with the support of innovative-medicines-initiative 2 (IMI2) pan-European network conect4children (c4c) and the transatlantic network I-ACT for Children (US).This paper highlights the formation of the BPCRN and the practical insights it offers for advancing paediatric clinical trials through national networks. A national network can improve trial quality, safety and efficiency, provide clinical research expertise, identify suitable sites, and help with troubleshooting of common trial issues. The BPCRN's centralized approach has advanced paediatric clinical trials by streamlining communication and standardizing trial conduct. Challenges and opportunities have arisen, including a relaunch in 2018, orphan medicine trials, and network sustainability. Collaboration between network activities, government support, site-level improvements, efficient communication, and interaction with industry are key to achieve lasting transformation in paediatric medicine research.

Genetic variations in toll-like receptor pathway and lung function decline in Cystic fibrosis patients.

The toll-like receptor (TLR) family maintains pulmonary homeostasis by pathogen recognition, clearance and regulation of inflammation. Genes affecting inflammation response play a key role in modifying Cystic fibrosis (CF) lung disease severity. We assessed the impact of single nucleotide polymorphisms (SNPs) of TLR genes (TLR1 to TLR10, CD14, lipopolyssacharide-binding protein (LBP)) on lung function in CF patients. Each SNP was tested for time-dependent effect on FEV1, using six genetic models. In addition, we investigated associations between SNP genotypes and extreme subject specific slopes of FEV1 decline. Variant alleles of polymorphisms of TLR2 rs1898830, rs5743708, and rs3804100 demonstrated a consistent association with lung disease severity (p = 0.008, p = 0.006 and p = 0.029 respectively). Patients homozygous for variant C allele of TLR5 polymorphism rs5744174 are more frequently associated with extreme fast FEV1 decline (OR: 20 (95% Confidence Interval:1.85-216.18)). Patients homozygous AA for TLR1 polymorphism rs5743551 are more frequently associated with faster decline of FEV1 compared to heterozygous genotype (OR:7.33 (95% CI:1.63-33.11). Our findings indicate that variations in TLR1, TLR2 and TLR5 genes may influence CF lung function decline. Further functional analysis is required to provide new insights into the pathogenesis of TLRs in CF lung disease severity.

Polymorphisms in the ficolin 1 gene (FCN1) are associated with susceptibility to the development of rheumatoid arthritis.

OBJECTIVES: We investigated the possible association of rheumatoid arthritis (RA) with single nucleotide polymorphisms (SNP) within the ficolin (FCN) genes. Two SNPs in the FCN1 gene, four SNPs in the FCN2 gene and one SNP in the FCN3 gene were studied. METHODS: The SNPs within the FCN genes were detected by an experimental INNO-LiPA methodology (Innogenetics, Belgium) in a population consisting of 338 RA patients and 595 controls. The significant SNPs were further evaluated in two subpopulations and related to carriage of the human leukocyte antigen-shared epitope (HLA-SE), rheumatoid factor (RF) and the presence of anti-citrullinated protein/peptide antibodies (ACPA). RESULTS: Two SNPs in the FCN1 gene were significantly associated with RA: the A allele rs2989727 was significantly increased in RA patients (67%) compared with controls (60%) (P = 0.002). Also, the frequency of the G allele of rs1071583 was increased in RA patients (68%) compared with controls (61%) (P = 0.003). Analysis of agreement between SNPs suggested strong linkage between rs2989727 and rs1071583. Carriage of a FCN1 SNP was independent of carriage of the HLA-SE, RF status and ACPA positivity. CONCLUSIONS: We describe two linked SNPs in the FCN1 gene that are associated with the development of RA.

Extremes of L-ficolin concentration in children with recurrent infections are associated with single nucleotide polymorphisms in the FCN2 gene.

L-ficolin (also called ficolin-2, P35 or hucolin) is a soluble pattern recognition molecule of suspected importance in anti-microbial immunity. It activates the lectin pathway of complement and acts as an opsonin. l-ficolin, encoded by the FCN2 gene, recognizes microbial polysaccharides and glycoconjugates rich in GlcNAc or GalNAc. We report here data concerning four single nucleotide polymorphisms (SNPs) of the FCN2 gene and their relationship to l-ficolin serum concentrations. There are two pairs of SNPs in linkage disequilibrium: ss32469536 (located in promoter) with rs7851696 (in exon 8) and ss32469537 (promoter) with ss32469544 (exon 8). We selected groups possessing low or high serum l-ficolin concentrations (or= 4.5 microg/ml, respectively) from Polish children suffering from recurrent respiratory infections (n = 146). Low l-ficolin levels were associated with variant alleles for ss32469536 and rs7851696 and normal alleles for ss32469537 and ss32469544. Conversely, high l-ficolin levels were associated with variant alleles of ss32469537 and ss32469544. FCN2 genotyping should be a valuable additional tool for disease association studies.

