Human HOIP and LUBAC deficiency underlies autoinflammation, immunodeficiency, amylopectinosis, and lymphangiectasia

Boisson et al. report a human homozygous mutation of HOIP, the gene encoding the catalytic component of the linear ubiquitination chain assembly complex, LUBAC. The missense alleles impair the expression of HOIP, destabilizing the LUBAC complex and resulting in immune cell dysfunction leading to multiorgan inflammation, combined immunodeficiency, subclinical amylopectinosis, and systemic lymphangiectactasia.

Inherited, complete deficiency of human HOIL-1, a component of the linear ubiquitination chain assembly complex (LUBAC), underlies autoinflammation, infections, and amylopectinosis. We report the clinical description and molecular analysis of a novel inherited disorder of the human LUBAC complex. A patient with multiorgan autoinflammation, combined immunodeficiency, subclinical amylopectinosis, and systemic lymphangiectasia, is homozygous for a mutation in HOIP, the gene encoding the catalytic component of LUBAC. The missense allele (L72P, in the PUB domain) is at least severely hypomorphic, as it impairs HOIP expression and destabilizes the whole LUBAC complex. Linear ubiquitination and NF-κB activation are impaired in the patient’s fibroblasts stimulated by IL-1β or TNF. In contrast, the patient’s monocytes respond to IL-1β more vigorously than control monocytes. However, the activation and differentiation of the patient’s B cells are impaired in response to CD40 engagement. These cellular and clinical phenotypes largely overlap those of HOIL-1-deficient patients. Clinical differences between HOIL-1- and HOIP-mutated patients may result from differences between the mutations, the loci, or other factors. Our findings show that human HOIP is essential for the assembly and function of LUBAC and for various processes governing inflammation and immunity in both hematopoietic and nonhematopoietic cells.

Aryl hydrocarbon receptor-dependent induction of liver fibrosis by dioxin

The contribution of environmental pollutants to liver fibrosis is an important and poorly explored issue. In vitro studies suggest that the environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other aryl hydrocarbon receptor (AhR) ligands induce several genes that are known to be upregulated during liver fibrosis. Our aim was to determine whether exposure to such pollutants can lead to liver fibrosis and to characterize the mechanisms of action. Mice were treated for 2, 14, or 42 days, once a week with 25 µg/kg of TCDD. Gene and protein expression, in vitro and in vivo, as well as liver histology were investigated for each treatment. Treatment of mice with TCDD for 2 weeks modified the hepatic expression of markers of fibrosis such as collagen 1A1 and α-smooth muscle actin. This is not observed in AhR knockout mice. Following 6 weeks of treatment, histological features of murine hepatic fibrosis became apparent. In parallel, the levels of inflammatory cytokines (interleukin-1 beta, tumor necrosis factor α) and of markers of activated fibroblasts(fibroblast-specific protein 1) were found to be upregulated. Interestingly, we also found increased expression of genes of the TGF-β pathway and a concomitant decrease of miR-200a levels. Because the transcription factors of the Snail family were shown to be involved in liver fibrosis, we studied their regulation by TCDD. Two members of the Snail family were increased, whereas their negative targets, the epithelial marker E-cadherin and Claudin 1, were decreased. Further, the expression of mesenchymal markers was increased. Finally, we confirmed that Snai2 is a direct transcriptional target of TCDD in the human hepatocarcinoma cell line, HepG2. The AhR ligand, TCDD, induces hepatic fibrosis by directly regulating profibrotic pathways.

FGF10 Signaling differences between type I pleuropulmonary blastoma and congenital cystic adenomatoid malformation

Background

Type I pleuropulmonary blastoma (PPB) and congenital cystic adenomatoid malformation of the lung (CCAM) are cystic lung diseases of childhood. Their clinical and radiological presentations are often similar, and pathologic discrimination remains difficult in many cases. As a consequence, type I PPB and CCAM are frequently confused, leading to delayed adequate management for type I PPB. Recent studies have suggested a role for fibroblast growth factor (FGF) 10 signal pathway in CCAM pathogenesis. The objective of our study was to determine whether FGF10 signaling differs between CCAM and type I PPB.

Methods

Immunohistochemical studies were performed for expression of FGF10, its receptor FGFR2b, and its inhibitor sonic hedgehog (SHH) in focal type I PPB (n=6), CCAM type I (n=7), CCAM type II (n=7), and control lungs (n=5).

Results

FGF10, FGFR2b, and SHH expressions differed markedly between type I PPB and both types of CCAM. Type I and type II CCAM cystic walls expressed FGF10, FGFR2b, and SHH, whereas staining was absent or poor in type I PBB cystic walls. Expression of FGF10, FGFR2b, and SHH did not differ between CCAM cystic walls and control airway walls.

Conclusions

These findings show that immunohistochemistry with FGF10, FGFR2b, or SHH could be useful in differentiating CCAM from type I PPB, when a child presents with a focal cystic lung lesion. The absence of strong expression of FGF10, FGFR2b, and/or SHH makes the diagnosis of CCAM very doubtful.

Mutations in PDGFRB cause autosomal-dominant infantile myofibromatosis

Infantile myofibromatosis (IM) is a disorder of mesenchymal proliferation characterized by the development of nonmetastasizing tumors in the skin, muscle, bone, and viscera. Occurrence within families across multiple generations is suggestive of an autosomal-dominant (AD) inheritance pattern, but autosomal-recessive (AR) modes of inheritance have also been proposed. We performed whole-exome sequencing (WES) in members of nine unrelated families clinically diagnosed with AD IM to identify the genetic origin of the disorder. In eight of the families, we identified one of two disease-causing mutations, c.1978C>A (p.Pro660Thr) and c.1681C>T (p.Arg561Cys), in PDGFRB. Intriguingly, one family did not have either of these PDGFRB mutations but all affected individuals had a c.4556T>C (p.Leu1519Pro) mutation in NOTCH3. Our studies suggest that mutations in PDGFRB are a cause of IM and highlight NOTCH3 as a candidate gene. Further studies of the crosstalk between PDGFRB and NOTCH pathways may offer new opportunities to identify mutations in other genes that result in IM and is a necessary first step toward understanding the mechanisms of both tumor growth and regression and its targeted treatment.

Immunodeficiency, autoinflammation and amylopectinosis in humans with inherited HOIL-1 and LUBAC deficiency

We report the clinical description and molecular dissection of a new fatal human inherited disorder characterized by chronic auto-inflammation, invasive bacterial infections and muscular amylopectinosis. Patients from two kindreds carried biallelic loss-of-expression and loss-of-function mutations in HOIL1, a component the linear ubiquitination chain assembly complex (LUBAC). These mutations resulted in impairment of LUBAC stability. NF-κB activation in response to interleukin-1β (IL-1β) was compromised in the patients’ fibroblasts. By contrast, the patients’ mononuclear leukocytes, particularly monocytes, were hyperresponsive to IL-1β. The consequences of human HOIL-1 and LUBAC deficiencies for IL-1β responses thus differed between cell types, consistent with the unique association of auto-inflammation and immunodeficiency in these patients. These data suggest that LUBAC regulates NF-κB-dependent IL-1β responses differently in different cell types.

