Intestinal stroma guides monocyte differentiation to macrophages through GM-CSF

Stromal cells support epithelial cell and immune cell homeostasis and play an important role in inflammatory bowel disease (IBD) pathogenesis. Here, we quantify the stromal response to inflammation in pediatric IBD and reveal subset-specific inflammatory responses across colon segments and intestinal layers. Using data from a murine dynamic gut injury model and human ex vivo transcriptomic, protein and spatial analyses, we report that PDGFRA+CD142-/low fibroblasts and monocytes/macrophages co-localize in the intestine. In primary human fibroblast-monocyte co-cultures, intestinal PDGFRA+CD142-/low fibroblasts foster monocyte transition to CCR2+CD206+ macrophages through granulocyte-macrophage colony-stimulating factor (GM-CSF). Monocyte-derived CCR2+CD206+ cells from co-cultures have a phenotype similar to intestinal CCR2+CD206+ macrophages from newly diagnosed pediatric IBD patients, with high levels of PD-L1 and low levels of GM-CSF receptor. The study describes subset-specific changes in stromal responses to inflammation and suggests that the intestinal stroma guides intestinal macrophage differentiation.

Event-free survival of maralixibat-treated patients with Alagille syndrome compared to a real-world cohort from GALA

BACKGROUND AND AIMS

Alagille syndrome (ALGS) is characterized by chronic cholestasis with associated pruritus and extrahepatic anomalies. Maralixibat, an ileal bile acid transporter inhibitor, is an approved pharmacologic therapy for cholestatic pruritus in ALGS. Since long-term placebo-controlled studies are not feasible or ethical in children with rare diseases, a novel approach was taken comparing 6-year outcomes from maralixibat trials with an aligned and harmonized natural history cohort from the G lobal AL agille A lliance (GALA) study.

APPROACH AND RESULTS

Maralixibat trials comprise 84 patients with ALGS with up to 6 years of treatment. GALA contains retrospective data from 1438 participants. GALA was filtered to align with key maralixibat eligibility criteria, yielding 469 participants. Serum bile acids could not be included in the GALA filtering criteria as these are not routinely performed in clinical practice. Index time was determined through maximum likelihood estimation in an effort to align the disease severity between the two cohorts with the initiation of maralixibat. Event-free survival, defined as the time to first event of manifestations of portal hypertension (variceal bleeding, ascites requiring therapy), surgical biliary diversion, liver transplant, or death, was analyzed by Cox proportional hazards methods. Sensitivity analyses and adjustments for covariates were applied. Age, total bilirubin, gamma-glutamyl transferase, and alanine aminotransferase were balanced between groups with no statistical differences. Event-free survival in the maralixibat cohort was significantly better than the GALA cohort (HR, 0.305; 95% CI, 0.189-0.491; p <0.0001). Multiple sensitivity and subgroup analyses (including serum bile acid availability) showed similar findings.

CONCLUSIONS

This study demonstrates a novel application of a robust statistical method to evaluate outcomes in long-term intervention studies where placebo comparisons are not feasible, providing wide application for rare diseases. This comparison with real-world natural history data suggests that maralixibat improves event-free survival in patients with ALGS.

Myeloid cells from Langerhans cell histiocytosis patients exhibit increased vesicle trafficking and an altered secretome capable of activating NK cells

Langerhans cell histiocytosis (LCH) is a potentially life-threatening inflammatory myeloid neoplasia linked to pediatric neurodegeneration, whereby transformed LCH cells form agglomerated lesions in various organs. Although MAP-kinase pathway mutations have been identified in LCH cells, the functional consequences of these mutations and the mechanisms that cause the pathogenic behavior of LCH cells are not well understood. In our study, we used an in vitro differentiation system and RNA-sequencing to compare monocyte-derived dendritic cells from LCH patients to those derived from healthy controls or patients with Crohn's disease, a non-histiocytic inflammatory disease. We observed that interferon-γ treatment exacerbated intrinsic differences between LCH patient and control cells, including strikingly increased endo- and exocytosis gene activity in LCH patients. We validated these transcriptional patterns in lesions and functionally confirmed that LCH cells exhibited increased endo- and exocytosis. Furthermore, RNA-sequencing of extracellular vesicles revealed the enrichment of pathological transcripts involved in cell adhesion, MAP-kinase pathway, vesicle trafficking and T-cell activation in LCH patients. Thus, we tested the effect of the LCH secretome on lymphocyte activity and found significant activation of NK cells. These findings implicate extracellular vesicles in the pathology of LCH for the first time, in line with their established roles in the formation of various other tumor niches. Thus, we describe novel traits of LCH patient cells and suggest a pathogenic mechanism of potential therapeutic and diagnostic importance.

Development of a core outcome set for pediatric chronic intestinal failure

BACKGROUND

In research on pediatric chronic intestinal failure, heterogeneity in reported definitions and outcomes exists. This leads to a risk of reporting bias and impossibility of evidence synthesis. Also, reported outcomes should be relevant to both healthcare providers and patients and their parents. Therefore, the aim of this study is to create a core outcome set (COS) to be used in studies on pediatric chronic intestinal failure.

METHODS

Candidate outcomes were selected from a recent systematic review. A three-round Delphi study among key stakeholders and a consensus meeting with an expert panel were undertaken to achieve consensus on the COS.

RESULTS

Seventy-two stakeholders (79%) completed all three rounds of the Delphi process. Ninety-eight outcomes were assessed, and five new outcomes were added after the first round. Ten outcomes were included in the final COS: weaning from parenteral nutrition, growth, mortality, central line-related infection, central line longevity, sepsis not related to central line infection, central line-related thrombosis, intestinal failure-associated liver disease, (serious) adverse events, and health-related quality of life.

CONCLUSION

This pediatric chronic intestinal failure COS consists of 10 outcomes important for all key stakeholders. Usage of this set in future research should minimize outcome heterogeneity and enhance the value of evidence synthesis. This will lead to better management in this field of rare gastrointestinal conditions.

Natural history of liver disease in a large international cohort of children with Alagille syndrome: Results from the GALA study

BACKGROUND AND AIMS

Alagille syndrome (ALGS) is a multisystem disorder, characterized by cholestasis. Existing outcome data are largely derived from tertiary centers, and real-world data are lacking. This study aimed to elucidate the natural history of liver disease in a contemporary, international cohort of children with ALGS.

APPROACH AND RESULTS

This was a multicenter retrospective study of children with a clinically and/or genetically confirmed ALGS diagnosis, born between January 1997 and August 2019. Native liver survival (NLS) and event-free survival rates were assessed. Cox models were constructed to identify early biochemical predictors of clinically evident portal hypertension (CEPH) and NLS. In total, 1433 children (57% male) from 67 centers in 29 countries were included. The 10 and 18-year NLS rates were 54.4% and 40.3%. By 10 and 18 years, 51.5% and 66.0% of children with ALGS experienced ≥1 adverse liver-related event (CEPH, transplant, or death). Children (>6 and ≤12 months) with median total bilirubin (TB) levels between ≥5.0 and <10.0 mg/dl had a 4.1-fold (95% confidence interval [CI], 1.6-10.8), and those ≥10.0 mg/dl had an 8.0-fold (95% CI, 3.4-18.4) increased risk of developing CEPH compared with those <5.0 mg/dl. Median TB levels between ≥5.0 and <10.0 mg/dl and >10.0 mg/dl were associated with a 4.8 (95% CI, 2.4-9.7) and 15.6 (95% CI, 8.7-28.2) increased risk of transplantation relative to <5.0 mg/dl. Median TB <5.0 mg/dl were associated with higher NLS rates relative to ≥5.0 mg/dl, with 79% reaching adulthood with native liver ( p < 0.001).