Comprehensive molecular screening of the FBN1 gene favors locus homogeneity of classical Marfan syndrome.

In order to estimate the contribution of mutations at the fibrillin-1 locus (FBN1) to classical Marfan syndrome (MFS) and to study possible phenotypic differences between patients with an FBN1 mutation vs. without, a comprehensive molecular study of the FBN1 gene in a cohort of 93 MFS patients fulfilling the clinical diagnosis of MFS according to the Ghent nosology was performed. The initial mutation screening by CSGE/SSCP allowed identification of an FBN1-mutation in 73 patients. Next, sequencing of all FBN1-exons was performed in 11 mutation-negative patients, while in nine others, DHPLC was used. This allowed identification of seven and five additional mutations, respectively. Southern blot analysis revealed an abnormal hybridization pattern in one more patient. A total of 23 out of the 85 mutations identified here are reported for the first time. Phenotypic comparison of MFS patients with cysteine-involving mutations vs. premature termination mutations revealed significant differences in ocular and skeletal involvement. The phenotype of the eight patients without proven FBN1 mutation did not differ from the others with respect to the presence of major cardiac, ocular, and skeletal manifestations or positive familial history. Most likely, a portion of FBN1-mutations remains undetected because of technical limitations. In conclusion, the involvement of the FBN1-gene could be demonstrated in at least 91% of all MFS patients (85/93), which strongly suggests that this gene is the predominant, if not the sole, locus for MFS.

Acute intramural haematoma of the coeliac artery.

The report describes a previously healthy 24-year-old women presenting with acute abdominal pain following a hyperextension manoeuvre. The key finding of a continuous bruit with systolic and diastolic components in the epigastric region subsequently led to the diagnosis of an intramural haematoma of the coeliac artery, that caused a subtotal occlusion of the artery. The diagnosis was achieved by both colour-coded duplex sonography and magnetic resonance angiography. The case shows that a conservative management rather than operative reconstruction is justified in an oligo-symptomatic situation with no signs of end-organ damage as in this patient.

Homozygous Gly530Ser substitution in COL5A1 causes mild classical Ehlers-Danlos syndrome.

Skin hyperelasticity, tissue fragility with atrophic scars, and joint hypermobility are characteristic for the classical type of Ehlers-Danlos syndrome (EDS). The disease is usually inherited as an autosomal dominant trait; however, recessive mode of inheritance has been documented in tenascin-X-deficient EDS patients. Mutations in the genes coding for collagen alpha1(V) chain (COL5A1), collagen alpha2(V) chain (COL5A2), tenascin-X (TNX), and collagen alpha1(I) chain (COL1A1) have been characterized in patients with classical EDS, thus confirming the suspected genetic heterogeneity. Recently, we described a patient with severe classical EDS due to a Gly1489Glu substitution in the alpha1(V) triple-helical domain who was, in addition, heterozygous for a disease-modifying Gly530Ser substitution in the alpha1(V) NH(2)-terminal domain [Giunta and Steinmann, 2000: Am. J. Med. Genet. 90:72-79; Steinmann and Giunta, 2000: Am. J. Med. Genet. 93:342]. Here, we report on a 4-year-old boy with mild classical EDS, born to healthy consanguineous Turkish parents; the mother presented a soft skin, while the father had a normal thick skin. Ultrastructural analysis of the dermis revealed in the patient the typical "cauliflower" collagen fibrils, while in both parents variable moderate aberrations were seen. Mutation revealed the presence of a homozygous Gly530Ser substitution in the alpha1(V) collagen chains in the patient, while both parents were heterozygous for the same substitution. An additional mutation in either the COL5A1 and COL5A2 genes was excluded. Furthermore, haplotype analysis with polymorphic microsatellite markers excluded linkage to the genes coding for alpha3(V) collagen (COL5A3), tenascin-X (TNX), thrombospondin-2 (THBS2), and decorin (DCN). These new findings support further our previous hypothesis that the heterozygous Gly530Ser substitution is disease modifying and now suggest that in the homozygous state it is disease causing.