Pediatric ulcerative colitis associated with autoimmune diseases: a distinct form of inflammatory bowel disease?

BACKGROUND

The pathogenesis of inflammatory bowel disease (IBD) is multifactorial, with some patients presenting additional autoimmune symptoms. Inflammatory colitis associated with autoimmune (AI) liver disease appears to have clinical features different from those of "classical" ulcerative colitis (CUC). The aim of this study was to describe these features, in order to differentiate a subgroup of colitis associated with autoimmunity (CAI) from CUC.

METHODS

Twenty-eight consecutive children with inflammatory colitis associated with primary sclerosing cholangitis (PSC), celiac disease, or AI hepatitis were compared with a matched control group of 27 children with isolated UC. Clinical course, histology, as well as inflammatory profile in the colonic mucosa based on real-time polymerase chain reaction (PCR) were analyzed.

RESULTS

In CAI the main digestive symptoms at disease onset were abdominal pain (12/28) and bloody strings in the stool (12/28), along with a high prevalence of autoimmune diseases in relatives, as compared with bloody diarrhea in the CUC group (26/27). At diagnosis, pancolitis was seen in 18/28 CAI patients compared with 8/27 in UC. In CAI, the pathological findings were different from CUC: 1) major lesions predominantly located in the right colon; 2) pseudo-villous appearance of the mucosa, and strong infiltration with eosinophils; 3) mild glandular lesions; and 4) differing inflammatory infiltrate with reduced FOXP3, interleukin (IL)-2, and thymic stromal lymphopoietin (TSLP) levels. Evolution in CAI was less aggressive, requiring less corticosteroids/immunomodulators.

CONCLUSIONS

Precise clinical, histological, and molecular analyses reveal marked differences between patients with CUC and those with associated AI phenomena, supporting the hypothesis of a distinct AI presentation of IBD.

Secondary pulmonary alveolar proteinosis after unrelated cord blood hematopoietic cell transplantation

PAP is a rare alveolointerstitial lung disorder characterized histologically by the intra-alveolar accumulation of eosinophilic and PAS-positive material. We observed two cases of PAP after unrelated CB hematopoietic progenitor cell transplantation in children with ALL. No antagonist activity toward GM-CSF was identified in the patient tested. The putative multifactorial PAP etiology is discussed. This potentially curable condition should be considered in a CB allograft recipient with alveolointerstial lung disorder.

A t(17;22)(q21;q12) with partial ETV4 deletion in a soft tissue Ewing sarcoma

Cytogenetic analysis of a lumbar soft tissue Ewing sarcoma (ES) in a 7-month-old female child showed a t(17;22)(q21;q12), a rare translocation leading to an EWSR1-ETV4 chimeric transcript. These findings were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH) techniques. The breakpoints were characterized by direct sequencing of the chimeric fusion gene. Tumor genotyping using the Affymetrix Genome-Wide Human single nucleotide polymorphism (SNP) array 6.0 Genechip identified deletions of both chromosomal regions involved in the translocation, resulting in partial deletion of ETV4, but an uninvolved EWSR1 gene. The creation of a fusion between EWSR1 and an ETS family gene consecutive to a chromosomal translocation is characteristic of the Ewing family of tumors (EFT). This is the first report of a deletion involving the two breakpoints in an EWS-ETS translocation. To date, only two cases of t(17;22)(q21;q12) in Ewing sarcoma have been reported, with no associated deletion. Interestingly, both cases had also occurred in soft tissue tumors, which are less common than their bone-involving counterparts.

Congenital hyperinsulinism: current trends in diagnosis and therapy

Congenital hyperinsulinism (HI) is an inappropriate insulin secretion by the pancreatic β-cells secondary to various genetic disorders. The incidence is estimated at 1/50, 000 live births, but it may be as high as 1/2, 500 in countries with substantial consanguinity. Recurrent episodes of hyperinsulinemic hypoglycemia may expose to high risk of brain damage. Hypoglycemias are diagnosed because of seizures, a faint, or any other neurological symptom, in the neonatal period or later, usually within the first two years of life. After the neonatal period, the patient can present the typical clinical features of a hypoglycemia: pallor, sweat and tachycardia. HI is a heterogeneous disorder with two main clinically indistinguishable histopathological lesions: diffuse and focal. Atypical lesions are under characterization. Recessive ABCC8 mutations (encoding SUR1, subunit of a potassium channel) and, more rarely, recessive KCNJ11 (encoding Kir6.2, subunit of the same potassium channel) mutations, are responsible for most severe diazoxide-unresponsive HI. Focal HI, also diazoxide-unresponsive, is due to the combination of a paternally-inherited ABCC8 or KCNJ11 mutation and a paternal isodisomy of the 11p15 region, which is specific to the islets cells within the focal lesion. Genetics and ¹⁸F-fluoro-L-DOPA positron emission tomography (PET) help to diagnose diffuse or focal forms of HI. Hypoglycemias must be rapidly and intensively treated to prevent severe and irreversible brain damage. This includes a glucose load and/or a glucagon injection, at the time of hypoglycemia, to correct it. Then a treatment to prevent the recurrence of hypoglycemia must be set, which may include frequent and glucose-enriched feeding, diazoxide and octreotide. When medical and dietary therapies are ineffective, or when a focal HI is suspected, surgical treatment is required. Focal HI may be definitively cured when the partial pancreatectomy removes the whole lesion. By contrast, the long-term outcome of diffuse HI after subtotal pancreatectomy is characterized by a high risk of diabetes, but the time of its onset is hardly predictable.

Foxl-2 in gonad development and pathology

The Foxl-2 gene is involved in eyelid and ovary development. Mutations can lead to a shortened protein and malformations such as BPES associated or not to POF. Forkhead point mutation C134W is a marker of adult type granulosa cell tumors only. Foxl-2 dysregulation is also present in DSD and DSD associated tumors such as Gonadoblastoma and gonadoblastoma like intratubular undetermined germ cell neoplasia. A similar spectrum of pathology involvement is also found for WT1 and RET and gives a new insight into the relationship between development, malformations and oncogenesis.

Coexistence of a choriocarcinoma and a gonadoblastoma in the gonad of a 46,XY female: a single nucleotide polymorphism array analysis

Females with 46,XY complete gonadal dysgenesis are at significant risk of developing germ cell tumors, mostly gonadoblastomas. We present here the case of 2 half-sisters, sharing the same father, diagnosed with 46,XY complete gonadal dysgenesis. The 1st sister developed a gonadoblastoma and an invasive dysgerminoma, whereas the 2nd sister developed a gonadoblastoma and an invasive choriocarcinoma within the same gonad. No SRY mutation, chromosome abnormalities, or mosaicism were detected in blood. Single nucleotide polymorphism (SNP) profiling of the choriocarcinoma revealed a complex hyperdiploid pattern with gains of 1 to 4 copies of material from several autosomes, as well as the loss of the Y chromosome and a homozygous SNP profile without copy number change for the X chromosome. Our results are in agreement with the recurrent chromosome gains and losses previously published in germ cell tumors, and the coexistence of both tumors within the same gonad suggests that choriocarcinomas may derive from gonadoblastomas.

