Syndromic HSCR Research Articles

An embryological point of view on associated congenital anomalies of children with Hirschsprung disease.

The most common congenital gut motility disorder is the Hirschsprung disease (HSCR). This anomaly is characterized by absence of neural crest-derived enteric neuronal ganglia. The aim of our study was to analyze the relationship between HSCR and other congenital anomalies or malfunctions. We examined 130 patients with Hirschsprung disease from Slovakia for last 10 years. During patients examination we focused not only on morphological abnormalities, but also functional anomalies. The incidence of associated congenital anomalies in our patients with HSCR was 26.1 %. But if we add functional defects (hypothyroidism, malfunction in cellular immunity, neurological deficit) to the morphological congenital abnormalities, the rate of the patients with HSCR with additional defects achieves 50.1 %. Nine of our patients (6.9 %) had syndromic HSCR. The most frequent disorder (13.6 % of patients) was primary deficiency in cellular immunity. More than 12.3 % of patients with HSCR had genitourinary abnormalities, in 10.0 % of patients variable degree of psychomotor retardation was observed, and skeletal, muscle and limb anomalies involved 7.7 % of patients. In 7.6 % cases of patients we found congenital hypothyroidism (including 2 cases of agenesis of thyroid gland). More than 6.1 % of patients presented with an associated anomaly in gastrointestinal tract (mostly anorectal malformations). Up to 5.5 % patients had congenital anomaly of heart, 3.8 % had ophthalmic and 3.1 % had craniofacial anomalies. Down syndrome was the main diagnosis in 3.8 % patients. We discussed the relationship between HSCR and other anomalies, which are probably caused by abnormal migration, proliferation, or differentiation, of neural crest cells during embryogenesis (Tab. 1, Fig. 2, Ref. 75).

Genome-Wide Copy Number Analysis Uncovers a New HSCR Gene: NRG3

Hirschsprung disease (HSCR) is a congenital disorder characterized by aganglionosis of the distal intestine. To assess the contribution of copy number variants (CNVs) to HSCR, we analysed the data generated from our previous genome-wide association study on HSCR patients, whereby we identified NRG1 as a new HSCR susceptibility locus. Analysis of 129 Chinese patients and 331 ethnically matched controls showed that HSCR patients have a greater burden of rare CNVs (p = 1.50×10−5), particularly for those encompassing genes (p = 5.00×10−6). Our study identified 246 rare-genic CNVs exclusive to patients. Among those, we detected a NRG3 deletion (p = 1.64×10−3). Subsequent follow-up (96 additional patients and 220 controls) on NRG3 revealed 9 deletions (combined p = 3.36×10−5) and 2 de novo duplications among patients and two deletions among controls. Importantly, NRG3 is a paralog of NRG1. Stratification of patients by presence/absence of HSCR–associated syndromes showed that while syndromic–HSCR patients carried significantly longer CNVs than the non-syndromic or controls (p = 1.50×10−5), non-syndromic patients were enriched in CNV number when compared to controls (p = 4.00×10−6) or the syndromic counterpart. Our results suggest a role for NRG3 in HSCR etiology and provide insights into the relative contribution of structural variants in both syndromic and non-syndromic HSCR. This would be the first genome-wide catalog of copy number variants identified in HSCR.

Association analysis of the SOX10 polymorphism with Hirschsprung disease in the Han Chinese population

Background Hirschsprung disease (HSCR, Online Mendelian Inheritance in Man 142623) is a typical developmental disorder of the enteric nervous system in which ganglion cells fail to innervate the lower gastrointestinal tract during embryonic development. SOX10 gene is involved in the normal development of the enteric nervous system. Heterozygous SOX10 mutations have been identified in patients with syndromic HSCR. However, no mutations have been reported to date to be associated to isolated HSCR patient. We thus sought to investigate whether mutations in the SOX10 are associated with isolated HSCR in the Chinese population. Methods Polymerase chain reaction amplification and direct sequencing were used to screen 4 exons of the SOX10 gene for mutations and polymorphisms in 104 patients with sporadic HSCR and 96 ethnically matched controls in Han Chinese populations. Results In this study, 4 single nucleotide polymorphisms (SNPs) were identified: SNP1: c.18C>T (GAC→GAT) in exon 2; SNP2: c.122G>T (GGC→GTC) in exon 2; SNP3: IVS2+10 (C→G) in intron 2; and SNP4: c.927T>C (CAT→CAC) in exon 4. SNP1 and SNP2 were novel described polymorphisms in the Chinese population. No SOX10 mutations were found in Han Chinese with isolated HSCR. Conclusions Our results revealed that there was no association between the 4 SNPs of the SOX10 gene and HSCR. This study showed that the SOX10 gene is unlikely to be a major HSCR gene in the Chinese Han population.