Strategies for prenatal and preimplantation genetic diagnosis in Marfan syndrome (MFS).

Marfan syndrome (MFS) is an autosomal dominant disorder with a prevalence of 2-3 per 10 000 individuals. Symptoms range from skeletal overgrowth, cutaneous striae to ectopia lentis and aortic dilatation leading to dissection. Prenatal diagnosis was until recently mainly performed in familial cases by linkage analysis. However, mutation detection has become available with thorough screening methods. The phenotypic variability observed in MFS makes reproductive options difficult, as molecular diagnosis cannot predict clinical severity of the disease. Data are presented on 15 prenatal and/or preimplantation genetic diagnoses (PGD) in nine families, originating from Belgium, the Netherlands, Spain and France. In four families data from linkage analysis were used, whereas in five other families the causative FBN1 mutation was characterised. Four PGD cycles in two couples led to one ongoing pregnancy. In addition, two amniocenteses and nine chorionic villus (CV) samplings were performed. In five pregnancies an affected fetus was diagnosed. In one of them, the couple chose to continue the pregnancy and an affected child was born, whereas the other four couples decided to terminate the pregnancy. It is expected that the greater availability of mutation testing of the FBN1 gene will increase requests for prenatal diagnosis. PGD appears to be an acceptable alternative for couples facing ethical reproductive dilemmas.

Genotype and phenotype analysis of 171 patients referred for molecular study of the fibrillin-1 gene FBN1 because of suspected Marfan syndrome.

BACKGROUND: Marfan syndrome (MFS) is an underrecognized heritable connective tissue disorder resulting from mutations in the gene for fibrillin-1 (FBN1). Affected patients are at risk for aortic dissection and/or severe ocular and orthopedic problems. The diagnosis is primarily based on a set of well-defined clinical criteria (Ghent nosology). The age-related nature of some clinical manifestations and variable phenotypic expression may hinder the diagnosis, particularly in children. Molecular analysis may be helpful to identify at-risk individuals early and start prophylactic medical treatment. FBN1 mutations have also been reported in patients with Marfan-related conditions, but it is unknown what proportion of all FBN1 mutation carriers they represent. METHODS: We reviewed the clinical and molecular data of 171 consecutive patients referred for FBN1 analysis because either MFS was diagnosed or they had signs suggestive of MFS. We compared the incidence of mutations in patients who fulfilled the clinical diagnostic criteria for MFS with those who did not. RESULTS: Diagnostic criteria for MFS were fulfilled in 94 patients, 62 (66%) of whom had an FBN1 mutation. A significantly higher incidence of ectopia lentis was found in the patients with MFS with an FBN1 mutation vs those without (P=.04). Among the 77 patients who did not meet the criteria, an FBN1 mutation was found in 9 patients (12%). No correlation was found between the severity of the phenotype and the position and nature of the FBN1 mutation. CONCLUSIONS: This study showed a significant difference in the number of FBN1 mutations between patients fulfilling and those not fulfilling the diagnostic criteria for MFS, which seems to be a good predictor of the presence of an FBN1 mutation. A comprehensive clinical evaluation is mandatory before establishing a definitive diagnosis. An FBN1 mutation analysis is helpful to identify individuals at high risk for MFS who need careful follow-up, particularly in families displaying phenotypic variability and in children.

Short stature, abnormal face, joint laxity, dislocation, hernias, delayed bone age, and severe psychomotor retardation in two brothers: previously undescribed MCA/MR syndrome.

We describe two brothers with severe psychomotor retardation, short stature, microbrachycephaly, flat occiput, ptosis, low set and prominent ears, "beaked" nose, joint hyperlaxity and dislocation, hernias, delayed bone age, and abnormalities on skin biopsy. Their parents are first cousins. To the best of our knowledge, this syndrome has not been reported before.

Characterization of mutations leading to recessive dystrophic epidermolysis bullosa and Marfan syndrome in a single patient.