Beta-catenin mutation does not seem to have an effect on the tumorigenesis of pediatric rhabdomyosarcomas

Involvement of the Wnt signal transduction pathway has been shown in different pediatric embryonal tumors, such as hepatoblastoma, nephroblastoma, pancreatoblastoma, and medulloblastoma. There are few data available on the status of beta-catenin in rhabdomyosarcoma (RMS), another pediatric embryonal tumor. The aims of this study were 1st to verify the status of the exon 3 of CTNNB1 and 2nd to assess the usefulness of beta-catenin immunostaining in a small series of 8 embryonal RMS, 3 alveolar RMS, and 1 sclerosing RMS (SRMS). Sequence analysis revealed no mutations in the exon 3 of CTNNB1 in all the tumors studied. All RMS showed a cytoplasmic beta-catenin staining with cytoplasmic membrane reinforcement and no nuclear delocalization. We conclude that there is no evidence of beta-catenin mutation in the genesis of rhabdomyosarcoma and that beta-catenin does not represent a useful immunomarker to help distinguish between embryonal RMS and alveolar RMS.

Fatal cases of Staphylococcus aureus pleural empyema in infants

Community-associated infections and especially pleural empyema due to Staphylococcus aureus are increasing worldwide. The virulence of staphylococcal strains is notably determined by different toxin expressing-genes, such as the Panton-Valentine leukocidin (PVL) gene found in S. aureus isolates obtained from pediatric necrotizing pneumonia samples. We describe 2 similar cases of infants with severe respiratory distress and death after an upper respiratory tract infection, having occurred in the same urban area during the same winter time. Necropsies performed between November 2006 and March 2007 revealed bronchopneumonia and an important pleural empyema, justifying the review of clinical charts and laboratory exams. A methicillin-sensitive S. aureus (MSSA) isolate carrying the PVL gene was identified in both cases. We have subsequently cared for an additional case in the same time interval with sudden death and similar pathological findings. No positive microbiological results were obtained, a negative finding possibly related to a 5-day antibiotics regimen. This report describes the pathological features of these cases and stresses the need to recognize PVL-positive S. aureus infections in young children. Finally, we believe that all lethal infections due to PVL-positive S. aureus, independently of the methicillin resistance profile, deserve a mandatory report to the provincial public health authorities.

Lethal respiratory failure and mild primary hypothyroidism in a term girl with a de novo heterozygous mutation in the TITF1/NKX2.1 gene

CONTEXT

Thyroid transcription factor 1 (TITF1/NKX2.1) is expressed in the thyroid, lung, ventral forebrain, and pituitary. In the lung, TITF1/NKX2.1 activates the expression of genes critical for lung development and function. Titf/Nkx2.1(-/-) mice have pituitary and thyroid aplasia but also impairment of pulmonary branching. Humans with heterozygous TITF1/NKX2.1 mutations present with various combinations of primary hypothyroidism, respiratory distress, and neurological disorders.

OBJECTIVE

The objective of the study was to report clinical and molecular studies of the first patient with lethal neonatal respiratory distress from a novel heterozygous TITF1/NKX2.1 mutation.

PARTICIPANT

This girl, the first child of healthy nonconsanguineous French-Canadian parents, was born at 41 wk. Birth weight was 3,460 g and Apgar scores were normal. Soon after birth, she developed acute respiratory failure with pulmonary hypertension. At neonatal screening on the second day of life, TSH was 31 mU/liter (N <15) and total T(4) 245 nmol/liter (N = 120-350). Despite mechanical ventilation, thyroxine, surfactant, and pulmonary vasodilators, the patient died on the 40th day.

RESULTS

Histopathology revealed pulmonary tissue with low alveolar counts. The thyroid was normal. Sequencing of the patient's lymphocyte DNA revealed a novel heterozygous TITF1/NKX2.1 mutation (I207F). This mutation was not found in either parent. In vitro, the mutant TITF-1 had reduced DNA binding and transactivation capacity.

CONCLUSION

This is the first reported case of a heterozygous TITF1/NKX2.1 mutation leading to neonatal death from respiratory failure. The association of severe unexplained respiratory distress in a term neonate with mild primary hypothyroidism is the clue that led to the diagnosis.

An immunohistochemical evaluation of C4d deposition in pediatric inflammatory liver diseases

C4d is a marker of the activated complement cascade used to assess the humoral component of rejection, mostly in kidney allograft transplants. The role of C4d deposition has recently been addressed in hepatic allograft but has never been tested in a series of inflammatory liver diseases without previous liver transplantation. The aim of this study was to compare the immunohistochemistry profile of C4d deposition in a pediatric population, between a cohort of patients with autoimmune hepatitis (AIH) and a series of patients with chronic viral hepatitis B or C. Immunohistochemical analysis was performed on 64 liver biopsies. C4d deposition was observed in 25 (83%) of 30 AIH biopsies examined, in 6 (40%) of 15 hepatitis C biopsies, and in 17 (89%) of 19 hepatitis B biopsies. No expression of C4d was observed in 4 noninflammatory liver specimens used as negative controls. In the AIH group, a staining of the periportal sinusoids was often observed, as well as focal periductal reinforcement. Centrolobular vein staining was observed in the 3 hepatitis groups with a higher frequency in viral hepatitis B biopsies. Regardless of the etiology, lymphoid aggregates demonstrated an accentuation of the staining. These results confirm a role for a humoral immune response in pediatric autoimmune as well as in viral hepatitis. The relative ratios of positive cases imply that this immunostaining does not represent a strong diagnostic criterion in the differentiation between viral hepatitis and AIH. However, differences in the pattern of the staining were observed, depending on the etiology of the disease. The high prevalence of C4d reactivity in viral hepatitis strongly suggests that C4d does not represent a useful marker in the differentiation between acute rejection and viral hepatitis relapse in liver transplants.

Interface hepatitis is associated with a high incidence of late graft fibrosis in a group of tightly monitored pediatric orthotopic liver transplantation patients

Chronic graft dysfunction, manifesting with elevated liver enzymes and histological features of interface hepatitis (IH), is being increasingly recognized as a long-term problem after liver transplantation. The aim of this study was to characterize our group of post-orthotopic liver transplantation (OLT) patients with respect to clinical, laboratory, and histological signs of IH. A retrospective study of charts and liver biopsy specimens from patients transplanted between 1986 and 1999 was used. Histological features of IH were found in 29/119 patients at a median interval of 23.9 months (95% confidence interval -28.2 to 52.6) after OLT. All patients with IH had risk factors for chronic rejection, such as steroid-resistant rejection, acute rejection later than 3 months post-OLT, female receiver of male graft, or pretransplant cytomegalovirus (CMV)-positive serology with a CMV-negative donor liver. None of the 29 had features favoring a diagnosis of de novo autoimmune hepatitis, but 4 had isolated hypergammaglobulinemia, and 4 had non-organ-specific autoantibodies without hyperimmunoglobulin G. Sixteen of 29 patients also had features of chronic rejection, such as foam cell arteriopathy, loss of bile ducts, or pericentral fibrosis. After abnormal biopsy, all but 1 patient were switched to tacrolimus. During a median follow-up of 12 years, death occurred in 5, retransplantation occurred in 7, and definite cirrhosis occurred in 4. In conclusion, IH was detected in 24.4% of our patients and was associated with a high degree of fibrosis development. Most likely, IH represents a form of chronic rejection directed against periportal hepatocytes.