Practical pathology and genetics of Hirschsprung's disease

Diagnosis and management of Hirschsprung's disease (HSCR) requires understanding of the malformation's anatomic features and multigenic nature. Rectal biopsies, intraoperative frozen sections, and resection specimens provide invaluable information. Extraction of these data requires thoughtful biopsy technique, adequate histologic sections, histochemistry, and collaboration of surgeon and pathologist. Critical consideration of transition zone anatomy and published studies of "transition zone pull through" indicate that more research is needed to determine how much ganglionic bowel should be resected from HSCR patients. Many HSCR-susceptibility genes have been identified, but mutational analysis has limited practical value unless family history or clinical findings suggest syndromic HSCR.

Hirschsprung Disease and Congenital Anomalies of the Kidney and Urinary Tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) can be associated with Hirschsprung disease (HSCR). Based on the common genetic background of enteric nervous system and kidney development, the reported association of CAKUT and HSCR seems underestimated. Therefore, we designed a prospective study aimed at determining the prevalence of CAKUT in HSCR patients and at identifying RET, glial cell line-derived neurotrophic factor (GDNF), and GDNF family receptor alpha1 (GFRalpha1) mutations or haplotypes associated with this subset of HSCR patients. Eighty-four HSCR patients consecutively admitted to our department between July 2006 and July 2007 underwent interviews, notes review, ultrasound screening (further investigation according to detected anomaly), urinalysis, and DNA extraction for molecular genetics study. Another 27 patients with isolated CAKUT were included as a control group for the molecular genetics study. Twenty-one patients (25%) with HSCR had associated CAKUT, with hydronephrosis and hypoplasia being the most frequent diagnoses. Nine of 21 CAKUT were symptomatic. Six additional patients had other non-CAKUT anomalies (for example, stones, Barter syndrome) that were excluded from association and molecular genetics analysis to avoid bias of inclusion criteria. RET mutations were found in 5 patients (4 HSCR, 1 HSCR + CAKUT, 0 CAKUT) and GDNF mutations in 3 (2 HSCR, 1 CAKUT, 0 HSCR + CAKUT). No GFRalpha1 mutations were found. Finally, the HSCR-predisposing T haplotype of RET proto-oncogene was found in 64% of HSCR, 50% of HSCR + CAKUT, and in 24% of CAKUT patients. The incidence of CAKUT in HSCR patients is 4- to 6-fold higher than expected. Therefore, a patient with HSCR has a 3- to 18-fold higher risk of developing a CAKUT, particularly hydronephrosis or hypoplasia. If we consider that the proportion of predisposing haplotype in HSCR + CAKUT patients resembles that of other syndromic HSCR, we can conclude that HSCR + CAKUT has to be considered a novel syndromic association. These results need to be confirmed in a larger series. At present, we strongly suggest considering ultrasound screening of the urinary tract in every patient with a diagnosis of HSCR.

Complex pathogenesis of Hirschsprung's disease in a patient with hydrocephalus, vesico-ureteral reflux and a balanced translocation t(3;17)(p12;q11)

Hirschsprung's disease (HSCR), a congenital complex disorder of intestinal innervation, is often associated with other inherited syndromes. Identifying genes involved in syndromic HSCR cases will not only help understanding the specific underlying diseases, but it will also give an insight into the development of the most frequent isolated HSCR. The association between hydrocephalus and HSCR is not surprising as a large number of patients have been reported to show the same clinical association, most of them showing mutations in the L1CAM gene, encoding a neural adhesion molecule often involved in isolated X-linked hydrocephalus. L1 defects are believed to be necessary but not sufficient for the occurrence of the intestinal phenotype in syndromic cases. In this paper, we have carried out the molecular characterization of a patient affected with Hirschsprung's disease and X-linked hydrocephalus, with a de novo reciprocal balanced translocation t(3;17)(p12;q21). In particular, we have taken advantage of this chromosomal defect to gain access to the predisposing background possibly leading to Hirschsprung's disease. Detailed analysis of the RET and L1CAM genes, and molecular characterization of MYO18A and TIAF1, the genes involved in the balanced translocation, allowed us to identify, besides the L1 mutation c.2265delC, different additional factors related to RET-dependent and -independent pathways which may have contributed to the genesis of enteric phenotype in the present patient.

