Novel mutations in TTC37 associated with tricho-hepato-enteric syndrome.

The Tricho-Hepato-Enteric (THE) syndrome is an autosomal recessive condition marked by early and intractable diarrhea, hair abnormalities, and immune defects. Mutations in TTC37, which encodes the putative protein Thespin, have recently been associated with THE syndrome. In this article, we extend the pattern of TTC37 mutations by the description of 11 novel mutations in 9 patients with a typical THE syndrome. The mutations were spread along the gene sequence, none of themrecurrent. Different types of mutation were observed: frameshift mutations, splice-site altering mutations, or missense mutations, most of them leading to the creation of a premature stop codon. Concurrently, we investigated the pattern of TTC37 expression in a panel of normal human tissues and showed that this gene is widely expressed, with high levels in vascular tissues, lymph node, pituitary, lung, and intestine. In contrast, TTC37 is not expressed in the liver, an organ that is not consistently affected in THE syndrome. Last, we suggested a model for the putative structure of the unknown Thespin protein.

Exclusion of EGFR, HRAS, DSP, JUP, CTNNB1, PLEC1, and EPPK1 as functional candidate genes in 7 families with syndromic diarrhoea.

Syndromic diarrhoea (SD) is a rare disease associating intractable diarrhoea and hair abnormalities. In an attempt to identify the gene causative for SD, we studied several functional candidate genes, based on their implication in overlapping phenotypes in mice (EGFR) or in humans (HRAS, JUP, DSP EPPK1, PLEC1, and CTNNB1) in 8 patients affected by SD. Except for EGFR and HRAS, all selected genes encode for cell adhesion proteins. Using direct sequencing or linkage analysis, we excluded all of the candidate genes as the disease-causing gene in our group of patients; however, the hypothesis of intercellular junctions defect in SD remains seductive.

12-month follow-up after successful infliximab therapy in pediatric crohn disease.

AIM: Infliximab (IFX) therapy is highly efficacious for the induction and maintenance of remission in pediatric Crohn disease (CD). However, to date it is unclear how long patients should be given IFX. Given the increasing safety concerns about the concomitant and prolonged use of IFX and azathioprine in CD, we wanted to address the clinical outcome in pediatric CD patients who responded to IFX medication, once IFX was stopped. PATIENTS AND METHODS: Upon induction therapy with 3 IFX infusions, 36 of 38 patients with CD were in clinical remission at 3 months. These 36 responders were separated into 2 groups: 16 patients received no further IFX infusions, whereas 20 patients received scheduled maintenance therapy with IFX for 12 months. RESULTS: Among the 16 patients who received no further IFX infusions, 12 experienced relapse during the 12-month follow-up interval after IFX was stopped. In the group receiving maintenance therapy, 11 of 20 patients remained in clinical remission at 12 months of therapy, whereas 8 patients required adjustment of IFX doses or intervals. Among the 11 children who were in clinical remission and receiving maintenance therapy without dose adjustment, 8 experienced relapse within 12 months after IFX maintenance therapy was stopped. Overall, the relapse rates after IFX induction or maintenance therapy was stopped were 75% and 72%, respectively. CONCLUSIONS: These data indicate that IFX is efficacious in controlling severe pediatric CD; however, to induce and maintain clinical remission, repeated IFX infusions are required, with a need for dose adjustment in a substantial number of patients.

Crohn's disease: the cold chain hypothesis.

Crohn's disease is the result of an abnormal immune response of the gut mucosa triggered by one or more environmental risk factors in people with predisposing gene variations, including CARD15 mutations. Epidemiological data allow assessment of familial environmental risk factors related to western lifestyle, diet, bacteria, and domestic hygiene. All findings point to refrigeration as a potential risk factor for Crohn's disease. Furthermore, cold-chain development paralleled the outbreak of Crohn's disease during the 20th century. The cold chain hypothesis suggests that psychrotrophic bacteria such as Yersinia spp and Listeria spp contribute to the disease. These bacteria have been identified in Crohn's disease lesions and we discuss their pathogenic properties with respect to our knowledge of the disease. From a molecular perspective, we postulate that the disease is a result of a defect in host recognition by pathogenic bacterial components that usually escape the immune response (eg, Yop molecules), which results in an excessive host response to these bacteria.

