Célia Crétolle

Spectrum of HLXB9 Gene Mutations in Currarino Syndrome and Genotype-Phenotype Correlation

Currarino syndrome (CS) is a rare congenital malformation described in 1981 as the association of three main features: typical sacral malformation (sickle‐shaped sacrum or total sacral agenesis below S2), hindgut anomaly, and presacral tumor. In addition to the triad, tethered cord and/or lipoma of the conus are also frequent and must be sought, as they may lead to severe complications if not treated. The HLXB9 gene, located at 7q36, is disease‐causing. It encodes the HB9 transcription factor and interacts with DNA through a highly evolutionarily conserved homeodomain early in embryological development. Thus far, 43 different heterozygous mutations have been reported in patients fulfilling CS criteria. Mutation detection rate is about 50%, and reaches 90% in familial cases. Here, we report 23 novel mutations in 26 patients among a series of 50 index cases with CS, and review mutational reports published since the identification of the causative gene. Three cytogenetic anomalies encompassing the HLXB9 gene are described for the first time. Truncating mutations (frameshifts or nonsense mutations) represent 57% of those identified, suggesting that haploinsufficiency is the basis of CS. No obvious genotype–phenotype correlation can be drawn thus far. Genetic heterogeneity is suspected, since at least 19 of the 24 patients without HLXB9 gene mutation harbor subtle phenotypic variations. Hum Mutat 29(7), 903–910, 2008.

Research perspectives in the etiology of congenital anorectal malformations using data of the International Consortium on Anorectal Malformations: evidence for risk factors across different populations

PurposeThe recently established International Consortium on Anorectal Malformations aims to identify genetic and environmental risk factors in the etiology of syndromic and nonsyndromic anorectal malformations (ARM) by promoting collaboration through data sharing and combined research activities.MethodsThe consortium attempts to recruit at least 1,000 ARM cases. DNA samples are collected from case–parent triads to identify genetic factors involved in ARM. Several genetic techniques will be applied, including SNP arrays, gene and whole exome sequencing, and a genome-wide association study. Questionnaires inquiring about circumstances before and during pregnancy will be used to obtain environmental risk factor data.ResultsCurrently, 701 ARM cases have been recruited throughout Europe. Clinical data are available from all cases, and DNA samples and questionnaire data mainly from the Dutch and German cases. Preliminary analyses on environmental risk factors in the Dutch and German cohort found associations between ARM and family history of ARM, fever during first trimester of pregnancy and maternal job exposure to cleaning agents and solvents.ConclusionFirst results show that both genetic and environmental factors may contribute to the multifactorial etiology of ARM. The International Consortium on Anorectal Malformations will provide possibilities to study and detect important genes and environmental risk factors for ARM, ultimately resulting in better genetic counseling, improved therapies, and primary prevention.

Value of 18F–fluoro-l-dopa PET in the Preoperative Localization of Focal Lesions in Congenital Hyperinsulinism

PURPOSE To retrospectively compare fluorine 18 ((18)F) fluoro-L-dopa positron emission tomography (PET) and pancreatic venous sampling (PVS) in the preoperative differentiation of diffuse from focal congenital hyperinsulinism (CHI) and localization of focal lesions. MATERIALS AND METHODS This study was approved by the institutional ethical committee, and informed consent for the research study was obtained from the parents of all subjects. Fifty-one patients evaluated for focal CHI between January 1, 1995, and January 31, 2008, were included. Thirty five underwent PVS evaluation alone, and 16 underwent a PET evaluation alone. The sensitivity values of each technique for the diagnosis and localization of focal lesions were compared in regard to results of surgery and pathologic analyses. In each patient, perioperative treatment was reviewed, and the presence of postoperative hypoglycemia was assessed as evidence of incomplete resection. Comparisons of the sensitivity values and recurrence rates were performed by using the Fisher exact test in regard to the number of patients. Comparisons of median age, weight, or number of biopsies were performed with a two-tailed unpaired Mann-Whitney U test. A difference with P < .05 was considered significant. RESULTS For PVS and PET groups, there was no error in differentiating focal from diffuse forms. PVS was not completed in four of 35 patients. In 27 (87%) of 31 patients in whom PVS was completed and 13 (81%) of 16 patients in whom PET was completed, preoperative localization of the focal lesion was in accordance with the surgical findings (P = .7). Although not significant, the number of biopsies performed before discovering the focal lesion was higher in the PET group compared with the PVS group (P = .06). Inadequate localization occurred in two (6%) patients in the PVS group and five (31%) patients in the PET group at initial preoperative imaging study; these patients underwent repeat surgery for residual CHI (P = .03). CONCLUSION (18)F-fluoro-L-dopa PET is equivalent to PVS in the characterization of CHI but does not provide localization of the lesion as precisely as does PVS.