Caudal dysgenesis, sirenomelia, and situs inversus totalis: a primitive defect in blastogenesis

Caudal dysgenesis (CD) constitutes a heterogeneous spectrum of congenital caudal anomalies, including varying degrees of agenesis of the vertebral column, as well as anorectal and genitourinary anomalies. Sirenomelia, characterized by a fusion of the lower limbs, could represent the most severe end of this spectrum. The two main debated pathogenic hypotheses are an aberrant vascular supply versus a primary axial mesoderm defect. We present the autopsy findings of two fetuses of non-diabetic mothers, with normal karyotype. Both fetuses presented situs inversus associated with a CD, in one case consisting of sirenomelia, establishing a very rare association profile that might be random. This association also suggests the occurrence of a common pathogenic mechanism, in accordance to recent genetic data, such as displayed in the Kif3A murine mutation phenotype. Some cases of sirenomelia and CD could represent developmental field defects of blastogenesis involving the caudal mesoderm, rather than being related to vascular insufficiency.

Accessory liver lobe with mesothelial inclusion cysts in an omphalocele: a new malformative association

Mesothelial inclusion cysts represent benign lesions that have been reported in a wide variety of locations. Peritoneal cysts are observed and visceral involvement has been described, notably of intraperitoneal organs such as the spleen and the testis. We report the cases of 2 neonates who underwent surgical management of an omphalocele. The hernial sac contained an accessory liver lobe, displaying in both cases multilocular mesothelial inclusion cysts. The hobnail cells lining the cysts exhibited calretinin and cytokeratin immunohistochemical reactivity, as well as focal D2-40 reactivity. One of the cases occurred in the setting of a Beckwith-Wiedemann syndrome (MIM 130650), an overgrowth disorder notably associated with omphalocele and hepatic anomalies and tumors. However, no hepatic mesothelial cyst has been described in this syndrome. In the 2nd case the omphalocele and the hepatic cysts were the sole lesions observed in the neonate. To the best of our knowledge, these 2 cases represent the first description of such an association.

Familial association of pleuropulmonary blastoma with cystic nephroma and other renal tumors: a report from the International Pleuropulmonary Blastoma Registry

OBJECTIVE

To characterize the association of pleuropulmonary blastoma (PPB) with cystic nephroma (CN) and other renal tumors.

STUDY DESIGN

Complete clinicopathologic review of cases from the International PPB Registry and literature.

RESULTS

We identified 18 patients with PPB associated with 20 renal tumors (15 CN), either in themselves or family members. All patients with PPB were <5 years of age. All but one of the renal diagnoses were made before 4 years of age. Eleven children had both PPB and renal tumor, one of whom also had a sibling with CN. Six children with PPB alone had one or more family members with CN. The mother of one child with PPB had Wilms' tumor. Pulmonary disease was bilateral in four patients. Renal disease was bilateral in three patients. Two children with PPB and bilateral renal cystic tumors also had intussusceptions because of small bowel juvenile polyps. In six families, dysplasia/neoplasia affected organs other than lung and kidney.

CONCLUSIONS

CN or related tumors were found in 9.2% of 152 Registry-reviewed PPB cases. The occurrence of rare pulmonary and renal tumors together in patients and/or family members, the early age of onset, and the multiplicity of tumors is compatible with a constitutional genetic predisposition.

A complex translocation (6;12;8)(q25;q24.3;q13) in a fibrous hamartoma of infancy

We report the case of an 18-month-old girl who came to medical attention with a left cervical mass. Surgical excision was performed 16 months later. Histology revealed a fibrous hamartoma of infancy. Follow-up has been uneventful, and no recurrence of the mass has been observed. Cytogenetic analysis showed a complex translocation involving chromosomes 6, 8, and 12, namely, t(6;12;8)(q25;q24.3;q13). This case represents the second cytogenetic analysis reported to date in fibrous hamartoma of infancy and reveals a different translocation than the reciprocal translocation t(2;3)(q31;q21) previously reported.

Obstetric US: watch the fetal hands

Hand anomalies are difficult to diagnose and are often overlooked during prenatal ultrasonography (US). The spectrum of malformations varies from subtle finger deformities to the complete amputation of limbs. Malformations of the hand can be classified, according to the predominant anomaly, among the following categories: alignment abnormalities (clenched hand, camptodactyly, clinodactyly, hypokinesia, clubhand, phocomelia), thumb anomalies, abnormal size (macrodactyly, trident hand), abnormal echogenicity (abnormal calcifications), abnormal number (polydactyly, syndactyly, ectrodactyly), and constriction band sequence. A fetal hand anomaly has important diagnostic and prognostic implications as well as functional consequences. Malformation may be isolated but often is associated with a syndrome or karyotype anomaly. Classification and characterization of the anomaly help to narrow the differential diagnosis: Some malformations (clenched hand, hitchhiker thumb) are highly suggestive of a specific diagnosis. The detection of a fetal hand malformation warrants a complete work-up, including complete fetal and cardiac US examinations, as well as genetic counseling to determine whether familial inquiry and karyotype analysis are necessary.

Bilateral cystic dysplasia of the rete testis with renal adysplasia

Cystic dyplasia of the rete testis (CDRT) is an uncommon, generally unilateral lesion characterized by anastomosing cystic spaces lined by a flattened simple cuboidal epithelium in the rete testis. In the literature this lesion often is associated with an ipsilateral urogenital lesion such as renal agenesia or multicystic dysplasia of the kidney, in order of frequency. The pathogenesis is explained by some authors by their common embryologic origin. We are reporting the finding of bilateral CDRT associated with ultrasound-diagnosed renal adysplasia in a 20-week gestational age fetus with oligohydramnios. Although CDRT has been referred to as being associated with multicystic renal dysplasia or renal agenesis, the present case appears to be unique in combining all the malformations together.

An association of pleuropulmonary blastoma and cystic nephroma: possible genetic association

The association of pleuropulmonary blastoma and cystic nephroma is an uncommon entity, with only 4 cases of such an association in the same patient described in English literature. We report a 5th histologically documented case in a 32-month-old boy. The boy underwent a pulmonary biopsy that showed a pleuropulmonary blastoma and a nephrectomy that showed a cystic nephroma. The pleuropulmonary mass showed an important regression with postbiopsy chemotherapy, allowing subsequent tumorectomy. To date very little is known about this rare entity, and a genetic link between these 2 tumors is hypothesized.