Ileal involvement is age dependent in pediatric Crohn's disease.

BACKGROUND: Lymphoid follicles (LFs) have been suggested to play a role at the early stage of Crohn's disease (CD) lesions. In the small bowel, LFs are grouped, forming Peyer's patches, which develop early in fetal life, grow in size and number until puberty, and undergo involution. In contrast, colonic LFs are isolated and undergo little change during life. As a result, if LFs play a role in the occurrence of CD lesions, the distribution of ileal and colonic lesions is expected to be altered in small children. METHODS: Medical records of 2 independent French (n = 136) and Swedish (n = 55) cohorts of consecutive pediatric CD were reviewed. Disease sites and age of onset were recorded, and the age-dependent probability to develop ileal lesions was computed. The CARD15/NOD2 genotype was also analyzed when available (n = 99). RESULTS: The curves of disease occurrence were significantly different in case of CD with or without ileal lesions (P < 0.0001). At the age of 8 years, the probability (95% confidence interval) of small bowel involvement was 0.19 (0.07-0.39). It increased until 16 years of age to 0.61 (0.54-0.68). It was slightly higher in patients carrying 1 or more CARD15/NOD2 mutations [0.75 (0.55-0.89)] than in wild-type patients [0.46 (0.34-0.58)]. CARD15 mutations also influenced the age of onset of ileal disease (P < 0.02). CONCLUSIONS: In children, ileal CD lesions are delayed compared with colonic lesions. This observation is in agreement with the previously proposed hypothesis of a pathophysiological role of Peyer's patches in ileal CD. The rarity of small bowel lesions should be a warning to be cautious when classifying chronic colitis in small children.

Clustering of Crohn's disease within affected sibships.

Crohn's disease (CD) is a complex genetic disorder for which aetiology is unknown. Recently, genetic factors for susceptibility have been described. Several genetic loci have been mapped and partially explain the familial aggregations of the disease. However, environmental factors may also contribute to these aggregations. We considered that if the role of non-genetic factors was negligible, CD patients would be randomly distributed in sibships with multiple affected siblings. On the other hand if there was a significant environmental contribution, the siblings would be affected non-randomly over exposure status. In order to test this hypothesis, we studied 102 sibships with two or more affected siblings. A statistical test, named Cluster of Affected Sibling Test or CAST, was developed, based on the exact calculation of the probability of observing a given number of clusters of affected siblings in multiplex families. The null hypothesis of a random distribution of affected siblings was rejected (P=0.005). The observed excess of affected sibling clusters indicates that birth order influences the disease status. Considering that an adjacent order of birth is a global estimate of environmental sharing, this observation strongly suggests that environmental factors contribute to the observed familial aggregations of the disease. This observation provides evidence that familial CD is a relevant tool for further studies of environmental factors and gene-environment interaction. More generally, the CAST statistics may be widely applicable to estimate the involvement of environmental factors in the aetiology of other binary traits which may be observed in multiple members of the same sibship.

Centrilobular necrosis in children after combined liver and small bowel transplantation.