Epistatic interactions with a common hypomorphicRET allele in syndromic Hirschsprung disease

Hirschsprung disease (HSCR) stands as a model for genetic dissection of complex diseases. In this model, a major gene, RET, is involved in most if not all cases of isolated (i.e., nonsyndromic) HSCR, in conjunction with other autosomal susceptibility loci under a multiplicative model. HSCR susceptibility alleles can harbor either heterozygous coding sequence mutations or, more frequently, a polymorphism within intron 1, leading to a hypomorphic RET allele. On the other hand, about 30% of HSCR are syndromic. Hitherto, the disease causing gene has been identified for eight Mendelian syndromes with HSCR: congenital central hypoventilation (CCHS), Mowat-Wilson (MWS), Bardet-Biedl (BBS), Shah-Waardenburg (WS4), cartilage-hair-hypoplasia (CHH), Smith-Lemli-Opitz (SLO), Goldberg-Sprintzsen (GSS), and hydrocephalus due to congenital stenosis of the aqueduct of sylvius (HSAS). According to the HSCR syndrome, the penetrance of HSCR trait varies from 5 to 70%. Trisomy 21 (T21) also predisposes to HSCR. We were able to collect a series of 393 patients affected by CCHS (n = 173), WS4 (n = 24), BBS (n = 51), MWS (n = 71), T21 (n = 46), and mental retardation (MR) with HSCR (n = 28). For each syndrome, we studied the RET locus in two subgroups of patients; i.e., with or without HSCR. We genotyped the RET locus in 393 patients among whom 195 had HSCR, and compared the distribution of alleles and genotypes within the two groups for each syndrome. RET acts as a modifier gene for the HSCR phenotype in patients with CCHS, BBS, and Down syndrome, but not in patients with MWS and WS4. The frequent, low penetrant, predisposing allele of the RET gene can be regarded as a risk factor for the HSCR phenotype in CCHS, BBS, and Down syndrome, while its role is not significant in MWS and WS4. These data highlight the pivotal role of the RET gene in both isolated and syndromic HSCR.

Mutations of the RET gene in isolated and syndromic Hirschsprung’s disease in human disclose major and modifier alleles at a single locus

Background: In Hirschsprung’s disease (HSCR), a hypomorphic allele of a major gene, RET, accounts for most isolated (non-syndromic) cases, along with other autosomal susceptibility loci under a multiplicative model. However,...

Histopathological and immunohistochemical study of the enteric innervations among various types of aganglionoses including isolated and syndromic Hirschsprung disease

We investigated enteric innervations in 15 isolated and five syndromic cases of Hirschsprung disease (HSCR) with immunohistochemistry for the S100 protein (S100), class III a-tubulin (TUJ1), peripherin, neuronal nitric oxide synthase (nNOS) and CD34. The number of neurites per smooth muscle unit of the circular muscle layer (CML) was counted in the longitudinal sections. TUJ1 was the best marker to detect whole neuritic networks of the enteric nervous system. There were differences in the innervation patterns between isolated rectosigmoid aganglionosis (RS) and long segment aganglionosis (LS) including total colonic aganglionosis and extensive aganglionosis. In the aganglionic bowel (AGB) of LS, no nerve fibers innervated smooth muscle units in the CML in the area from the small bowel to the terminal descending colon. In the rectosigmoid region of every type of isolated HSCR, we observed transmural nerve fibers forming meshworks in the CML with TUJ1 and S100 antibodies. In RS, the neurites running parallel with smooth muscle cells gradually decreased in number in the distal portion. However, in the rectosigmoid AGB in LS, those neurites were absent and most neurites perpendicularly crossed the CML. Hypertrophic nerve trunks (HNT) in the submucous and myenteric plexuses were observed more frequently in the rectosigmoid region than in the rostral portion. Based on these data, it is suggested that the neuritic meshworks in the CML of the rectosigmoid AGB might derive from not only the sacral plexus, via HNT, but also intrinsic neurons in the oligoganglionic bowel. All of the syndromic HSCR were RS. In the AGB of RS with Down syndrome, the distribution of neurite meshworks in the CML is markedly reduced. In the AGB of RS with mental retardation suspected of having Mowat-Wilson syndrome, the density of intramuscular innervation was comparatively higher. In the rostral portion to the AGB of syndromic HSCR, myenteric ganglia were clearly small in size, and more numerous per smooth muscle unit with scarce internodal strands. These dysplastic features fall under neither hyperganglionosis nor hypoganglionosis classifications. We considered that syndromic HSCR might occur on the basis of a dysplastic enteric nervous system caused by genetic alteration.