CONCLUSIONS

In this large international cohort of ALGS, only 40.3% of children reach adulthood with their native liver. A TB <5.0 mg/dl between 6 and 12 months of age is associated with better hepatic outcomes. These thresholds provide clinicians with an objective tool to assist with clinical decision-making and in the evaluation of therapies.

Notch-dependent cooperativity between myeloid lineages promotes Langerhans cell histiocytosis pathology

Langerhans cell histiocytosis (LCH) is a potentially fatal neoplasm characterized by the aberrant differentiation of mononuclear phagocytes, driven by mitogen-activated protein kinase (MAPK) pathway activation. LCH cells may trigger destructive pathology yet remain in a precarious state finely balanced between apoptosis and survival, supported by a unique inflammatory milieu. The interactions that maintain this state are not well known and may offer targets for intervention. Here, we used single-cell RNA-seq and protein analysis to dissect LCH lesions, assessing LCH cell heterogeneity and comparing LCH cells with normal mononuclear phagocytes within lesions. We found LCH discriminatory signatures pointing to senescence and escape from tumor immune surveillance. We also uncovered two major lineages of LCH with DC2- and DC3/monocyte-like phenotypes and validated them in multiple pathological tissue sites by high-content imaging. Receptor-ligand analyses and lineage tracing in vitro revealed Notch-dependent cooperativity between DC2 and DC3/monocyte lineages during expression of the pathognomonic LCH program. Our results present a convergent dual origin model of LCH with MAPK pathway activation occurring before fate commitment to DC2 and DC3/monocyte lineages and Notch-dependent cooperativity between lineages driving the development of LCH cells.

Genotype-phenotype relationships of truncating mutations, p.E297G and p.D482G in bile salt export pump deficiency

Background & Aims

Bile salt export pump (BSEP) deficiency frequently necessitates liver transplantation in childhood. In contrast to two predicted protein truncating mutations (PPTMs), homozygous p.D482G or p.E297G mutations are associated with relatively mild phenotypes, responsive to surgical interruption of the enterohepatic circulation (siEHC). The phenotype of patients with a compound heterozygous genotype of one p.D482G or p.E297G mutation and one PPTM has remained unclear. We aimed to assess their genotype-phenotype relationship.

Methods

From the NAPPED database, we selected patients with homozygous p.D482G or p.E297G mutations (BSEP1/1; n = 31), with one p.D482G or p.E297G, and one PPTM (BSEP1/3; n = 30), and with two PPTMs (BSEP3/3; n = 77). We compared clinical presentation, native liver survival (NLS), and the effect of siEHC on NLS.

Results

The groups had a similar median age at presentation (0.7-1.3 years). Overall NLS at age 10 years was 21% in BSEP1/3 vs. 75% in BSEP1/1 and 23% in BSEP3/3 (p <0.001). Without siEHC, NLS in the BSEP1/3 group was similar to that in BSEP3/3, but considerably lower than in BSEP1/1 (at age 10 years: 38%, 30%, and 71%, respectively; p = 0.003). After siEHC, BSEP1/3 and BSEP3/3 were associated with similarly low NLS, while NLS was much higher in BSEP1/1 (10 years after siEHC, 27%, 14%, and 92%, respectively; p <0.001).

Conclusions

Individuals with BSEP deficiency with one p.E297G or p.D482G mutation and one PPTM have a similarly severe disease course and low responsiveness to siEHC as those with two PPTMs. This identifies a considerable subgroup of patients who are unlikely to benefit from interruption of the enterohepatic circulation by either surgical or ileal bile acid transporter inhibitor treatment.

Impact and implications

This manuscript defines the clinical features and prognosis of individuals with BSEP deficiency involving the combination of one relatively mild and one very severe BSEP deficiency mutation. Until now, it had always been assumed that the mild mutation would be enough to ensure a relatively good prognosis. However, our manuscript shows that the prognosis of these patients is just as poor as that of patients with two severe mutations. They do not respond to biliary diversion surgery and will likely not respond to the new IBAT (ileal bile acid transporter) inhibitors, which have recently been approved for use in BSEP deficiency.

Intestinal gluconeogenesis is downregulated in pediatric patients with celiac disease

BACKGROUND

Untreated celiac disease (CD) patients have increased levels of blood glutamine and a lower duodenal expression of glutaminase (GLS). Intestinal gluconeogenesis (IGN) is a process through which glutamine is turned into glucose in the small intestine, for which GLS is crucial. Animal studies suggest impaired IGN may have long-term effects on metabolic control and be associated with the development of type 2 diabetes and non-alcoholic fatty liver disease (NAFLD). The aim of this study was to thoroughly investigate IGN at the gene expression level in children with untreated celiac disease.

METHODS

Quantitative polymerase chain reaction (qPCR) was used to quantify the expression of 11 target genes related to IGN using the delta-delta Ct method with three reference genes (GUSB, IPO8, and YWHAZ) in duodenal biopsies collected from 84 children with untreated celiac disease and 58 disease controls.

RESULTS

Significantly lower expression of nine target genes involved in IGN was seen in duodenal biopsies from CD patients compared with controls: FBP1, G6PC, GLS, GPT1, PCK1, PPARGC1A, SLC2A2, SLC5A1, and SLC6A19. No significant difference in the expression was observed for G6PC3 or GOT1.

CONCLUSIONS

Children with untreated celiac disease have lower expression of genes important for IGN. Further studies are warranted to disentangle whether this is a consequence of intestinal inflammation or due to an impaired metabolic pathway shared with other chronic metabolic diseases. Impaired IGN could be a mechanism behind the increased risk of NAFLD seen in CD patients.

Non-alcoholic fatty liver disease in children and young adults is associated with increased long-term mortality

BACKGROUND & AIMS

Longitudinal data are scarce regarding the natural history and long-term risk of mortality in children and young adults with biopsy-confirmed non-alcoholic fatty liver disease (NAFLD).

METHODS

This nationwide, matched cohort study included all Swedish children and young adults (≤25 years) with biopsy-confirmed NAFLD (1966-2017; n = 718). NAFLD was confirmed histologically from all liver biopsies submitted to Sweden's 28 pathology departments, and further categorized as simple steatosis or steatohepatitis (NASH). Patients with NAFLD were matched to ≤5 general population controls by age, sex, calendar year and county (n = 3,457). To account for shared genetic and early-life factors, we also matched patients with NAFLD to full-sibling comparators. Using Cox regression, we estimated multivariable-adjusted hazard ratios (aHRs) and 95% CIs.