BACKGROUND: Centrilobular necrosis is not an uncommon finding after isolated liver transplantation. In this study, we sought to describe hepatic centrilobular necrosis in children after combined liver and small bowel transplantation (LSBT), and to assess the predictive factors, possible causes, and prognosis. METHODS: Six children aged 4 to 11 years, in whom liver biopsy showed centrilobular necrosis at least once, 3 weeks to 2 years after LSBT, were compared with nine children without this pathology. All six children experienced an acute complication in the few weeks preceding the finding of centrilobular necrosis. In addition, one child had an early arterial thrombosis and one, severe colitis 3 years after LSBT. RESULTS: Centrilobular necrosis was associated with centrilobular swelling, dropout, endotheliitis, and inflammation. Fibrosis developed early and worsened on follow-up biopsy in three children. Portal symptoms of acute rejection were not constant, and there was no ductopenia. Biologic abnormalities were responsive to increased immunosuppression, including mycophenolate in four cases. However, follow-up biopsies showed persistent lesions in five patients, mildly inflammatory in four. Baseline immunosuppression had to be maintained at high levels. No viral infections, vascular compromise (except in one), and autoimmunity were found. We compared the two groups of children for initial diagnosis, age at transplantation, time receiving parenteral nutrition, ischemic time, presence of an associated transplanted colon, number of reoperations and infections, intestinal rejection, and immunosuppression, and found no differences. CONCLUSIONS: This severe manifestation of chronic liver rejection occurred despite the heavy immunosuppression needed for LSBT. The previous acute clinical event could have triggered rejection by modifying the effective immunosuppression at the tissue level. Despite high baseline immunosuppression, histologic lesions persisted and significant fibrosis developed in half the children. We speculate that the lack of induction of tolerance in this particular setting of LSBT could be responsible for constant immune stimulation, thus chronic rejection. The optimal protocol of immunosuppression has yet to be defined to avoid this complication.

New perspectives for children with microvillous inclusion disease: early small bowel transplantation.

BACKGROUND: Microvillous inclusion disease (MVID) is a congenital intestinal epithelial cell disorder leading to lifelong intestinal failure. Despite long-term total parenteral nutrition, life expectancy is extremely reduced because of metabolic or septic complications or liver failure. METHODS: Twelve patients with early-onset MVID were evaluated between 1995 and 2002 for the possibility of small bowel transplantation (SbTx). Three patients died before they could be placed on the waiting list for SbTx, and one patient is still awaiting SbTx. SbTx was contraindicated in one patient. RESULTS: Seven of 12 patients (six boys and one girl) underwent transplantation (three SbTxs and four combined liver-SbTxs). Actuarial survival rates were 100% and 75% in the SbTx and combined liver-SbTx groups, respectively, with a mean follow-up of 3 years (1.1-8.5 years). In contrast, the survival rate was only 40% in the subgroup of five patients who did not undergo transplantation. After transplantation, all patients were weaned from parenteral nutrition: the five patients with an additional colon graft were weaned within 36 days as opposed to the others without colonic transplant who obtained full intestinal autonomy several months after transplantation. The only two surviving patients who did not undergo SbTx remain highly dependent on total parenteral nutrition, which is complicated by repeated episodes of metabolic decompensation. CONCLUSIONS: SbTx alone or in combination with the liver is highly successful in children with MVID, offering them a long-term perspective for the first time. Associated colon grafting markedly improves the outcome and quality of life after SbTx in patients with MVID.

Efficacy and tolerance of infliximab in children and adolescents with Crohn's disease.

Infliximab, a monoclonal antibody against tumor necrosis factor-alpha, has been shown to be effective for the treatment of refractory Crohn's disease in adult patients, but experience in pediatrics is limited. This retrospective study included 88 children and adolescents, 39 girls and 49 boys, with a median age of 14 years (range 3.3-17.9). Infliximab was indicated for active disease (66%) and/or fistulas (42%) that were refractory to corticosteroids (70%), and/or other immunosuppressive (82%) agents, and/or parenteral nutrition (20%). Patients received 1 to 17 infusions (median 4) of 5 mg/kg (range 3.8-7.3) of infliximab during a median time period of 4 months (1-17 months). Infusion reaction was noted in 13 patients (15%), with a total of 16 reactions in 450 infusions (4%). At Day 90 after the first infusion of infliximab, symptoms improved in 49% of patients, whereas 29% of patients were in remission and 13% of patients relapsed. From Day 0 to Day 90, Harvey-Bradshaw score decreased from 7.5 to 2.8 (P < 0.001), C-reactive protein from 36 to 16 mg/L (P < 0.01), and 1-hour erythrocyte sedimentation rate from 35 to 17 mm (P < 0.01). Dosage of corticosteroids decreased from to 0.59 to 0.17 mg/kg/d (P < 0.001); 53% of patients could be weaned of corticosteroids and 92% of parenteral nutrition. Treatment with infliximab is well tolerated and effective in most children and adolescents with Crohn's disease that is refractory to conventional immunosuppressive therapy. Nevertheless, long-term efficacy remains to be shown, and further studies are urgently needed to precisely determine the best modality of continuing treatment.