Genome-wide linkage identifies novel modifier loci of aganglionosis in the Sox10Dom model of Hirschsprung disease

Hirschsprung disease (HSCR) is a complex disorder that exhibits incomplete penetrance and variable expressivity due to interactions among multiple susceptibility genes. Studies in HSCR families have identified RET-dependent modifiers for short-segment HSCR (S-HSCR), but epistatic effects in long-segment (L-HSCR) and syndromic cases have not been fully explained. SOX10 mutations contribute to syndromic HSCR cases and Sox10 alleles in mice exhibit aganglionosis and pigmentary anomalies typical of a subset of HSCR patients categorized as Waardenburg-Shah syndrome (WS4, OMIM 277580). Sox10 mutant alleles in mice exhibit strain-dependent variation in penetrance and expressivity of aganglionic megacolon analogous to the variation observed in patients with aganglionosis. In this study, we focused on enteric ganglia deficits in Sox10Dom mice and defined aganglionosis as a quantitative trait in Sox10Dom intercross progeny to investigate the contribution of strain background to variation in enteric nervous system deficits. We observe that the phenotype of Sox10Dom/+ mutants ranges over a continuum from severe aganglionosis to no detectable phenotype in the gut. To systematically identify genes that modulate Sox10-dependent aganglionosis, we performed a single nucleotide polymorphism-based genome scan in Sox10Dom/+ F1 intercross progeny. Our analysis reveals modifier loci on mouse chromosomes 3, 5, 8, 11 and 14 with distinct effects on penetrance and severity of aganglionosis. Three of these loci on chromosomes 3, 8 and 11 do not coincide with previously known aganglionosis susceptibility genes or modifier loci and offer new avenues for elucidating the genetic network that modulates this complex neurocristopathy.

Hirschsprung, RET-SOX and beyond: The challenge of examining non-mendelian traits (Review)

Hirschsprung disease (HSCR), or congenital intestinal aganglionosis, is a common hereditary disorder causing intestinal obstruction, thereby showing considerable phenotypic variation in conjunction with complex inheritance. Moreover, phenotypic assessment of the disease has been complicated since a subset of the observed mutations is also associated with several additional syndromic anomalies. Coding sequence mutations in e.g. RET, GDNF, EDNRB, EDN3, and SOX10 lead to long-segment (L-HSCR) as well as syndromic HSCR but fail to explain the transmission of the much more common short-segment form (S-HSCR). Furthermore, mutations in the RET gene are responsible for approximately half of the familial and some sporadic cases, strongly suggesting, on the one hand, the importance of non-coding variations and, on the other hand, that additional genes involved in the development of the enteric nervous system still await their discovery. For almost all of the identified HSCR genes incomplete penetrance of the HSCR phenotype has been reported, probably due to modifier loci. Therefore, HSCR has become a model for a complex oligo-/polygenic disorder in which the relationship between different genes creating a non-mendelian inheritance pattern still remains to be elucidated.

Segregation at three loci explains familial and population risk in Hirschsprung disease

Hirschsprung disease (HSCR), the most common hereditary cause of intestinal obstruction, shows considerable variation and complex inheritance. Coding sequence mutations in RET, GDNF, EDNRB, EDN3 and SOX10 lead to long-segment (L-HSCR) and syndromic HSCR but fail to explain the transmission of the much more common short-segment form (S-HSCR). We conducted a genome scan in families with S-HSCR and identified susceptibility loci at 3p21, 10q11 and 19q12 that seem to be necessary and sufficient to explain recurrence risk and population incidence. The gene at 10q11 is probably RET, supporting its crucial role in all forms of HSCR; however, coding sequence mutations are present in only 40% of linked families, suggesting the importance of noncoding variation. Here we show oligogenic inheritance of S-HSCR, the 3p21 and 19q12 loci as RET-dependent modifiers, and a parent-of-origin effect at RET. This study demonstrates by a complete genetic dissection why the inheritance pattern of S-HSCR is nonmendelian.

Large-Scale Deletions and SMADIP1 Truncating Mutations in Syndromic Hirschsprung Disease with Involvement of Midline Structures

Hirschsprung disease (HSCR) is a common malformation of neural-crest-derived enteric neurons that is frequently associated with other congenital abnormalities. The SMADIP1 gene recently has been recognized as disease causing in some patients with 2q22 chromosomal rearrangement, resulting in syndromic HSCR with mental retardation, with microcephaly, and with facial dysmorphism. We screened 19 patients with HSCR and mental retardation and eventually identified large-scale SMADIP1 deletions or truncating mutations in 8 of 19 patients. These results allow further delineation of the spectrum of malformations ascribed to SMADIP1 haploinsufficiency, which includes frequent features such as hypospadias and agenesis of the corpus callosum. Thus, SMADIP1, which encodes a transcriptional corepressor of Smad target genes, may play a role not only in the patterning of neural-crest-derived cells and of CNS but also in the development of midline structures in humans.