Male pseudohermaphroditism and gonadal mosaicism in a 47,XY,+22 fetus

Trisomy 22 syndrome manifestations include cranial and facial anomalies. Ambiguous genitalia have been described in some fetus, but histological examination of the gonads has been rarely provided. We report here the first case of a male pseudohermaphrodite fetus with non-mosaic full trisomy 22 in amniocytes and presenting with ambiguous external genitalia, testes, and a uterus. In this case, we have further analyzed cytogenetically gonadal and uterine tissues. FISH analyses on paraffin-embedded gonads and uterus indicated the presence of two cell lines: XY and monosomy X, with 22%-50% of uterine cells having monosomy X, while 85%-100% of right and 77%-96% of left testicular cells were XY. The distribution of sex chromosomes observed in these tissues could explain the sexual differentiation observed in this fetus. On the other hand, this phenotype could also have resulted from cryptic anomalies in one or several genes implicated in sexual differentiation. Further evidence is thus needed before identifying the true cause of pseudohermaphroditism in our patient.

Eosinophilic esophagitis in children: symptoms, histology and pH probe results

AIM

To review the authors' experience with eosinophilic esophagitis.

METHODS

Between 1993 and 2001, the authors identified 12 patients with eosinophilic esophagitis defined on histologic criteria (> or = 20 eosinophils per high-power field in the distal esophageal epithelium). The authors reviewed medical records for details of clinical presentation; laboratory data; radiologic, endoscopic, and histologic findings; and the results of continuous esophageal pH probe monitoring.

RESULTS

Seventy-five percent of the patients were male. The median age at presentation was 10.8 years (range, 1-17 years). Commonly reported symptoms were dysphagia with solid food (66%), epigastric pain (42%), food impaction (50%), and vomiting (8%). Food allergy was reported in 50% and asthma in 33%. Peripheral eosinophilia (> 700/mm3) was found in 42%. Upper gastrointestinal series performed in eight patients, showed esophageal luminal narrowing in three. Computed tomography, performed in two patients, revealed thickening of the esophageal wall. Esophageal pH probe monitoring, performed in nine patients, revealed no abnormal acid reflux. All of the monitored patients had episodic alkalinization of the esophagus. Upper endoscopic analysis revealed white specks on the esophageal mucosa in 42%, esophageal narrowing in 33%, esophageal rings in 25%, and esophageal furrowing in 8%. The mean eosinophils per high-power field was 65 (range, 20-200). Histologic characteristics included juxtaluminar (33%) and peripapillary clusters of eosinophils (33%), increased papillary height (50%), and basal cell hyperplasia (34%).

CONCLUSION

Solid food dysphagia was the most common feature of eosinophilic esophagitis in our patients. Alkalinization of the esophagus was found in all nine pH probe recordings of eosinophilic esophagitis patients and may represent a previously unreported characteristic of the condition.

Genetics of congenital hyperinsulinism

Congenital hyperinsulinism (CHI) is a clinically and genetically heterogeneous entity and causes severe hypoglycemia in neonates and infants. The clinical heterogeneity is manifested by severity ranging from extremely severe, life-threatening disease to very mild clinical symptoms, which may even be difficult to identify. Furthermore, clinical responsiveness to medical and surgical management is extremely variable. Recent discoveries have begun to clarify the molecular etiology of this disease in about 50% of cases. Mutations in five different genes have been identified in patients with this clinical syndrome. Most cases are caused by mutations in the genes ABCC8 and KCNJ11 coding for either of the two subunits of the beta-cell KATP channel (SUR1 and Kir6.2). Recessive mutations of the beta-cell K(ATP) channel genes cause diffuse HI, whereas loss of heterozygosity together with inheritance of a paternal mutation causes focal adenomatous HI. In other cases, CHI is caused by mutations in genes coding for the beta-cell enzymes glucokinase (GK), glutamate dehydrogenase (GDH), and SCHAD. However, for as many as 50% of the cases, no genetic etiology has yet been determined. The study of the genetics of this disease has provided important new information regarding beta-cell physiology.

Genetic control of myeloproliferation in BXH-2 mice

While studying the unique Nramp1 (Slc11a1)-independent susceptibility to Mycobacterium bovis (BCG) infection of BXH-2 mice, we noted that these mice develop important splenomegaly and enlargement of lymph nodes. Segregation analyses in several F2 crosses showed that splenomegaly segregates as a single recessive trait caused by a novel mutation in BXH-2, independent of the infection. Histologic and fluorescence-activated cell sorter (FACS) analyses indicated that splenomegaly is associated with a large increase in Mac1+/GR1+ (macrophage antigen-1+/granulocyte differentiation antigen 1+) granulocyte precursors in spleen, lymph nodes, and bone marrow, resembling a myeloproliferative syndrome. This is concomitant to extramedullary erythropoiesis in the spleen, as measured by proportion of Ter119+ erythroid cells. The locus controlling this myeloproliferative syndrome and splenomegaly was designated Myls and maps to an 18 centimorgan (cM) region of chromosome 8, which also contains an integrated copy of an N-ecotropic murine leukemia virus (MuLV) provirus (Emv2). The relationship between Myls, expansion of Mac1+/GR1+ cells, and Emv2 was investigated. Homozygosity at Myls is necessary but not sufficient for B-ecotropic virus replication in splenocytes, the extent of which appears to be under separate genetic control. Our results suggest a model in which Myls-dependent myeloproliferation in BXH-2 acts as a predisposing factor for the subsequent development of virally induced myeloid leukemia characteristic of this strain.

The genetics of neonatal hyperinsulinism

Congenital hyperinsulinism (CHI) is the most important cause of persistent hypoglycaemia in the neonate and infant. It is a clinically and genetically heterogeneous entity. The clinical heterogeneity is manifested by severity ranging from extremely severe life-threatening disease to very mild clinical symptoms which may even be difficult to identify. Furthermore, clinical responsiveness to medical and surgical management is extremely variable. Two histopathological forms have been described: a diffuse form of CHI and a focal form of CHI. Recent discoveries have begun to clarify the molecular aetiology of the disease and therefore the mechanisms responsible for its clinical heterogeneity are becoming clearer. Mutations in four different genes have been identified in patients with CHI. Most cases are caused by mutations in genes coding for either of the two subunits of the beta-cell K(ATP) channel (ABCC8 and KCNJ11). In the diffuse form of CHI, the hyperinsulinism is due to a recessive mutation of both alleles of these genes (rare dominant mutations have been described). In the focal form of CHI, two events intervene: first, the inheritance of a paternal ABCC8/KCNJ11 mutation; second, the focal reduction to homozygosity of the mutation during pancreatic development by a localized loss of the maternal 11p15 region. Others cases of CHI are due to rare mutations in the beta-cell enzymes glucokinase (only one family described) and glutamate dehydrogenase in hyperammonaemia-associated hyperinsulinism. However, in as many as 50% of cases, no genetic aetiology has yet been identified.