Genotype/phenotype analyses for 53 Crohn's disease associated genetic polymorphisms.

BACKGROUND & AIMS: Recent studies reported a role for more than 70 genes or loci in the susceptibility to Crohn's disease (CD). However, the impact of these associations in clinical practice remains to be defined. The aim of the study was to analyse the relationship between genotypes and phenotypes for the main 53 CD-associated polymorphisms. METHOD: A cohort of 798 CD patients with a median follow up of 7 years was recruited by tertiary adult and paediatric gastroenterological centres. A detailed phenotypic description of the disease was recorded, including clinical presentation, response to treatments and complications. The participants were genotyped for 53 CD-associated variants previously reported in the literature and correlations with clinical sub-phenotypes were searched for. A replication cohort consisting of 722 CD patients was used to further explore the putative associations. RESULTS: The NOD2 rare variants were associated with an earlier age at diagnosis (p = 0.0001) and an ileal involvement (OR = 2.25[1.49-3.41] and 2.77 [1.71-4.50] for rs2066844 and rs2066847, respectively). Colonic lesions were positively associated with the risk alleles of IL23R rs11209026 (OR = 2.25 [1.13-4.51]) and 6q21 rs7746082 (OR = 1.60 [1.10-2.34] and negatively associated with the risk alleles of IRGM rs13361189 (OR = 0.29 [0.11-0.74]) and DEFB1 rs11362 (OR = 0.50 [0.30-0.80]). The ATG16L1 and IRGM variants were associated with a non-inflammatory behaviour (OR = 1.75 [1.22-2.53] and OR = 1.50 [1.04-2.16] respectively). However, these associations lost significance after multiple testing corrections. The protective effect of the IRGM risk allele on colonic lesions was the only association replicated in the second cohort (p = 0.03). CONCLUSIONS: It is not recommended to genotype the studied polymorphisms in routine practice.

Racecadotril for childhood gastroenteritis: an individual patient data meta-analysis.

BACKGROUND: Racecadotril is an antidiarrhoeal drug with intestinal antisecretory mechanism of action. AIM: To assess racecadotril efficacy as an adjunct to oral rehydration solution, against oral rehydration solution alone or with placebo in childhood acute gastroenteritis. METHODS: Individual patient data meta-analysis following multilevel mixed models testing the significance of the treatment effect adjusted for baseline covariates. RESULTS: Nine randomised clinical trials (n=1384) were identified with raw data. Baseline dehydration level and Rotavirus were found as two essential predictors influencing the outcomes. The proportion of recovered patients was higher in racecadotril groups compared with placebo, Hazard Ratio HR=2.04, 95% CI (1.85; 2.32), p<0.001. For inpatient studies, the ratio of mean stool output racecadotril/placebo was 0.59 (0.51; 0.74), p<0.001. For outpatient studies, the ratio of the mean number of diarrhoeic stools racecadotril/placebo was 0.63 (0.51; 0.74), p<0.001. CONCLUSION: Dehydration level and Rotavirus at baseline are essential adjustments to compare treatments. As an adjunct to oral rehydration solution, racecadotril has a clinically relevant effect in reducing diarrhoea (duration, stool output and stool number), irrespective of baseline conditions (dehydration, Rotavirus or age), treatment conditions (inpatient or outpatient studies) or cultural environment.

Efficacy of infliximab in pediatric Crohn's disease: a randomized multicenter open-label trial comparing scheduled to on demand maintenance therapy.