RESULTS

Over a median of 15.8 years, 59 patients with NAFLD died (5.5/1,000 person-years [PY]) compared to 36 population controls (0.7/1,000 PY; difference = 4.8/1,000 PY; multivariable aHR 5.88; 95% CI 3.77-9.17), corresponding to 1 additional death per 15 patients with NAFLD, followed for 20 years. The 20-year absolute risk of overall mortality was 7.7% among patients with NAFLD, and 1.1% among controls (difference = 6.6%; 95% CI 4.0-9.2). Findings persisted after excluding those who died within the first 6 months (aHR 4.65; 95% CI 2.92-7.42), and after using full-sibling comparators (aHR 11.72; 95% CI 3.18-43.23). Simple steatosis was associated with a 5.26-fold higher adjusted rate of mortality compared to controls (95% CI 3.05-9.07), and this was amplified with NASH (aHR 11.51, 95% CI 4.77-27.79). Most of the excess mortality was from cancer (1.67 vs. 0.07/1,000PY; aHR 15.60; 95% CI 4.97-48.93), liver disease (0.93 vs. 0.04/1,000PY; aHR 16.46; 95% CI 2.75-98.43) and cardiometabolic disease (1.12 vs. 0.14/1,000PY; aHR 4.32, 95% CI 1.73-10.79).

CONCLUSIONS

Swedish children and young adults with biopsy-confirmed NAFLD have significantly higher rates of overall, cancer-, liver- and cardiometabolic-specific mortality compared to matched general population controls.

LAY SUMMARY

Currently, the natural history and long-term risk of mortality in children and young adults with biopsy-confirmed non-alcoholic fatty liver disease (NAFLD) is unknown. This nationwide cohort study compared the risk of all-cause and cause-specific mortality in pediatric and young adult patients in Sweden with biopsy-confirmed NAFLD to matched general population controls. We found that compared to controls, children and young adults with biopsy-confirmed NAFLD and NASH have significantly higher rates of overall, cancer-, liver- and cardiometabolic-specific mortality.

Pattern and Prevalence of Liver Involvement in Pediatric Acute Lymphoblastic and Myeloid Leukemia at Diagnosis

OBJECTIVES

The prevalence and significance of liver involvement at diagnosis was studied in pediatric acute lymphoblastic (ALL) and myeloid leukemia (AML).

METHODS

A population based cohort of 122 pre B-ALL, 22 T-ALL and 45 AML patients was formed from the Nordic Society of Pediatric Hematology and Oncology leukemia registries (years 2005-2017). Hepatomegaly, elevated alanine aminotransferase, high INR, hypoalbuminemia and conjugated hyperbilirubinemia at diagnosis were used as markers for liver involvement. Minimal residual disease (MRD), time to relapse and overall survival (OS) were correlated with liver involvements.

RESULTS

The pattern of liver involvement was significantly different between leukemia subtypes (P = 0.025). The proportion of patients without liver abnormalities was 50.0% in AML and 44.8% in pre B-ALL and 23.5% in T-ALL patients. Hepatomegaly characterized lymphatic leukemia being present in 41.8% and 58.8% of pre B- and T-ALL patients. Liver dysfunction was most common in AML (29.5%) and least frequent in pre B-ALL (7.4%,) (P = 0.001). Conjugated hyperbilirubinemia was present in less than 5% of patients. Hepatomegaly correlated positively with age in pre B-ALL (P = 0.036) and white blood cell count (WBC) in AML (P = 0.010). Hepatic dysfunction was related with high WBC in pre B-ALL (P = 0.037) and AML (P = 0.001). Liver involvement in patients with ALL was not associated with toxicity or outcome. Patients with AML without liver involvement demonstrated superior OS.

CONCLUSIONS

Liver involvement is frequent at diagnosis in pediatric leukemia and its prevalence is related with leukemia subtype, age and WBC. In AML, but not in ALL, it associates with suboptimal prognosis.

Effects of odevixibat on pruritus and bile acids in children with cholestatic liver disease: Phase 2 study

PURPOSE

Ileal bile acid transporter inhibition is a novel therapeutic concept for cholestatic pruritus and cholestatic liver disease progression. Odevixibat, a potent, selective, reversible ileal bile acid transporter inhibitor, decreases enteric bile acid reuptake with minimal systemic exposure. Oral odevixibat safety, tolerability, and efficacy in pediatric patients with cholestatic liver disease and pruritus were evaluated.

PATIENTS AND METHODS

In this phase 2, open-label, multicenter study, children received 10‒200 μg/kg oral odevixibat daily for 4 weeks. Changes in serum bile acid levels (primary efficacy endpoint), pruritus, and sleep disturbance were explored.

RESULTS

Twenty patients were enrolled (8 females; 1‒17 years; 4 re-entered at a different dose). Diagnoses included progressive familial intrahepatic cholestasis (n = 13; 3 re-entries), Alagille syndrome (n = 6), biliary atresia (n = 3), and other intrahepatic cholestasis causes (n = 2; 1 re-entry). Mean baseline serum bile acid levels were high (235 µmol/L; range, 26‒564) and were reduced in the majority (-123.1 μmol/L; range, -394 to 14.5, reflecting reductions of up to 98%). Patient-reported diary data documented improved pruritus (3 scales) and sleep. With 100 μg/kg, mean (SEM) decrease was 2.8 (1.1) points for pruritus (visual analogue itch scale 0-10) and 2.9 (0.9) points for sleep disturbance (Patient-Oriented Scoring Atopic Dermatitis scale 0-10). Reduced pruritus correlated significantly with reduced serum bile acids (P ≤ 0.007). Significant correlations were also observed between autotaxin levels and pruritus. All patients completed the study. No serious adverse events were treatment related; most adverse events, including increased transaminases, were transient.

CONCLUSIONS

Orally administered odevixibat was well tolerated, reduced serum bile acids, and improved pruritus and sleep disturbance in children with cholestatic diseases.

Partial Biliary Diversion May Promote Long-Term Relief of Pruritus and Native Liver Survival in Children with Cholestatic Liver Diseases

INTRODUCTION

 Rare cholestatic liver diseases may cause debilitating pruritus in children. Partial biliary diversion (PBD) may relieve pruritus and postpone liver transplantation which is the only other alternative when conservative treatment fails. The aim was to report long-term outcome after PBD in a population of 26 million people during a 25-year period.

MATERIALS AND METHODS

 This is an international, multicenter retrospective study reviewing medical journals. Complications were graded according to the Clavien-Dindo classification system.

RESULTS

 Thirty-three patients, 14 males, underwent PBD at a median of 1.5 (0.3-13) years at four Nordic pediatric surgical centers. Progressive familial intrahepatic cholestasis was the most common underlying condition. Initially, all patients got external diversion, either cholecystojejunostomy (25 patients) or button placed in the gallbladder or a jejunal conduit. Early complications occurred in 14 (42%) patients, of which 3 were Clavien-Dindo grade 3. Long-term stoma-related complications were common (55%). Twenty secondary surgeries were performed due to stoma problems such as prolapse, stricture, and bleeding, or conversion to another form of PBD. Thirteen children have undergone liver transplantation, and two are listed for transplantation due to inefficient effect of PBD on pruritus. Serum levels of bile acids in the first week after PBD construction were significantly lower in patients with good relief of pruritus than in those with poor effect (13 [2-192] vs. 148 [5-383] μmol/L; p = 0.02).

CONCLUSION

 PBD may ensure long-term satisfactory effect on intolerable pruritus and native liver survival in children with cholestatic liver disease. However, stoma-related problems and reoperations are common.

Impact of Genotype, Serum Bile Acids, and Surgical Biliary Diversion on Native Liver Survival in FIC1 Deficiency

BACKGROUND AND AIMS

Mutations in ATPase phospholipid transporting 8B1 (ATP8B1) can lead to familial intrahepatic cholestasis type 1 (FIC1) deficiency, or progressive familial intrahepatic cholestasis type 1. The rarity of FIC1 deficiency has largely prevented a detailed analysis of its natural history, effects of predicted protein truncating mutations (PPTMs), and possible associations of serum bile acid (sBA) concentrations and surgical biliary diversion (SBD) with long-term outcome. We aimed to provide insights by using the largest genetically defined cohort of patients with FIC1 deficiency to date.