Dystrophic epidermolysis bullosa (DEB) is a rare genetic skin disorder. In this report we have investigated an Italian child affected with recessive DEB (RDEB) and demonstrated that he was homozygous for the mutation R226X in the type VII collagen gene (COL7A1), leading to absence of type VII collagen at the dermal-epidermal junction. There was no family history of inherited skin blistering but the child's father was affected by Marfan syndrome, an autosomal dominant connective tissue disorder that results from mutations in the fibrillin-1 gene (FBN1). Analysis of this gene showed that the RDEB patient and his father were both heterozygous for a novel FBN1 mutation, C1971Y. This mutation affects one of the six obligate cysteine residues within one of the calcium-binding epidermal growth factor-like regions of the protein. At the age of 2-years the RDEB patient showed signs of early aortic dilatation, suggesting that he is likely to develop a Marfan syndrome phenotype in the future. This is a unique case of these two coexisting inherited disorders.

Association of the type I collagen alpha1 Sp1 polymorphism, bone density and upper limb muscle strength in community-dwelling elderly men.

A polymorphic binding site of the Sp1 transcription factor in the gene encoding the alpha1 chain of type I collagen is associated with bone mineral density (BMD) and, independently, with fracture risk in postmenopausal women. The aim of this study is to examine whether in community-dwelling men over age 70 years, the COL1A1 Sp1 polymorphism is associated with BMD (by dual-energy X-ray absorptiometry) and/or with bone turnover and muscle strength--factors related to both BMD and fracture risk. The COL1A1 Sp1 genotype (SS, Ss and ss) was determined using polymerase chain reaction and MscI restriction digestion. Presence of the s allele was significantly associated with lower BMD at the distal forearm (p = 0.03) and different distal radius subregions, with Z-score differences between extreme genotype groups (SS vs ss) ranging from 0.87 (ultradistal radius; p = 0.17) to 1.31 (mid-region of distal radius; p = 0.03). Presence of the s allele was also associated with lower BMD at the hip, with differences between genotypes not approaching statistical significance. There were no differences between genotype groups for any of the assessed markers of bone formation and resorption. Presence of the s allele was associated with lower grip (p = 0.03) and biceps strength (p = 0.04) at the dominant arm, with the difference between extreme genotype groups amounting to 21% and 30%, respectively. In a multivariate analysis, the association between COL1A1 Sp1 polymorphism and forearm BMD Z-score was no longer significant after adjustment for height, percentage lean mass, level of physical activity and upper limb strength (p = 0.18), whereas the genotype-specific difference for grip and biceps strength remained significant after adjustment for age, height and percentage lean mass (p = 0.04 and p= 0.05, respectively). In conclusion, the COL1A1 Sp1 polymorphism is associated with BMD at the forearm and upper limb muscle strength in elderly men, the findings of multivariate analyses suggesting that the genotype-specific differences for BMD might be mediated, at least in part, by differences in muscle strength.

A novel disorder caused by defective biosynthesis of N-linked oligosaccharides due to glucosidase I deficiency.

Glucosidase I is an important enzyme in N-linked glycoprotein processing, removing specifically distal alpha-1,2-linked glucose from the Glc3Man9GlcNAc2 precursor after its en bloc transfer from dolichyl diphosphate to a nascent polypeptide chain in the endoplasmic reticulum. We have identified a glucosidase I defect in a neonate with severe generalized hypotonia and dysmorphic features. The clinical course was progressive and was characterized by the occurrence of hepatomegaly, hypoventilation, feeding problems, seizures, and fatal outcome at age 74 d. The accumulation of the tetrasaccharide Glc(alpha1-2)Glc(alpha1-3)Glc(alpha1-3)Man in the patient's urine indicated a glycosylation disorder. Enzymological studies on liver tissue and cultured skin fibroblasts revealed a severe glucosidase I deficiency. The residual activity was <3% of that of controls. Glucosidase I activities in cultured skin fibroblasts from both parents were found to be 50% of those of controls. Tissues from the patient subjected to SDS-PAGE followed by immunoblotting revealed strongly decreased amounts of glucosidase I protein in the homogenate of the liver, and a less-severe decrease in cultured skin fibroblasts. Molecular studies showed that the patient was a compound heterozygote for two missense mutations in the glucosidase I gene: (1) one allele harbored a G-->C transition at nucleotide (nt) 1587, resulting in the substitution of Arg at position 486 by Thr (R486T), and (2) on the other allele a T-->C transition at nt 2085 resulted in the substitution of Phe at position 652 by Leu (F652L). The mother was heterozygous for the G-->C transition, whereas the father was heterozygous for the T-->C transition. These base changes were not seen in 100 control DNA samples. A causal relationship between the alpha-glucosidase I deficiency and the disease is postulated.