BACKGROUND: Infliximab (IFX) is efficacious in inducing remission in severe forms of pediatric Crohn's disease (CD). Adult studies indicate that IFX is also safe and well tolerated as maintenance therapy. The present study aimed to evaluate in a prospective manner the efficacy and safety of IFX as maintenance therapy of severe pediatric CD comparing scheduled and "on demand" treatment strategies. METHODS: Forty children with CD (nonpenetrating, nonstricturing as well as penetrating forms, mean age: 13.9 +/- 2.2 years) with a severe flare-up (Harvey-Bradshaw Index [HBI] > or =5, erythrocyte sedimentation rate [ESR] >20 mm/h) despite well-conducted immunomodulator therapy (n = 36 azathioprine, n = 1 mercaptopurine, n = 3 methotrexate) combined with steroids were included in this randomized, multicenter, open-label study. Three IFX infusions (5 mg/kg) were administered at week (W)0/W2/W6. At W10, clinical remission (HBI <5) and steroid withdrawal were analyzed and IFX responders were randomized to maintenance therapy over 1 year: group A, scheduled every 2 months; group B, "on demand" on relapse. RESULTS: In all, 34/40 children came into remission during IFX induction therapy (HBI: 6.7 +/- 2.5 (WO) vs. 1.1 +/- 1.5 (W10); P < 0.001). At the end of phase 2, 15/18 (83%) patients were in remission in group A compared to 8/13 (61%) children in group B (P < 0.01), with a mean HBI of 0.5 versus 3.2 points (group A versus B, P = 0.011). In group A, 3/13 (23.1%) children experienced a relapse compared to 11/12 (92%) children in group B. No severe adverse event occurred during this trial. CONCLUSIONS: IFX is well tolerated and safe as maintenance therapy for pediatric CD, with a clear advantage when used on a scheduled 2-month basis compared to an "on demand" basis.

Syndromic (phenotypic) diarrhea in early infancy.

Syndromic diarrhea (SD), also known as phenotypic diarrhea (PD) or tricho-hepato-enteric syndrome (THE), is a congenital enteropathy presenting with early-onset of severe diarrhea requiring parenteral nutrition (PN). To date, no epidemiological data are available. The estimated prevalence is approximately 1/300,000-400,000 live births in Western Europe. Ethnic origin does not appear to be associated with SD. Infants are born small for gestational age and present with facial dysmorphism including prominent forehead and cheeks, broad nasal root and hypertelorism. Hairs are woolly, easily removed and poorly pigmented. Severe and persistent diarrhea starts within the first 6 months of life (

Intestinal transplantation for total intestinal aganglionosis: a series of 12 consecutive children.

BACKGROUND: Management of patients with total intestinal aganglionosis (TIA) is a medical challenge because of their dependency on parenteral nutrition (PN). Intestinal transplantation (ITx) represents the only alternative treatment for patients with irreversible intestinal failure for achieving intestinal autonomy. METHODS: Among 66 patients who underwent ITx in our center, 12 had TIA. They received either isolated ITx (n = 4) or liver-ITx (LITx, n = 8) after 10 to 144 months of total PN. All grafts included the right colon. RESULTS: After a median follow-up of 57 months, the survival rate was 62.5% in the LITx group and 100% in the ITx patients. The graft survival rate was 62.5% in the LITx group and 75% in the ITx group. All the surviving patients were fully weaned from total PN, after a median of 57 days. Pull through of the colon allograft was carried out in all patients. Fecal continence is normal in all but one of the surviving children. CONCLUSION: These results suggest that ITx with colon grafting should be the preferred therapeutic option in TIA. Early referral to a transplantation center after diagnosis of TIA is critical to prevent PN-related cirrhosis and thereby to permit ITx, which is associated with a good survival rate.

Clinical and biological consequences of immunization to infliximab in pediatric Crohn's disease.

Tumor necrosis factor (TNF)-alpha plays a critical role in the initiation and progression of Crohn's disease, a chronic inflammatory disorder of the gastrointestinal tract. Infliximab, a chimeric monoclonal antibody blocking TNF-alpha, has proven effective as an induction and maintenance therapy for refractory Crohn's disease in adult and pediatric patients. However, infliximab therapy induces the appearance of neutralizing anti-infliximab antibodies. In the pediatric cohort, we analyzed (n=28) sensitization occurred in 35.7% patients and was associated with a loss of response to maintenance infusions. In two patients presenting high titers of anti-infliximab antibodies, severe infusion reactions were observed, possibly IgE-mediated, precluding further use of the medication. Serum concentrations of TNF-alpha and infliximab were influenced by the presence of anti-infliximab antibodies. We propose that surveillance of circulating infliximab and/or TNF-alpha concentration during maintenance therapy represents an indirect but reliable method to monitor anti-infliximab immunization.