APPROACH AND RESULTS

This multicenter, combined retrospective and prospective study included 130 patients with compound heterozygous or homozygous predicted pathogenic ATP8B1 variants. Patients were categorized according to the number of PPTMs (i.e., splice site, frameshift due to deletion or insertion, nonsense, duplication), FIC1-A (n = 67; no PPTMs), FIC1-B (n = 29; one PPTM), or FIC1-C (n = 34; two PPTMs). Survival analysis showed an overall native liver survival (NLS) of 44% at age 18 years. NLS was comparable among FIC1-A, FIC1-B, and FIC1-C (% NLS at age 10 years: 67%, 41%, and 59%, respectively; P = 0.12), despite FIC1-C undergoing SBD less often (% SBD at age 10 years: 65%, 57%, and 45%, respectively; P = 0.03). sBAs at presentation were negatively associated with NLS (NLS at age 10 years, sBAs < 194 µmol/L: 49% vs. sBAs ≥ 194 µmol/L: 15%; P = 0.03). SBD decreased sBAs (230 [125-282] to 74 [11-177] μmol/L; P = 0.005). SBD (HR 0.55, 95% CI 0.28-1.03, P = 0.06) and post-SBD sBA concentrations < 65 μmol/L (P = 0.05) tended to be associated with improved NLS.

CONCLUSIONS

Less than half of patients with FIC1 deficiency reach adulthood with native liver. The number of PPTMs did not associate with the natural history or prognosis of FIC1 deficiency. sBA concentrations at initial presentation and after SBD provide limited prognostic information on long-term NLS.

Integration of whole genome sequencing into a healthcare setting: high diagnostic rates across multiple clinical entities in 3219 rare disease patients

BACKGROUND

We report the findings from 4437 individuals (3219 patients and 1218 relatives) who have been analyzed by whole genome sequencing (WGS) at the Genomic Medicine Center Karolinska-Rare Diseases (GMCK-RD) since mid-2015. GMCK-RD represents a long-term collaborative initiative between Karolinska University Hospital and Science for Life Laboratory to establish advanced, genomics-based diagnostics in the Stockholm healthcare setting.

METHODS

Our analysis covers detection and interpretation of SNVs, INDELs, uniparental disomy, CNVs, balanced structural variants, and short tandem repeat expansions. Visualization of results for clinical interpretation is carried out in Scout-a custom-developed decision support system. Results from both singleton (84%) and trio/family (16%) analyses are reported. Variant interpretation is done by 15 expert teams at the hospital involving staff from three clinics. For patients with complex phenotypes, data is shared between the teams.

RESULTS

Overall, 40% of the patients received a molecular diagnosis ranging from 19 to 54% for specific disease groups. There was heterogeneity regarding causative genes (n = 754) with some of the most common ones being COL2A1 (n = 12; skeletal dysplasia), SCN1A (n = 8; epilepsy), and TNFRSF13B (n = 4; inborn errors of immunity). Some causative variants were recurrent, including previously known founder mutations, some novel mutations, and recurrent de novo mutations. Overall, GMCK-RD has resulted in a large number of patients receiving specific molecular diagnoses. Furthermore, negative cases have been included in research studies that have resulted in the discovery of 17 published, novel disease-causing genes. To facilitate the discovery of new disease genes, GMCK-RD has joined international data sharing initiatives, including ClinVar, UDNI, Beacon, and MatchMaker Exchange.

CONCLUSIONS

Clinical WGS at GMCK-RD has provided molecular diagnoses to over 1200 individuals with a broad range of rare diseases. Consolidation and spread of this clinical-academic partnership will enable large-scale national collaboration.

Systematic Review and Meta-analysis: Partial External Biliary Diversion in Progressive Familial Intrahepatic Cholestasis

OBJECTIVES

We assessed available data on impact of partial external biliary diversion (PEBD) surgery on clinical outcomes in patients with progressive familial intrahepatic cholestasis (PFIC).

METHODS

We performed a systematic literature review (PubMed) and meta-analysis to evaluate relationships between liver biochemistry parameters (serum bile acids, bilirubin, and alanine aminotransferase [ALT]) and early response (pruritus improvement) or long-term outcomes (need for liver transplant) in patients with PFIC who underwent PEBD.

RESULTS

Searches identified 175 publications before September 2018; 16 met inclusion criteria. Receiver operating characteristic (ROC) analysis examined ability of liver biochemistry parameters to discriminate patients who demonstrated early and long-term response to PEBD from those who did not. Regarding pruritus improvement in 155 included patients in aggregate, 104 (67%) were responders, 14 (9%) had partial response, and 37 (24%) were nonresponders. In ROC analyses of individual patient data, post-PEBD serum concentration of bile acids, in particular, could discriminate responders from nonresponders for pruritus improvement (area under the curve, 0.99; P < 0.0001; n = 42); to a lesser extent, this was also true for bilirubin (0.87; P = 0.003; n = 31), whereas ALT could not discriminate responders from nonresponders for pruritus improvement (0.74; P = 0.06; n = 28). Reductions from pre-PEBD values in serum bile acid concentration (0.89; P = 0.0003; n = 32) and bilirubin (0.98; P = 0.002; n = 18) but not ALT (0.62; P = 0.46; n = 18) significantly discriminated decreased aggregate need for liver transplant.

CONCLUSION

Changes in bile acids seem particularly useful in discriminating early and long-term post-PEBD outcomes and may be potential biomarkers of response to interruption of enterohepatic circulation in patients with PFIC.

Genotype correlates with the natural history of severe bile salt export pump deficiency

BACKGROUND & AIMS

Mutations in ABCB11 can cause deficiency of the bile salt export pump (BSEP), leading to cholestasis and end-stage liver disease. Owing to the rarity of the disease, the associations between genotype and natural history, or outcomes following surgical biliary diversion (SBD), remain elusive. We aimed to determine these associations by assembling the largest genetically defined cohort of patients with severe BSEP deficiency to date.

METHODS

This multicentre, retrospective cohort study included 264 patients with homozygous or compound heterozygous pathological ABCB11 mutations. Patients were categorized according to genotypic severity (BSEP1, BSEP2, BSEP3). The predicted residual BSEP transport function decreased with each category.

RESULTS

Genotype severity was strongly associated with native liver survival (NLS, BSEP1 median 20.4 years; BSEP2, 7.0 years; BSEP3, 3.5 years; p <0.001). At 15 years of age, the proportion of patients with hepatocellular carcinoma was 4% in BSEP1, 7% in BSEP2 and 34% in BSEP3 (p = 0.001). SBD was associated with significantly increased NLS (hazard ratio 0.50; 95% CI 0.27-0.94: p = 0.03) in BSEP1 and BSEP2. A serum bile acid concentration below 102 μmol/L or a decrease of at least 75%, each shortly after SBD, reliably predicted NLS of ≥15 years following SBD (each p <0.001).

CONCLUSIONS

The genotype of severe BSEP deficiency strongly predicts long-term NLS, the risk of developing hepatocellular carcinoma, and the chance that SBD will increase NLS. Serum bile acid parameters shortly after SBD can predict long-term NLS.