A novel CLTC-TFE3 gene fusion in pediatric renal adenocarcinoma with t(X;17)(p11.2;q23)

A distinctive subset of renal carcinomas is associated with Xp11. 2 translocations and resulting TFE3 gene fusions (PRCC-TFE3, PSF-TFE3, NONO-TFE3, ASPL-TFE3), encoding related aberrant transcription factors. We report the cloning of a novel clathrin heavy-chain gene (CLTC)-TFE3 gene fusion resulting from a t(X;17)(p11.2;q23) in a renal carcinoma arising in a 14-year-old boy. The fusion transcript joined the 5' exons of CLTC on chromosome band 17q23 to the 3' exons of TFE3. CLTC encodes a major subunit of clathrin, a multimeric protein on cytoplasmic organelles, and is a known recurrent fusion partner of the ALK tyrosine kinase gene in anaplastic large-cell lymphoma and inflammatory myofibroblastic tumors. The predicted CLTC-TFE3 product retains the nuclear localization and DNA-binding domains of TFE3, but lacks the multimerization domain of CLTC. The present renal tumor demonstrated morphologic and immunohistochemical features of both PRCC-TFE3 and ASPL-TFE3 carcinomas, including strong nuclear immunoreactivity for the TFE3 C-terminal and only minimal expression of epithelial proteins. However, unlike most renal carcinomas, it also focally expressed melanocytic proteins. The present report highlights the promiscuity of certain genes involved in chromosomal translocations. Further analysis of the shared features of CLTC and other TFE3 fusion partners may shed light on the essential biology of TFE3 fusion proteins.

Five new cases of juvenile renal cell carcinoma with translocations involving Xp11.2: a cytogenetic and morphologic study

Two cases of renal cell carcinoma (RCC) carrying a t(X;1)(p11.2;q21) in a 12-year-old boy and a 14 year-old girl, two cases with a t(X;1)(p11.2;p34) in a 9-year-old boy and a 31-year-old woman, and one case with a t(X;17)(p11.2;q25) in a 15-year-old boy are reported. Two are likely papillary RCC, with clear or slightly eosinophilic cells, and two to a clear cell RCC; one shows a mixture of papillary and clear cell RCC architecture. Renal cell carcinomas with translocations involving Xp11.2 form a specific entity characterized by subtle pathologic features and younger age of occurrence, especially for those with the t(X;17).

The focal form of persistent hyperinsulinemic hypoglycemia of infancy: morphological and molecular studies show structural and functional differences with insulinoma

Paternal mutation of ATP-sensitive K(+) (K(ATP)) channel genes and loss of heterozygosity (LOH) of the 11p15 region including the maternal alleles of ABCC8, IGF2, and CDKN1C characterize the focal form of persistent hyperinsulinemic hypoglycemia of infancy (FoPHHI). We aimed to understand the actual nature of FoPHHI in comparison with insulinoma. In FoPHHI, the lesion consists in clusters of beta-cells surrounded by non-beta-cells. Compared with adjacent islets, proinsulin mRNA is similar and proinsulin production higher (P < or = 0.02), indicating regulation at a translational level, with slightly lower insulin stock and lower ABCC8 peptide labeling (P<0.05). Insulinomas, composed of beta-cell nests or cords, have similar proinsulin mRNA compared with adjacent islets, highly variable proinsulin production, lower insulin stock (P < or = 0.02), and higher ABCC8 peptide labeling (P<0.05). Proinsulin mRNA is lower than in FoPHHI (P<0.001). Islets adjacent to FoPHHI appear to be resting, in contrast to those adjacent to insulinomas, evidencing intrapancreatic regulation of islet beta-cell activity. IGF2 peptide is present inside and outside both lesions, but IGF2 mRNA is restricted to the lesions. The 11p15 LOH and absence of CDKN1C peptide staining are demonstrated in all FoPHHI but also in three of eight insulinomas. Despite some molecular similarities, FoPHHI is thus fundamentally different from insulinoma.

Cadherins in Wilms' tumor: E-cadherin expression despite absence of WT1

Loss of heterozygosity of chromosome 16q occurs in 17-25% of Wilms' tumors. Two cadherin genes mapping to 16q22 were chosen as candidate gens: E-CAD, encoding epithelial cadherin, because it is involved in kidney development and it was recently reported to be a WT1 target; and KSP-CAD because it encodes a kidney-specific cadherin. By RT-PCR analysis in a series of 39 Wilms' tumors, we identified a very low expression of E-CAD and KSP-CAD in 72% and 95% of the tumors, respectively. To ascertain whether down-expression of these genes could be related to WT1 alterations in tumors, we looked for a relationship between WT1 and CAD expression. Our data suggest (i) the existence of alternative mechanisms for regulating E-CAD expression, and (ii) that E-CAD does not belong to the WT1 pathway that is altered in Wilms' tumorigenesis.

PRCC-TFE3 renal carcinomas: morphologic, immunohistochemical, ultrastructural, and molecular analysis of an entity associated with the t(X;1)(p11.2;q21)

The reappraisal of genetically defined subsets of renal tumors can help to highlight the key pathologic features of specific neoplastic entities. We report the morphologic, immunophenotypic, ultrastructural, and molecular features of 11 renal carcinomas bearing a t(X;1)(p11.2;q21) and/or the resulting PRCC-TFE3 gene fusion. The male/female ratio was 4:7. Ten patients were in the age range of 9-29 years and one was 64 years old (mean 21.3 years, median 15 years). The predominant histologic pattern was nested, with islands of tumor cells compartmentalized by thin-walled capillary vasculature. Minor variations on this pattern yielded solid, acinar, alveolar, and tubular architecture. Papillary architecture was seen in nine cases, usually as a minor component. Neoplastic cells were typically characterized by irregularly shaped nuclei with vesicular chromatin and small nucleoli not visible with a 10x objective, and cytoplasm that ranged from clear to densely granular and eosinophilic. Mitoses were extremely rare; 5 were found in 900 high power fields examined from the 11 neoplasms. The most distinctive immunohistochemical feature of these neoplasms was moderate to intense nuclear labeling for TFE3 protein. These tumors were also consistently immunoreactive for the RCC antigen (10 of 11) and CD10 (9 of 9), whereas cytokeratin and epithelial membrane antigen were negative in four cases and were positive focally in the others. Ultrastructurally, all of the six neoplasms examined showed features consistent with conventional-type (clear cell) renal carcinoma, although two demonstrated distinctive intracisternal microtubules. Both tumors tested contained PRCC-TFE3 fusion transcripts. The differential diagnosis includes conventional-type papillary renal cell carcinoma, conventional-type (clear cell) renal carcinoma, and the ASPL-TFE3 renal carcinomas associated with the t(X;17)(p11.2;q25), with the latter two being morphologically the most similar to the t(X;1) renal carcinomas. Aside from their distinctive clinicopathologic features described here, there is experimental evidence suggesting that these tumors may show differential sensitivity to certain chemotherapeutic agents.

Bronchoalveolar cells in children < 3 years old with severe recurrent wheezing

STUDY OBJECTIVE

To determine the cell profile of BAL from infants with severe recurrent wheezing who were not acutely ill at the time of investigation, suggesting an ongoing inflammation.