CARD15/NOD2 is not a predisposing factor for necrotizing enterocolitis.

Multiple factors are incriminated in the etiopathogeny of necrotizing enterocolitis (NEC) in premature infants, including oral feeding, vascular abnormalities, increase in pro-inflammatory cytokines, and inappropriate response of the intestinal barrier to bacterial microflora. CARD15/NOD2 is a gene recently recognized as important in the innate response to gut flora and is involved in Crohn's disease susceptibility. We thus tested its putative role in NEC. Ten children (seven boys and three girls) suffering from NEC who were admitted to Robert Debré hospital between 1999 and 2002 were retrospectively included in the study. Genetic screening of the 11 constant exons and the exon-intron junctions of CARD15/NOD2 by direct sequencing revealed no novel mutations of that gene in NEC patients. Furthermore, the three main mutations of CARD15/NOD2 (R702W, G908R, and 1007fs) associated with susceptibility to Crohn's disease were not found in these patients. Our results suggest that CARD15/NOD2 does not play a major role in genetic susceptibility to NEC.

Managing gastro-oesophageal reflux disease in children.

Gastro-oesophageal reflux (GOR) and gastro-oesophageal reflux disease (GORD) have a higher prevalence among infants than among children or adults. This is linked to the immaturity of the oesophagus and stomach and the higher liquid intake of infants. Genetic factors could also be contributory in some families. Clinical symptoms in infants are mainly regurgitation and vomiting, which usually disappear between 1 and 3 years of age. Symptoms in children are similar to those in adults. Treatment in children depends on age and GORD severity. With GOR or mild GORD, particularly in infants, explanation and reassurance together with thickening of formula feed and lifestyle changes are usually effective. Prokinetics either have unproven efficacy (metoclopramide, domperidone) or have been withdrawn (cisapride). Chronic antacid therapy is not recommended. In moderate to severe GORD, histamine-2-receptor antagonists and particularly proton pump inhibitors (PPIs) are effective, especially when oesophagitis is present. PPIs, in particular omeprazole and lansoprazole, have proven efficacy in infants and children. They are well tolerated, with pharmacokinetics similar to those in adults. However, dosages should be adapted in neonates and children under 10 years old. Fundoplication should be avoided before 2 to 3 years of age if possible.

A prospective study of the efficacy and tolerance of a chimeric antibody to tumor necrosis factors (remicade) in severe pediatric crohn disease.

OBJECTIVES: To evaluate the efficacy and toxicity of infliximab in children with severe Crohn disease (CD), the authors prospectively monitored 21 children aged 15 +/- 2 years with severe CD who they treated with infliximab (5 mg/kg) on days 0, 15, and 45. One patient received only one injection. Eighteen patients were corticosteroid dependent, and 6 were receiving parenteral nutrition. Three patients were corticoid resistant (1 mg/kg/d >15 days). Sixteen had perianal disease. RESULTS: The Harvey-Bradshaw index (HB) decreased from 8 +/- 3 on day 0 to 1 +/- 2 on day 45 (P = 0.001). The inflammation factors decreased (P = 0.001), and albumin increased (P = 0.002). Nineteen children were in complete remission (HB < 4) on day 45, and 2 had improved (HB = -6 points). Tumor necrosis factor-alpha (TNFalpha) in the stools (n = 16) decreased (P = 0.04). All perianal fistulas (n = 12) were closed by day 90. Fourteen of 21 patients had stopped taking steroids at 3 months, and all had stopped parenteral nutrition. Growth velocity was significantly greater after infliximab administration (Z score, +0.5) than before (-0.45; P = 0.004). Nineteen of 21 patients had relapsed (90%) at 1 year despite continued immunosuppressors. Seven had surgery because of an uncontrolled relapse ( 5), stenosis ( 1), or fistula ( 1). Six patients developed antinuclear antibodies (1/40-1/640e), and two had anti-DNA antibodies. Epstein-Barr virus (EBV) polymerase chain reaction (PCR) values increased (>100-fold) in eight patients. One child developed an anaphylactic reaction to the medication, and one had a catheter-related sepsis. CONCLUSION: Infliximab produces spectacular results for children with severe CD and is well tolerated. However, its effect is transitory for many (90%), with frequent relapses despite continued immunosuppressors. Long-term management with infliximab should be tested despite its worrying side effects.