The impact of anorectal malformations on anorectal function and social integration in adulthood: report from a national database.

The impact of anorectal malformation (ARM) on bowel function and social, educational and occupational end‐points was investigated in adult patients entered on a national database.

Dissection of the MYCN locus in Feingold syndrome and isolated oesophageal atresia

Feingold syndrome (FS) is a syndromic microcephaly entity for which MYCN is the major disease-causing gene. We studied the expression pattern of MYCN at different stages of human embryonic development and collected a series of 17 FS and 12 isolated oesophageal atresia (IOA) cases. An MYCN gene deletion/mutation was identified in 47% of FS cases exclusively. We hypothesized that mutations or deletions of highly conserved non-coding elements (HCNEs) at the MYCN locus could lead to its misregulation and thereby to FS and/or IOA. We subsequently sequenced five HCNEs at the MYCN locus and designed a high-density tiling path comparative genomic hybridization array of 3.3 Mb at the MYCN locus. We found no mutations or deletions in this region, supporting the hypothesis of genetic heterogeneity in FS.

Comprehensive review of the duplication 3q syndrome and report of a patient with Currarino syndrome and de novo duplication 3q26.32-q27.2

Partial duplications of the long arm of chromosome 3, dup(3q), are a rare but well‐described condition, sharing features of Cornelia de Lange syndrome. Around two thirds of cases are derived from unbalanced translocations, whereas pure dup(3q) have rarely been reported. Here, we provide an extensive review of the literature on dup(3q). This search revealed several patients with caudal malformations and anomalies, suggesting that caudal malformations or anomalies represent an inherent phenotypic feature of dup(3q). In this context, we report a patient with a pure de novo duplication 3q26.32‐q27.2. The patient had the clinical diagnosis of Currarino syndrome (CS) (characterized by the triad of sacral anomalies, anorectal malformations and a presacral mass) and additional features, frequently detected in patients with a dup(3q). Mutations within the MNX1 gene were found to be causative in CS but no MNX1 mutation could be detected in our patient. Our comprehensive search for candidate genes located in the critical region of the duplication 3q syndrome, 3q26.3‐q27, revealed a so far neglected phenotypic overlap of dup(3q) and the Pierpont syndrome, associated with a mutation of the TBL1XR1 gene on 3q26.32.

Impact of spinal dysraphism on urinary and faecal prognosis in 25 cases of cloacal malformation

OBJECTIVE Urinary and faecal continence are key challenges goal of cloacal malformation management. Most well-known prognostic factors are the length of common channel (CC) and the presence of a sacral defect, but the impact of associated spinal dysraphism is less well documented. The aim of this study was to investigate the impact of different types of dysraphism on urinary and faecal continence in this patient population. MATERIALS AND METHODS From 1991 to 2011, charts and office notes of 25 patients with cloacal malformation were retrospectively reviewed. At last clinic visit, urinary and faecal continence status according to Krickenbeck criteria were correlated with the length of CC, the presence of a sacral defect (sacral ratio), and the presence of different types of spinal cord dysraphism using magnetic resonance imaging (MRI) and Fishers exact test. RESULTS Mean follow-up was 8 years (4 months-21 years). The sacral ratio was abnormal (below 0.74) in 18 cases out of 25 (72%). MRI review showed normal spinal cord in eight out of 23 cases (Group 1), spinal cord anomaly in 15 out of 23 cases (65%) including nine cases of tethered cord complex (Group 2) and six cases of a short spinal cord (Group 3). While statistical analysis showed a difference regarding urinary prognosis between the groups (p=0.005), no significant difference was found regarding faecal prognosis. None of the six patients with short spinal cord were continent for both urinary and faecal prognosis. CONCLUSIONS This is the first study, which highlights the impact of different types of spinal dysraphism on functional outcome in patients with cloaca. Short spinal cord seemed to carry the worst prognosis. A prospective study with a larger series is mandatory to confirm these preliminary results.