LAY SUMMARY

This study presents data from the largest genetically defined cohort of patients with severe bile salt export pump deficiency to date. The genotype of patients with severe bile salt export pump deficiency is associated with clinical outcomes and the success of therapeutic interventions. Therefore, genotypic data should be used to guide personalized clinical care throughout childhood and adulthood in patients with this disease.

Practical management in Wolcott-Rallison syndrome with associated hypothyroidism, neutropenia, and recurrent liver failure: A case report

Wolcott‐Rallison syndrome is a rare genetic syndrome of neonatal diabetes, liver failure, and growth retardation. We present a case with a EIF2AK3 p.(Arg902Ter) mutation, additionally complicated by hypothyroidism, impaired renal function, and exocrine pancreas insufficiency, focusing on clinical management. For its optimization, thorough care of multiple organ systems is needed.

Altered peripheral amino acid profile indicate a systemic impact of active celiac disease and a possible role of amino acids in disease pathogenesis

BACKGROUND

We have previously performed a Genome Wide Association and linkage study that indicated a new disease triggering mechanism involving amino acid metabolism and nutrient sensing signaling pathways.

OBJECTIVE

The aim of this study was to investigate if plasma amino acid levels differed among children with celiac disease compared with disease controls.

MATERIALS AND METHODS

Fasting plasma samples from 141 children with celiac disease and 129 non-celiac disease controls, were analyzed for amino acid levels by liquid chromatography-tandem mass spectrometry (LC/MS). A general linear model using age and experimental effects as covariates was used to compare amino acid levels between children with a diagnosis of celiac disease and controls.

RESULTS

Seven out of twenty-three analyzed amino acids were elevated in children with celiac disease compared with controls (tryptophan, taurine, glutamic acid, proline, ornithine, alanine and methionine). The significance of the individual amino acids do not survive multiple correction, however, multivariate analyses of the amino acid profile showed significantly altered amino acid levels in children with celiac disease overall and after correction for age, sex and experimental effects (p = 8.4 × 10-8).

CONCLUSION

These findings support the idea that amino acids could influence systemic inflammation and play a possible role in disease pathogenesis.

Combining Rome III criteria with alarm symptoms provides high specificity but low sensitivity for functional gastrointestinal disorders in children

AIM

This study aimed to validate the Rome III criteria and alarm symptoms with regard to their ability to discriminate between organic and functional diagnoses in children with gastrointestinal complaints.

METHODS

We recruited 258 children aged four years to 17 years who consulted a paediatrician in secondary or tertiary care in Stockholm from January 2013 to May 2014 due to gastrointestinal complaints. A symptom questionnaire based on the official Questionnaire on Pediatric Gastrointestinal Symptoms Rome III, including questions on alarm symptoms, was used. A diagnostic review of their medical records was also carried out.

RESULTS

The reference diagnoses were organic (16%), pain-predominant functional gastrointestinal disorders (54%) and other functional diseases (30%). When the reported symptoms that fulfilled the Rome III criteria for pain-predominant functional gastrointestinal disorders were combined with an absence of alarm symptoms, they had a high specificity (0.90) for a functional diagnosis, but a low sensitivity (0.15). Alarm symptoms were equally common in patients with organic (83%) and functional diseases (80%, p = 0.66).

CONCLUSIONS

Combining the Rome III criteria and an absence of alarm symptoms from patient questionnaires had high specificity but low sensitivity when diagnosing pain-predominant functional gastrointestinal disorders in children seeking medical care for gastrointestinal complaints.

Complex Fluid Collection on Abdominal Ultrasound Indicates Need for Surgery in Neonates with Necrotizing Enterocolitis

Aim The aim of this study was to determine whether a correlation exists between the sonographic findings and the clinical outcomes, defined as surgery or death, in neonates with radiographically and/or histopathologically confirmed necrotizing enterocolitis (NEC). Material and Methods In this retrospective study, the case notes of 58 patients admitted to Karolinska University Hospital, Stockholm, Sweden, with radiographically confirmed NEC from September 2010 to August 2013, were reviewed. We included all newborns who underwent both plain abdominal radiographs and an abdominal ultrasound on the same day. The images were reviewed retrospectively. Patients' characteristics, clinical data, and histopathological data were recorded from the case notes. We excluded newborns who developed free gas before surgery. Abdominal ultrasound images were reviewed for free intraperitoneal gas, peritoneal fluid, pneumatosis intestinalis, portal gas, bowel vascularity, bowel wall thickness, and peristalsis. We correlated the sonographic features with the clinical outcomes; defined as the need for surgery or death. Results Overall, 25 neonates were included. Out of these, 11 patients underwent surgery and 5 patients died. The sonographic finding of complex fluid collection was statistically significant, predicting severe NEC that needed surgery. No other sonographic features were related to the need for surgery or death. Conclusion Complex fluid collection shown with abdominal ultrasound appears to be strongly correlated to the need for surgery in newborn infants with severe NEC.

Validity of histology for the diagnosis of paediatric coeliac disease: a Swedish multicentre study

OBJECTIVE Histological evaluation of intestinal biopsies for the diagnosis of coeliac disease can be challenging and compatible with risk of misdiagnosis. The aim was to evaluate the agreement of pathological diagnosis for coeliac disease in children investigated at four major paediatric university hospitals in Sweden. MATERIALS AND METHODS Intestinal duodenal biopsies were collected from 402 children at median 9.7 years (1.4-18.3 years). A pathologist at each hospital performed the primary evaluation. A designated pathologist, blinded to the primary evaluation, performed a second Marsh classification of biopsies (M0 to M3c) taken from the bulb and duodenum separately. Kappa (κ) scores between first and second evaluation determined the agreement. Plasma samples were collected at the day of intestinal biopsy and analysed for tissue transglutaminase autoantibodies (tTGA) using radioligand-binding assays. RESULTS Marsh scores were concordant in 229/356 biopsies (64%, κ = 0.52, p < 0.0001). Among discordant results, 15/127 (12%) showed M0 in distal duodenum but ≥ M2 in the bulb, whereas the opposite was true for 8/127 (6%) of the biopsies. There were fewer collected duodenal biopsies, more missing bulb biopsies and missing CD3 staining among discordant evaluations. The second evaluation revealed a Marsh score compliant with coeliac disease in 22 children of whom seven children were tTGA positive. CONCLUSIONS The variation between university hospitals on the pathological evaluation of biopsies may lead to misdiagnosis of coeliac disease in paediatric patients. Access to clinical and endoscopic information as well as tTGA levels may be useful for the pathologist to complement the evaluation in dubious cases.

Shared Genetic Factors Involved in Celiac Disease, Type 2 Diabetes and Anorexia Nervosa Suggest Common Molecular Pathways for Chronic Diseases

Background and Objectives

Genome-wide association studies (GWAS) have identified several genetic regions involved in immune-regulatory mechanisms to be associated with celiac disease. Previous GWAS also revealed an over-representation of genes involved in type 2 diabetes and anorexia nervosa associated with celiac disease, suggesting involvement of common metabolic pathways for development of these chronic diseases. The aim of this study was to extend these previous analyses to study the gene expression in the gut from children with active celiac disease.

Material and Methods

Thirty six target genes involved in type 2 diabetes and four genes associated with anorexia nervosa were investigated for gene expression in small intestinal biopsies from 144 children with celiac disease at median (range) age of 7.4 years (1.6–17.8) and from 154 disease controls at a median (range) age 11.4.years (1.4–18.3).