Total energy expenditure and physical activity in children treated with home parenteral nutrition.

Determining total energy expenditure (TEE) and its components in children treated with home parenteral nutrition (CHPN) under free-living conditions is an important consideration in the assessment of energy requirements and the maintenance of health. The aim of this study was to assess TEE and physical activity in CHPN. Eleven CHPN (three girls and eight boys; median age, 6.0 y; range, 4.5-15.0 y) were compared with 11 healthy children (three girls and eight boys; median age, 6.0 y, range, 4.5-14.0 y) after pairing for sex, age, and weight. Underlying diseases included chronic intractable diarrhea (n = 5), short bowel syndrome (n = 3), and intestinal dysmotility (n = 3). None of these children had inflammatory disease or recent infection when studied. Fat-free mass (FFM), measured by body impedance analysis, fat mass (FM), measured by skinfold thickness, and energy intake were similar between the two groups, suggesting that CHPN had normal body composition and energy intake. Resting energy expenditure (REE), measured by indirect calorimetry, and TEE, assessed by a technique using 24-h heart-rate monitoring calibrated against indirect calorimetry and physical activity using a triaxial accelerometer, were simultaneously recorded and were also similar in the two groups. Sleeping energy expenditure (SEE), expressed per kilogram of FFM, was significantly greater in the CHPN group (median, 0.15; range, 0.10-0.23 kJ/min/kg FFM versus median, 0.12; range, 0.09-0.21 kJ/min/kg FFM for controls; p < 0.05, Wilcoxon rank test). These findings were explained by the high correlation between the energy flow infused by parenteral nutrition and sleeping energy expenditure (p < 0.05, Spearman test) and also-diet induced thermogenesis (p < 0.05 Spearman test). These results suggest that the energy requirements of children on long-term home parenteral nutrition programs do not differ from controls and that cyclic parenteral nutrition does not interfere with physical activity.

Further delineation of the congenital form of X-linked dyskeratosis congenita (Hoyeraal-Hreidarsson syndrome).

Hoyeraal-Hreidarsson syndrome represents a severe variant of dyskeratosis congenita (Zinsser-Cole-Engman syndrome). This X-linked recessive, progressive, multisystemic disorder reported so far in 12 pedigrees is characterised by intrauterine growth retardation, microcephaly, cerebellar hypoplasia, mental retardation, progressive combined immune deficiency and aplastic anaemia. Mutations in the DKC1gene on Xq28 have been identified in the X-linked form of dyskeratosis congenita and in some Hoyeraal-Hreidarsson syndrome patients. We report on two sibs and two other unrelated patients with the striking clinical features of Hoyeraal-Hreidarsson syndrome. Noticeably, all four had early digestive problems, with chronic, bloody diarrhoea and feeding problems causing one of the most difficult problems in the supportive treatment of this uniformly lethal condition. Pathological changes in the proliferative compartment of the digestive mucosa included alterations of the glandular architecture and focal rarefaction of the glands. This aspect seems consistent with altered telomerase function associated with a dyskerin mutation which may decrease the proliferative capacity of digestive epithelial cells. A missense mutation 146 C-->T (Thr49Met) in the DKC1gene was found in two unrelated patients, whereas mutation screening was negative for one single case. The absence of mutations of the DKC1gene in patients with Hoyeraal-Hreidarsson syndrome emphasises the probable implication of one or more other loci.