The challenge of measuring quality of life in children with Hirschsprung's disease or anorectal malformation ☆

PURPOSE The aim of the present study was to assess, after adaptation to French, the only specific quality of life (QoL) instrument for children with Hirschsprungs disease or anorectal malformation, the Hirschsprungs disease/Anorectal Malformation Quality of Life questionnaire (HAQL), in order to get a standardized QoL evaluation instrument that could further be used to help health care improvement. METHODS The study was conducted in three teaching hospitals, including the French reference center for anorectal and pelvic malformations. After adaptation to French, QoL questionnaires were sent to the children and proxies. The questionnaire was mailed to 280 families. Psychometrics properties of the questionnaires (validity and reliability) were analysed from 120 proxy and 96 child questionnaires. RESULTS The HAQL with the original structure was not acceptable. Exploratory steps led to a clinically pertinent structure that had acceptable fit and good validity and reliability properties. The final structure pools physical symptoms (continence, discomfort) and psychosocial dimensions (general well-being, social and emotional functioning) of QoL. CONCLUSION The final structure, despite the disadvantage of being a new structure, allows assessment of QoL in this population and has the advantage of being shorter and validated on the clinical postoperative questionnaire from the Krickenbeck international consensus.

Think of the Conus Medullaris at the Time of Diagnosis of Fetal Sacral Agenesis.

Background: There is no precise prenatal indicator to refine an accurate prognosis in case of sacral agenesis and to define the diagnostic approach and outcome criteria in case of fetal sacral agenesis using 3 characteristics of the conus medullaris (CM): its position, its appearance, and associated spinal abnormalities. Methods: Ten cases of prenatally diagnosed sacral agenesis were included between 1995 and 2014 after collating ultrasound findings and prenatal computed tomography data. Results: Two cases of total sacral agenesis and 8 of partial agenesis were included. There were 1 or more spinal abnormalities in 8/10 cases: 6 lipomas, 4 low-lying tethered cords, 2 diastematomyelias, and 1 syringomyelia. Three situations were distinguished: sacral agenesis with low-lying tethered cord, sacral agenesis with a truncated CM, and sacral agenesis with CM in place. If the sacral agenesis is isolated, a lipoma should be sought. Lipomas of the filum have a good prognosis, whereas lipomas of the CM cause neurological deficits in 1/3 of cases. When there is a low-lying tethered cord, a diastematomyelia or a syringomyelia may be associated. In truncated CM, there may be a severe form suggestive of caudal regression syndrome. Serious ultrasound signs are immobility of the lower limbs, talipes equinovarus, impaired bladder emptying, and dilatation of the upper urinary tract. Conclusion: A precise description of the morphology of the CM, its position, and associated spinal malformations are important in defining the neurological, urinary, gastrointestinal, and motor functions prognosis in cases of fetal sacral agenesis.

Anti-LFA-1 antibody postpones T-cell receptor triggering while preserving generation of regulatory T cells in T-cell receptor anti-HY transgenic mice.

Background. Anti-LFA-1 (CD11a) antibody increases allograft survival and/or induces tolerance in murine models, but its mechanisms of action remain to be elucidated. Methods. Rag-2−/− H-2b recipient mice, bearing a transgenic T-cell receptor specific for the male antigen HY presented by MHC class II molecule, were transplanted with a C57BL/6 (H-2b) male heart with or without administration of anti-LFA-1 antibody from days −1 to 9. Results. Treatment prevented the transient episode of acute graft rejection observed in nontreated mice and maintained a naive phenotype and proliferative characteristics comparable to that of naive transgenic lymphocytes on day 7 during treatment, with decreased IFN-&ggr; mRNA and increased IL-4 mRNA. On day 14, phenotype and proliferative response of lymphocytes in treated mice was comparable to those of untreated animals. Furthermore, treatment did not interfere with the generation of CD4+V&bgr;6+CD25+ (Foxp3+) cells that were observed in long-term nontreated tolerant mice. Conclusions. This in vivo model demonstrates that anti-LFA-1 treatment induced a transient blockade of antigen recognition, which inhibited and postponed induction of signal 1 via the TCR and decreased the intensity of the Th1 response. Importantly, LFA-1 blockade did not disturb spontaneous generation of regulatory mechanism. This treatment would be compatible in clinical settings with other therapeutics inducing regulatory mechanisms.