Results

A total of eleven of genes were differently expressed in celiac patients compared with disease controls of which CD36, CD38, FOXP1, SELL, PPARA, PPARG, AGT previously associated with type 2 diabetes and AKAP6, NTNG1 with anorexia nervosa remained significant after correction for multiple testing.

Conclusion

Shared genetic factors involved in celiac disease, type 2 diabetes and anorexia nervosa suggest common underlying molecular pathways for these diseases.

Genes involved in muscle contractility and nutrient signaling pathways within celiac disease risk loci show differential mRNA expression

Background

Risk gene variants for celiac disease, identified in genome-wide linkage and association studies, might influence molecular pathways important for disease development. The aim was to examine expression levels of potential risk genes close to these variants in the small intestine and peripheral blood and also to test if the non-coding variants affect nearby gene expression levels in children with celiac disease.

Methods

Intestinal biopsy and peripheral blood RNA was isolated from 167 children with celiac disease, 61 with potential celiac disease and 174 disease controls. Transcript levels for 88 target genes, selected from celiac disease risk loci, were analyzed in biopsies of a smaller sample subset by qPCR. Differentially expressed genes (3 from the pilot and 8 previously identified) were further validated in the larger sample collection (n = 402) of both tissues and correlated to nearby celiac disease risk variants.

Results

All genes were significantly down- or up-regulated in the intestinal mucosa of celiac disease children, NTS being most down-regulated (Fold change 3.6, p < 0.001). In contrast, PPP1R12B isoform C was up-regulated in the celiac disease mucosa (Fold change 1.9, p < 0.001). Allele specific expression of GLS (rs6741418, p = 0.009), INSR (rs7254060, p = 0.003) and NCALD (rs652008, p = 0.005) was also detected in the biopsies. Two genes (APPL2 and NCALD) were differentially expressed in peripheral blood but no allele specific expression was observed in this tissue.

Conclusion

The differential expression of NTS and PPP1R12B indicate a potential role for smooth muscle contractility and cell proliferation in celiac disease, whereas other genes like GLS, NCALD and INSR suggests involvement of nutrient signaling and energy homeostasis in celiac disease pathogenesis. A disturbance in any of these pathways might contribute to development of childhood celiac disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0190-1) contains supplementary material, which is available to authorized users.

A possible mechanism behind autoimmune disorders discovered by genome-wide linkage and association analysis in celiac disease

Celiac disease is a common autoimmune disorder characterized by an intestinal inflammation triggered by gluten, a storage protein found in wheat, rye and barley. Similar to other autoimmune diseases such as type 1 diabetes, psoriasis and rheumatoid arthritis, celiac disease is the result of an immune response to self-antigens leading to tissue destruction and production of autoantibodies. Common diseases like celiac disease have a complex pattern of inheritance with inputs from both environmental as well as additive and non-additive genetic factors. In the past few years, Genome Wide Association Studies (GWAS) have been successful in finding genetic risk variants behind many common diseases and traits. To complement and add to the previous findings, we performed a GWAS including 206 trios from 97 nuclear Swedish and Norwegian families affected with celiac disease. By stratifying for HLA-DQ, we identified a new genome-wide significant risk locus covering the DUSP10 gene. To further investigate the associations from the GWAS we performed pathway analyses and two-locus interaction analyses. These analyses showed an over-representation of genes involved in type 2 diabetes and identified a set of candidate mechanisms and genes of which some were selected for mRNA expression analysis using small intestinal biopsies from 98 patients. Several genes were expressed differently in the small intestinal mucosa from patients with celiac autoimmunity compared to intestinal mucosa from control patients. From top-scoring regions we identified susceptibility genes in several categories: 1) polarity and epithelial cell functionality; 2) intestinal smooth muscle; 3) growth and energy homeostasis, including proline and glutamine metabolism; and finally 4) innate and adaptive immune system. These genes and pathways, including specific functions of DUSP10, together reveal a new potential biological mechanism that could influence the genesis of celiac disease, and possibly also other chronic disorders with an inflammatory component.

Population-based study of incidence and clinical outcome of neonatal cholestasis in patients with Down syndrome

OBJECTIVE

To study the incidence and outcome of Down syndrome-associated neonatal cholestasis in a population-based cohort.

STUDY DESIGN

This retrospective study included all neonates diagnosed with Down syndrome born between January 2005 and September 2011 in the County of Stockholm, Sweden. Clinical and biochemical data related to cholestasis, early gastrointestinal (GI) involvement, congenital heart defects (CHD), and bone marrow disease were obtained from the computer-based hospital chart system.

RESULTS

A total of 206 newborns with Down syndrome were identified, for an incidence of 1 in 880 newborns. Prevalences of other diseases in these newborns included 47% for CHD, 11.2% for GI involvement, 3.9% for neonatal cholestasis, and 3.4% for bone marrow disease. Neonatal cholestasis was more common in the newborns with GI involvement (3 of 23 vs 5 of 183 of those without GI involvement; P = .047), CHD (8 of 96 vs 0 of 110 of those without CHD; P = .0019), and bone marrow disease (3 of 7 vs 5 of 199 of those without bone marrow disease; P = .0013). Cholestasis was severe in 3 patients (all of whom had bone marrow disease, with liver failure and early death in 2), and transient in 5 patients.

CONCLUSION

Neonatal cholestasis occurs in a significant percentage of patients with Down syndrome and is always associated with involvement of other organs. The outcome is variable, being most severe in newborns with the combination of neonatal cholestasis and bone marrow disease.

Hepatobiliary scintigraphy during cholestatic and noncholestatic periods in patients with progressive familial intrahepatic cholestasis after partial external biliary diversion

BACKGROUND

The purpose of the study was to determine the distribution of excreted bile during cholestatic periods and in remission in patients with progressive familial intrahepatic cholestasis (PFIC) after surgery with partial external biliary diversion (PEBD), using hepatobiliary scintigraphy.

METHODS

Using intravenously administered technetium Tc 99m-labeled mebrofenin, the distribution of bile during periods of biochemical cholestasis and in remission was investigated in patients with PFIC operated with PEBD. Stomal bile, urine, and feces from the patients were collected during 24 hours after administration of technetium Tc 99m-labeled mebrofenin; and the fractions of remaining radioactivity in the 3 compartments and the remaining isotopic activity in the body were quantified using scintigraphy.

RESULTS

Nine patients (4 boys and 5 girls) were studied. The median age was 13 (range, 5-24) years, and they had been operated with PEBD at a median time of 10 (range, 4-14) years before entering the study. Thirteen scintigraphic examinations were analyzed: 8 during noncholestatic remission (n = 7 patients) and 5 during cholestasis (n = 3 patients). The patients studied during remission discharged a significantly larger fraction of isotopic activity through the stoma (median, 90% vs 22%; P < .05) and a significantly lower fraction through the urine (median, 2.5% vs 15%; P < .05) compared with the patients studied during cholestasis.

CONCLUSION

Hepatobiliary scintigraphy could detect substantial differences in the output of bile. Further studies are needed to determine whether these differences may explain the mechanism of the PEBD operation or merely are secondary to the degree of cholestasis.

Follow-up in children with progressive familial intrahepatic cholestasis after partial external biliary diversion

OBJECTIVES

The aim of this study was to examine whether reversion of histological fibrosis followed partial external biliary diversion (PEBD) in patients with progressive familial intrahepatic cholestasis (PFIC); whether the duration of cholestatic episodes after PEBD influenced the evolution of fibrosis; and whether genotyping was helpful in predicting outcome of PEBD.