Glycine to tryptophan substitution in type I collagen in a patient with OI type III: a unique collagen mutation.

We report a unique glycine substitution in type I collagen and highlight the clinical and biochemical consequences. The proband is a 9 year old Turkish boy with severely deforming osteogenesis imperfecta (OI). Biochemical analysis of (pro) collagen type I from a skin fibroblast culture showed both normal and overmodified alpha chains. Molecular analysis showed a G>T transversion in the COL1A2 gene, resulting in the substitution of glycine by tryptophan at position 277 of the alpha2(I) collagen chain. Glycine substitutions in type I collagen are the most frequent cause of the severe and lethal forms of OI. The phenotypic severity varies according to the nature and localisation of the mutation. Substitutions of glycine by tryptophan, which is the most voluminous amino acid, have not yet been identified in type I collagen or any other fibrillar collagen. The severe, though non-lethal OI phenotype associated with this mutation may appear surprising in view of the huge size of the tryptophan residue. The fact that the mutation resides within a so called "non-lethal" region of the alpha2(I) collagen chain supports a regional model in phenotypic severity for alpha2(I) collagen mutations, in which the phenotype is determined primarily by the nature of the collagen domain rather than the type of glycine substitution involved.

Report of five novel and one recurrent COL2A1 mutations with analysis of genotype-phenotype correlation in patients with a lethal type II collagen disorder.

Achondrogenesis II-hypochondrogenesis and severe spondyloepiphyseal dysplasia congenita (SEDC) are lethal forms of dwarfism caused by dominant mutations in the type II collagen gene (COL2A1). To identify the underlying defect in seven cases with this group of conditions, we used the combined strategy of cartilage protein analysis and COL2A1 mutation analysis. Overmodified type II collagen and the presence of type I collagen was found in the cartilage matrix of all seven cases. Five patients were heterozygous for a nucleotide change that predicted a glycine substitution in the triple helical domain (G313S, G517V, G571A, G910C, G943S). In all five cases, analysis of cartilage type II collagen suggested incorporation of the abnormal alpha1(II) chain in the extracellular collagen trimers. The G943S mutation has been reported previously in another unrelated patient with a strikingly similar phenotype, illustrating the possible specific effect of the mutation. The radiographically less severely affected patient was heterozygous for a 4 bp deletion in the splice donor site of intron 35, likely to result in aberrant splicing. One case was shown to be heterozygous for a single nucleotide change predicted to result in a T1191N substitution in the carboxy-propeptide of the proalpha1(II) collagen chain. Study of the clinical, radiographic, and morphological features of the seven cases supports evidence for a phenotypic continuum between achondrogenesis II-hypochondrogenesis and lethal SEDC and suggests a relationship between the amount of type I collagen in the cartilage and the severity of the phenotype.

Classical Ehlers-Danlos syndrome caused by a mutation in type I collagen.

Classical Ehlers-Danlos syndrome (EDS) is characterized by skin hyperelasticity, joint hypermobility, increased tendency to bruise, and abnormal scarring. Mutations in type V collagen, a regulator of type I collagen fibrillogenesis, have been shown to underlie this type of EDS. However, to date, mutations have been found in only a limited number of patients, which suggests genetic heterogeneity. In this article, we report two unrelated patients with typical features of classical EDS, including excessive skin fragility, in whom we found an identical arginine-->cysteine substitution in type I collagen, localized at position 134 of the alpha1(I) collagen chain. The arginine residue is highly conserved and localized in the X position of the Gly-X-Y triplet. As a consequence, intermolecular disulfide bridges are formed, resulting in type I collagen aggregates, which are retained in the cells. Whereas substitutions of glycine residues in type I collagen invariably result in osteogenesis imperfecta, substitutions of nonglycine residues in type I collagen have not yet been associated with a human disease. In contrast, arginine-->cysteine substitutions in type II collagen have been identified in a variety of chondrodysplasias. Our findings show that mutations in other fibrillar collagens can be causally involved in classical EDS and point to genetic heterogeneity of this disorder.