DESIGN AND PATIENTS

In a retrospective study, we determined BAL cell profiles for 83 children with wheezing aged 4 to 32 months (mean +/- SD, 11.3 +/- 5.5 months). Fiberoptic bronchoscopy was performed in children with severe recurrent wheezy bronchitis unresponsive to inhaled steroids. These children were compared with 17 children aged 6 to 36 months (mean, 15.1 +/- 7.5 months) with various nonwheezing pulmonary diseases. Children were included as control subjects if they had no endobronchial inflammation and no atopy.

RESULTS

The BAL cell profile of young children with wheezing typically includes a significantly higher cell count (mean, 644.4 +/- 956.8 x 10(3)/mL vs 313 +/- 203.2 x 10(3)/mL, p = 0.008), a significantly higher percentage of neutrophils (mean, 9 +/- 12.1% vs 2.1 +/- 2.2%, p = 0.003), and a higher neutrophil count (mean, 43.2 +/- 81.6 x 10(3)/mL vs 7.9 +/- 11.8 x 10(3)/mL, p = 0.003), as compared with control subjects. The larger number of neutrophils in children with wheezing was not correlated with bacterial or viral infection, or with age, sex, or atopic status. In contrast to the situation in asthmatic adults, eosinophil levels were not higher in children with wheezing than in control subjects (mean, 0.09 +/- 0.27% vs 0.08 +/- 0.25%).

CONCLUSION

Neutrophil-mediated inflammation in the airways appears to better characterize severe recurrent wheezing in children < 3 years old.

Severe cardiac involvement in children with systemic sclerosis and myositis

OBJECTIVE

To assess the outcome of children with systemic sclerosis (SSc) and features of polymyositis.

METHODS

The charts of 4 children who met the American College of Rheumatology criteria for SSc and had features of polymyositis, as defined by the presence of proximal muscle weakness and elevated serum creatine phosphokinase or aldolase level, were retrospectively reviewed.

RESULTS

All children had multivisceral involvement including (1) myocardial perfusion defects in all cases, with mild to severe dilated cardiomyopathy in 3; (2) lung restrictive syndrome in 3; (3) mild to severe esophageal involvement in all cases; and (4) severe intestinal dysfunction in one child. Combination therapy of corticosteroids, methotrexate (MTX), and cyclosporine resulted in improved skin thickness and muscle strength scores in all cases, as well as in lung restrictive syndrome in 2, but was not effective regarding the progression of intestinal malabsorption in one patient, esophageal dysmotility in 3 patients, and dilated cardiomyopathy in 3. Endstage cardiac failure caused 2 deaths. In one child, heart transplantation was performed for the first time in this indication.

CONCLUSION

Children with diffuse cutaneous SSc and features of polymyositis are prone to develop severe cardiomyopathy. Combination therapy of corticosteroids, MTX, and cyclosporine seems to be active on muscle, skin, and lung involvement but does not impair progression of esophageal or myocardial dysfunction. Heart transplantation might be considered, as an experimental treatment, in young patients with severe cardiomyopathy and no other irreversible organ damage.

Facial appearance in persistent hyperinsulinemic hypoglycemia

Persistent hyperinsulinism is the most common cause of recurrent hypoglycemia in infancy because of inappropriate oversecretion of insulin by the pancreas. Pancreatic lesions can be either focal or diffuse, and they have distinct molecular bases. We have studied the facial features in 17 unrelated patients presenting with neonatal (n = 8) or infancy-onset (n = 9) hyperinsulinism. Hyperinsulinism was related to focal adenomatous hyperplasia (n = 7), diffuse hyperinsulinism (n = 5), non-operated hyperinsulinism (n = 2), and hyperinsulinism with hyperammonemia (n = 3). SUR1 or Kir6.2 mutations were found in six of seven focal adenomatous hyperplasia and three of five diffuse hyperinsulinism. A loss of the maternal allele from chromosome 11p15 in the lesion was found in all focal adenomatous hyperplasia. GLUD1 mutations were found in all patients with hyperammonemia. Large birth weight (mean > 3,800 g) was consistently observed (11/17) but protruding tongue, exomphalos, or visceromegaly were never noted and Wiedemann-Beckwith syndrome could always be ruled out. All patients presented with high forehead, small nasal tip, and short columella giving the impression that the nose is large and bulbous, smooth philtrum, and thin upper lip. A square appearance to the face was more obvious in younger patients. These specific facial features, observed in patients with hyperinsulinism of various molecular mechanisms, could be the consequence of fetal intoxication by insulin. However, to date, facial anomalies have not been noted in infants of diabetic mothers and inversely, malformations that are commonly reported in infants of diabetic mothers were not present in our hyperinsulinemic patients.

ABCC8 (SUR1) and KCNJ11 (KIR6.2) mutations in persistent hyperinsulinemic hypoglycemia of infancy and evaluation of different therapeutic measures

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) can occur as a result of mutations in the subunits that form the ATP-sensitive potassium channel (K+ATP) in pancreatic beta-cells which play a major role in modulating insulin secretion from the beta-cells. Mutations have been shown in the genes for these subunits, namely for the plasma membrane sulfonylurea receptor (SUR1), ABCC8, and its associated inwardly rectifying potassium channel (KIR6.2) KCNJ11. Drugs which act on K+ATP channels, such as diazoxide, seem to need intact ABCC8 to be able to show their effects. Thus, it would be desirable to know the exact locus of the abnormality in the beta-cell to be able to choose the right therapeutic agent or to perform early pancreatectomy. The aim of this study was to search for the correlation between the mutations of the K+ATP channel and the outcome of therapeutic measures in patients with PHHI followed for a duration of 4 months to 7.3 years. Thirteen patients (5 F, 8 M) with PHHI with a median age of 2.5 months (8 days-12.1 years) were included in the study. Therapy for PHHI was initiated either with diazoxide (n = 9) or with calcium channel blocker (n = 4) as the agent of first choice. Three patients unresponsive to drugs underwent 95% pancreatectomy. Mutation analysis was performed by polymerase chain reaction (PCR) and single strand conformation polymorphism (SSCP) in DNA samples extracted from patients' peripheral leukocytes. The PCR products were directly sequenced. Screening of ABCC8 and KCNJ11 for mutations revealed abnormalities in the ABCC8 gene in three patients out of 13: homozygosity for the 155del1 mutation, compound heterozygosity for T267-->G/A4612-2-->G, and compound heterozygosity for G4310-->A/ R1494Q. No mutations in the KCNJ11 gene were identified. Of the three patients who underwent pancreatectomy, two had identified mutations and one did not have any known mutation. In two patients in whom hyperinsulinism recurred after surgery and in the rest of the children, therapy with either diazoxide or calcium channel blocker proved to be effective in controlling hypoglycemia over the follow-up period. Thus it may be concluded that mutations in the ABCC8 gene were not predictive of the response to drugs. Unidentified mutations in the K+ATP channels other than those screened or other functional abnormalities in these channels may account for the different therapeutic responses.