PATIENTS AND METHODS

Children with PFIC who underwent PEBD were investigated with genetic, biochemical, and anthropometric standard methods. Serial liver specimens were assessed histologically without knowledge of genotype and outcome. Findings were evaluated in the contexts of the total duration of cholestasis and the clinical outcome after PEBD.

RESULTS

From a total of 18 children with PFIC, 13 underwent PEBD, and 12 of these (among them 10 with identified ABCB11 mutations) were amenable for clinical and histological follow-up. When compared with baseline at PEBD, statistically significant reductions were found in histological cholestasis 1 and 3 years after PEBD, and in fibrosis 5 and >10 years after PEBD. The relative duration of cholestatic episodes after PEBD was positively correlated with the severity of fibrosis. Children homozygous for the missense mutation c.890A>G in ABCB11 responded well to PEBD.

CONCLUSIONS

Biliary diversion should be regarded as the first choice of surgical treatment in noncirrhotic patients with severe ABCB11 disease and may also be efficacious in other forms of PFIC.

Severe bile salt export pump deficiency: 82 different ABCB11 mutations in 109 families

BACKGROUND & AIMS

Patients with severe bile salt export pump (BSEP) deficiency present as infants with progressive cholestatic liver disease. We characterized mutations of ABCB11 (encoding BSEP) in such patients and correlated genotypes with residual protein detection and risk of malignancy.

METHODS

Patients with intrahepatic cholestasis suggestive of BSEP deficiency were investigated by single-strand conformation polymorphism analysis and sequencing of ABCB11. Genotypes sorted by likely phenotypic severity were correlated with data on BSEP immunohistochemistry and clinical outcome.

RESULTS

Eighty-two different mutations (52 novel) were identified in 109 families (9 nonsense mutations, 10 small insertions and deletions, 15 splice-site changes, 3 whole-gene deletions, 45 missense changes). In 7 families, only a single heterozygous mutation was identified despite complete sequence analysis. Thirty-two percent of mutations occurred in >1 family, with E297G and/or D482G present in 58% of European families (52/89). On immunohistochemical analysis (88 patients), 93% had abnormal or absent BSEP staining. Expression varied most for E297G and D482G, with some BSEP detected in 45% of patients (19/42) with these mutations. Hepatocellular carcinoma or cholangiocarcinoma developed in 15% of patients (19/128). Two protein-truncating mutations conferred particular risk; 38% (8/21) of such patients developed malignancy versus 10% (11/107) with potentially less severe genotypes (relative risk, 3.7 [confidence limits, 1.7-8.1; P = .003]).

CONCLUSIONS

With this study, >100 ABCB11 mutations are now identified. Immunohistochemically detectable BSEP is typically absent, or much reduced, in severe disease. BSEP deficiency confers risk of hepatobiliary malignancy. Close surveillance of BSEP-deficient patients retaining their native liver, particularly those carrying 2 null mutations, is essential.

Omitting control biopsy in paediatric coeliac disease: a follow-up study

AIM

To evaluate the practice of diagnosing coeliac disease with only one small-bowel mucosal biopsy in a selected group of children with suspected coeliac disease.

METHODS

A retrospective review of medical records and a follow-up interview of 102 children (65 girls, 37 boys) at diagnosis of coeliac disease. The inclusion criteria were age >18 months, increased levels of serum antitissue transglutaminase IgA antibodies and pathologic small-bowel mucosal biopsy. Anthropometric data were calculated for children 1.5-11 years of age.

RESULTS

The levels of serum antitissue transglutaminase IgA antibodies were either normal (92%) or slightly elevated (8%) in all children after 1 year on a gluten-free diet. The height-for-age Z score increased in 52 of 61 (85%) children, (median 0.26 SD, range -0.45 to 1.83 SD) and the weight-for-age Z score increased in 50 of 61 (82%) children (median 0.42 SD, range -0.77 to 2.24 SD). Sixty of 61 (98%) children showed normal or catch-up growth. Regression of symptoms after 1 year on a gluten-free diet was reported for 71 of 72 (98%) children.

CONCLUSION

We propose that a control biopsy is not necessary for the diagnosis of coeliac disease in these children.

Hepatocellular carcinoma in ten children under five years of age with bile salt export pump deficiency

Hepatocellular carcinoma (HCC) is rare in young children. We attempted to see if immunohistochemical and mutational-analysis studies could demonstrate that deficiency of the canalicular bile acid transporter bile salt export pump (BSEP) and mutation in ABCB11, encoding BSEP, underlay progressive familial intrahepatic cholestasis (PFIC)--or "neonatal hepatitis" suggesting PFIC--that was associated with HCC in young children. We studied 11 cases of pediatric HCC in the setting of PFIC or "neonatal hepatitis" suggesting PFIC. Archival liver were retrieved and immunostained for BSEP. Mutational analysis of ABCB11 was performed in leukocyte DNA from available patients and parents. Among the 11 nonrelated children studied aged 13-52 months at diagnosis of HCC, 9 (and a full sibling, with neonatal hepatitis suggesting PFIC, of a tenth from whom liver was not available) had immunohistochemical evidence of BSEP deficiency; the eleventh child did not. Mutations in ABCB11 were demonstrated in all patients with BSEP deficiency in whom leukocyte DNA could be studied (n = 7). These mutations were confirmed in the parents (n = 14). With respect to the other 3 children with BSEP deficiency, mutations in ABCB11 were demonstrated in all 5 parents in whom leukocyte DNA could be studied. Thirteen different mutations were found. In conclusion, PFIC associated with BSEP deficiency represents a previously unrecognized risk for HCC in young children. Immunohistochemical evidence of BSEP deficiency correlates well with demonstrable mutation in ABCB11.

Survey of unlicensed and off label drug use in paediatric wards in European countries. European Network for Drug Investigation in Children

OBJECTIVE

To determine the extent of use of unlicensed and off label drugs in children in hospital in five European countries.

DESIGN

Prospective study of drugs administered to children in general paediatric medical wards over four weeks.

SETTING

Children's wards in five hospitals (one each in the United Kingdom, Sweden, Germany, Italy, and the Netherlands).

SUBJECTS

Children aged 4 days to 16 years admitted to general paediatric medical wards.

MAIN OUTCOME MEASURE

Proportion of drugs that were used in an unlicensed or off label manner.

RESULTS

2262 drug prescriptions were administered to 624 children in the five hospitals. Almost half of all drug prescriptions (1036; 46%) were either unlicensed or off label. Of these 1036, 872 were off label and 164 were unlicensed. Over half of the patients (421; 67%) received an unlicensed or off label drug prescription.

CONCLUSIONS

Use of off label or unlicensed drugs to treat children is widespread. This problem is likely to affect children throughout Europe and requires European action.

Stargardt disease: linkage to the ABCR gene region on 1p21-p22 in Scandinavian families

Stargardt disease (STGD) or fundus flavimaculatus (FFM) is one of the most frequent causes of macular degeneration in childhood. The disease is inherited as an autosomal recessive trait and the corresponding gene has been localized to chromosome 1p21-22 and subsequently identified as the ATP-binding cassette transporter (ABCR) gene.

PURPOSE

To characterize Finnish and Swedish STGD families genetically, with special reference to chromosome region 1p21-22.