Osteopetrosis, lymphedema, anhidrotic ectodermal dysplasia, and immunodeficiency in a boy and incontinentia pigmenti in his mother

A child with X-linked osteopetrosis, lymphedema, anhidrotic ectodermal dysplasia, and immunodeficiency (OL-EDA-ID) was recently reported. We report the clinical features of a second boy with this novel syndrome and his mother, who presented with signs of incontinentia pigmenti (IP). The child had mild osteopetrosis without neurosensory complications, unilateral lymphedema of the left leg, and characteristic features of anhidrotic ectodermal dysplasia with sparse hair, facial dysmorphy, delayed eruption of teeth, and sweat gland abnormalities. He died at 18 months of severe immunodeficiency with multiple infections caused by Gram-negative (Salmonella enteritidis) and Gram-positive (Streptococcus pneumoniae) bacteria, nontuberculous mycobacteria (Mycobacterium kansasii), and fungi (Pneumocystis carinii). His 30-year-old mother's medical history, together with residual cutaneous lesions, was highly suggestive of IP without neurologic impairment. In this patient with OL-EDA-ID, we detected the same NF-kappaB essential modulator stop codon hypomorphic mutation identified in the previous patient. The occurrence of the same clinical features in 2 unrelated patients with the same genotype demonstrates that OL-EDA-ID is a genuine clinical syndrome. The clinical and biological descriptions of the proband and his mother further corroborate the relationship between IP and EDA. Both syndromes are allelic and are associated with mutations in NF-kappaB essential modulator, with a genotype-phenotype correlation in hemizygous males. In contrast, loss-of-function mutations and hypomorphic mutations may cause IP in females.

Association between Staphylococcus aureus strains carrying gene for Panton-Valentine leukocidin and highly lethal necrotising pneumonia in young immunocompetent patients

BACKGROUND

Between 1986 and 1998, eight cases of community-acquired pneumonia due to Staphylococcus aureus strains carrying the gene for the Panton-Valentine leukocidin (PVL) were recorded in France, six of which were fatal. We aimed to assess the clinical features of these eight cases, and those of other cases identified prospectively, and to compare them with the characteristics of patients with pneumonia caused by PVL-negative strains.

METHODS

We compared eight retrospective and eight prospective cases of PVL-positive S aureus pneumonia with 36 cases of PVL-negative S aureus pneumonia. For all patients, we recorded age, length of hospital stay, risk factors for infection, signs and symptoms, laboratory findings, antibiotic treatment, and serial radiological findings.

FINDINGS

Median age was 14.8 years (IQR 5.4-24.0) for the PVL-positive patients and 70.1 years (59.2-81.4) for the others (p=0.001). Influenza-like illness had occurred during the 2 days before admission in 12 of the 16 PVL-positive patients, but in only three of 33 PVL-negative patients (p<0.001). PVL-positive infections were more often marked by: temperature greater than 39 degrees C (p=0.01), heart rate above 140 beats per min (p=0.02), haemoptysis (p=0.005), onset of pleural effusion during hospital stay (p=0.004), and leucopenia (p=0.001). The survival rate 48 h after admission was 63% for the PVL-positive patients and 94% for PVL-negative individuals (p=0.007). Histopathological examination of lungs at necropsy from three cases of necrotising pneumonia associated with PVL-positive S aureus showed extensive necrotic ulcerations of the tracheal and bronchial mucosa and massive haemorrhagic necrosis of interalveolar septa.

INTERPRETATION

PVL-producing S aureus strains cause rapidly progressive, haemorrhagic, necrotising pneumonia, mainly in otherwise healthy children and young adults. The pneumonia is often preceded by influenza-like symptoms and has a high lethality rate.

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.

Heterogeneity of persistent hyperinsulinaemic hypoglycaemia. A series of 175 cases

Hyperinsulinism is a heterogeneous disorder characterised by severe hypoglycaemia due to an inappropriate oversecretion of insulin. In a personal series of 175 patients investigated for hyperinsulinaemic hypoglycaemia over the last 20 years, we review clinical presentations, molecular studies and therapeutic management of hyperinsulinism. There were 98 neonatal-onset patients, including 86 permanent hyperinsulinism and 12 transient forms, 68 with infancy-onset and nine with childhood-onset. Hyperammonaemia was found in 12 out of 69 patients tested, 4 neonates and 8 infants. Neonates were clinically more severely affected than infants. Diagnosis of infancy-onset hyperinsulinism was often delayed because of less profound hypoglycaemia and better tolerance to hypoglycaemia. Neonates required higher rates of i.v. glucose than infants to maintain normal plasma glucose levels (16 mg/kg per min versus 12 mg/kg per min). Only 16% of neonates were diazoxide-sensitive compared to 66% of the infants. Neonates with hyperammonaemia or transient hyperinsulinism were diazoxide-sensitive. Most neonates were pancreatectomised whereas 65% of the infants were treated medically. Among surgically-treated patients, 47% had a focal adenomatous hyperplasia (31 neonates and 13 infants) and 53% a diffuse form of hyperinsulinism (39 neonates and 11 infants). Diazoxide-responsiveness in the focal and diffuse forms did not differ in both neonates and infants; it depended only upon the age of onset of hypoglycaemia. One or two mutations, SUR1 or KIR6.2, were found in 41 of 73 neonates who were investigated and in 13/38 infants using polymerase chain reaction-single strand conformational polymorphism analysis of both genes. Almost all patients with SUR1 (38/41) or KIR6.2 (5/7) mutations were resistant to diazoxide. Ten patients with hyperinsulinism-hyperammonaemia syndrome had a mutation in the glutamate dehydrogenase gene (three neonates and seven infants) after reverse transcriptase-polymerase chain reaction and sequence analysis of cDNA. No mutation was found by polymerase chain reaction-single strand conformational polymorphism in the glucokinase gene. Eight of nine patients with childhood onset hyperinsulinism were treated surgically and histological examination confirmed an adenoma in each case.

CONCLUSION

the clinical severity of hyperinsulinism varies mainly with age at onset of hypoglycaemia. The heterogeneity of hyperinsulinism has major consequences in terms of therapeutic outcome and genetic counselling.

Pancreatic arterial calcium stimulation in the diagnosis and localisation of persistent hyperinsulinemic hypoglycaemia of infancy

BACKGROUND

Persistent hyperinsulinemic hypoglycaemia of infancy (PHHI) is often resistant to medical therapy. Surgery is therefore necessary. It is due to focal adenomatous islet-cell hyperplasia treatable by partial pancreatectomy, or diffuse beta-cell hyperfunction, which requires near-total pancreatectomy. Pancreatic venous sampling (PVS) is the reference technique for the preoperative diagnosis and localization of focal forms of PHHI in the pancreas. However, hypoglycaemia is necessary to analyse the results and PVS is technically challenging. Pancreatic arterial calcium stimulation (PACS) is technically easier and does not require hypoglycaemia.

AIM

To study the accuracy in the diagnosis and localization of PHHI.

MATERIALS AND METHODS

PACS was performed in 12 patients and correlated with histology.

RESULTS

The accuracy of PACS is poor in diffuse lesions since only two of six cases were correctly identified by this test. Five of six focal lesions were correctly recognized and located.

CONCLUSIONS

PACS is less accurate than PVS in PHHI. Currently, it should be performed only when PVS fails.