METHODS

We performed genetic linkage and haplotype analyses in five families of Finnish and Swedish origin with members affected by STGD or FFM.

RESULTS

Evidence for linkage between STGD and the ABCR gene region on chromosome 1p was found with a maximum cumulative two-point lod score for marker D1S188 (Z=4.04, theta=0.001). The affected individuals of all families, including the offspring of a consanguineous family, were found heterozygous for haplotypes spanning the ABCR gene.

CONCLUSION

The results support genetic homogeneity for a STGD/FFM gene defect on chromosome 1p21-22. A variety of haplotypes tightly linked to the ABCR gene region were found among affected individuals which indicate the presence of several independent STGD mutations in the Scandinavian population.

A gene encoding a liver-specific ABC transporter is mutated in progressive familial intrahepatic cholestasis

The progressive familial intrahepatic cholestases (PFIC) are a group of inherited disorders with severe cholestatic liver disease from early infancy. A subgroup characterized by normal serum cholesterol and gamma-glutamyltranspeptidase (gammaGT) levels is genetically heterogeneous with loci on chromosomes 2q (PFIC2) and 18q. The phenotype of the PFIC2-linked group is consistent with defective bile acid transport at the hepatocyte canalicular membrane. The PFIC2 gene has now been identified by mutations in a positional candidate, BSEP, which encodes a liver-specific ATP-binding cassette (ABC) transporter, sister of p-glycoprotein (SPGP). The product of the orthologous rat gene has been shown to be an effective bile acid transporter in vitro. These data provide evidence that SPGP is the human bile salt export pump (BSEP).

Progressive familial intrahepatic cholestasis (PFIC): evidence for genetic heterogeneity by exclusion of linkage to chromosome 18q21-q22

Progressive familial intrahepatic cholestasis (PFIC) is the second most common form of familial intrahepatic cholestasis. The genes for PFIC and for a milder form of the disease, benign recurrent intrahepatic cholestasis (BRIC), were recently mapped to a 19-cM region on chromosome 18q21-q22. The results suggest that PFIC and BRIC are allelic diseases. We have studied 11 Swedish patients from eight families with clinical and biochemical features consistent with PFIC. The families were genotyped for markers D18S69, D18S64, D18S55 and D18S68, spanning the PFIC candidate region. Unexpectedly, the segregation of haplotypes excluded the entire region in three families, and no indications for shared haplotypes were found in the patients of the six remaining families. A four-point linkage analysis of all families excluded linkage from D18S69 to D18S55 (Zmax < -5). Thus, our data strongly suggest the presence of a second, yet unknown, locus for PFIC. The results indicate that great care should be taken when using 18q markers for prenatal diagnosis and genetic counseling for the disease.

The genetics of primary nocturnal enuresis: inheritance and suggestion of a second major gene on chromosome 12q

Primary nocturnal enuresis (PNE), or bedwetting at night, affects approximately 10% of 6 year old children. Genetic components contribute to the pathogenesis and recently one locus was assigned to chromosome 13q. We evaluated the genetic factors and the pattern of inheritance for PNE in 392 families. Dominant transmission was observed in 43% and an apparent recessive mode of inheritance was observed in 9% of the families. Among the 392 probands the ratio of males to females was 3:1 indicating sex linked or sex influenced factors. Linkage to candidate regions was tested in 16 larger families segregating for autosomal dominant PNE. A gene for PNE was excluded from chromosome 13q in 11 families, whereas linkage to the interval D13S263-D13S291 was suggested (Zmax = 2.1) in three families. Further linkage analyses excluded about 1/3 of the genome at a 10 cM resolution except the region around D12S80 on chromosome 12q that showed a positive two point lod score in six of the families (Zmax = 4.2). This locus remains suggestive because the material was not sufficiently large to give evidence for heterogeneity. Our pedigree analysis indicates that major genes are involved in a large proportion of PNE families and the linkage results suggest that such a gene is located on chromosome 12q.

An echocardiographic study comparing male Swedish elite orienteers with other elite endurance athletes

Between 1979 and 1992, there were 16 known cases of sudden unexpected cardiac death among young Swedish orienteers, whose autopsies showed myocarditis to be a common finding. Therefore, 96 elite orienteers and 47 controls underwent echocardiography, showing left ventricular wall motion abnormalities in 9% of the orienteers compared with 4% in the controls.

Anticipation of autosomal dominant progressive external ophthalmoplegia with hypogonadism

A large Swedish family with members affected by progressive external ophthalmoplegia with hypogonadism were followed-up and reviewed. Hypogonadism included delayed sexual maturation, primary amenorrhea, early menopause, and testicular atrophy. Cataracts, cerebellar ataxia, neuropathy, hypoacusia, pes cavus, tremor, parkinsonism, depression, and mental retardation were other features observed in this family. Muscle biopsy samples of advanced cases showed ragged-red fibers, focal cytochrome c oxidase deficiency, and multiple mtDNA deletions by Southern blot analysis. An autosomal dominant mode of inheritance was evident with anticipation in successive generations. Linkage analysis excluded the chromosome 10q23.3-q24.3 region reported as being linked to the disease in a Finnish family with autosomal dominant progressive external ophthalmoplegia. We report for the first time clinical evidence for anticipation in a family with autosomal dominant progressive external ophthalmoplegia. We hypothesize that the nuclear gene causing this enigmatic disorder may be directly influenced by an expansion of an unstable DNA sequence and that the resulting phenotype is caused by a concerted action with multiple deletions of mtDNA.

Growth and pubertal development in Down syndrome

Growth retardation and gonadal insufficiency are well-known features of Down syndrome. In this longitudinal study, 44 home-reared children and adolescents with Down syndrome, aged 10-24 years, living in the county of Uppsala, were followed yearly. The male patients had a mean final height above that reported previously, and a close correlation between target and final heights was found. The mean final height in the female patients was below that reported earlier. Mean peak height velocities in males and females were 8.5 and 7.3 cm year-1, respectively, significantly lower than in healthy children. The mean ages at peak height velocity were 12.3 and 10.8 years, respectively, indicating early growth spurts. The serum follicle-stimulating hormone concentrations, the small testes and the negative correlation between luteinizing hormone and testicular volume in the males may indicate some primary gonadal insufficiency. For the girls, mean menarcheal age corresponded closely to that of their mothers.

Echocardiographic right and left ventricular measurements in male elite endurance athletes

Echocardiography was used to assess normal values in the right and left ventricular cavity and wall in 127 male elite endurance athletes. M-mode and two dimensional measurements of left ventricle and left and right atria were also obtained. All subjects were high-performance orienteers, cross-country skiers and middle-distance runners. They all had a normal electrocardiogram at rest and no echocardiographic evidence of heart disease. With the use of multiple right ventricular cross-sections and two-dimensional measurements, we found a significantly greater right ventricular inflow tract and right and left atrial measurements in endurance athletes compared with earlier studies of normal, active subjects. The right ventricular free wall was slightly thicker than reported in normal active subjects but the differences were small. Left ventricular diastolic diameter was consistent with previous reports of endurance athletes. Of the 127 subjects, 13% had left ventricular wall thickness above 13 mm but none of the athletes had wall thickness above 15 mm. These data suggest that cardiac enlargement occurs symmetrically in both right and left cavities, probably reflecting increased haemodynamic loading, a mechanism by which athletes sustain a high cardiac output during exercise.