Genome-wide high-density SNP-based linkage analysis of infantile hypertrophic pyloric stenosis identifies loci on chromosomes 11q14-q22 and Xq23

Evaluating the molecular and genetic mechanisms underlying gut motility disorders

INTRODUCTION

Gastrointestinal (GI) motility disorders comprise a wide range of different diseases affecting the structural or functional integrity of the GI neuromusculature. Their clinical presentation and burden of disease depends on the predominant location and extent of gut involvement as well as the component of the gut neuromusculature affected.

AREAS COVERED

A comprehensive literature review was conducted using the PubMed and Medline databases to identify articles related to GI motility and functional disorders, published between 2016 and 2023. In this article, we highlight the current knowledge of molecular and genetic mechanisms underlying GI dysmotility, including disorders of gut-brain interaction, which involve both GI motor and sensory disturbance.

EXPERT OPINION

Although the pathophysiology and molecular mechanisms underlying many such disorders remain unclear, recent advances in the assessment of intestinal tissue samples, genetic testing with the application of 'omics' technologies and the use of animal models will provide better insights into disease pathogenesis as well as opportunities to improve therapy.

Antibiotic-related adverse events in paediatrics: unique characteristics

Introduction: Antibiotics have saved and are still saving countless human lives from the burden of infectious diseases. However, as with all other drugs, they can cause adverse events. Generally, these are uncommon, mild and spontaneously resolving. However, in some cases, they can cause relevant clinical problems. Compared with adults, children, particularly in the first years of life, have a higher risk of antibiotic-related adverse events for several reasons. Areas covered: In this paper, the conditions that can contribute to the elevated risk of antibiotic-related adverse events in children are discussed. Expert opinion: Antibiotic stewardship can be a solution to limit antibiotic abuse and misuse and consequently the incidence of antibiotic-related adverse events in children. Moreover, most of the antibiotic-associated adverse events can be avoided with more extensive pre-marketing medicine investigations, improved postmarket safety surveillance system, increased transparency throughout the clinical research enterprise, increased training of clinical pharmacologists and paediatric researchers, expanded pool of paediatric patients, and providing additional funding and incentives for paediatric drug development.

The association of prenatal and postnatal macrolide exposure with subsequent development of infantile hypertrophic pyloric stenosis: a systematic review and meta-analysis

Background

The association between macrolides use and subsequent occurrence of infantile hypertrophic pyloric stenosis (IHPS) is still debatable. The aim of this study was to conduct a systematic review and meta-analysis of the association between perinatal exposure to macrolides, mainly erythromycin, and the development of pyloric stenosis.

Methods

Original studies were identified using MEDLINE, Web of Science, Scopus, Google Scholar, and the Cochrane Library databases. Studies investigating the association between perinatal exposure to macrolides and pyloric stenosis were included. The most adjusted effect estimates were pooled using random-effects meta-analysis. The I² and Egger’s tests were used to assess heterogeneity and publication bias, respectively.

Results

Fourteen papers (12 retrospective cohort studies and two case-control studies) were included. For postnatal exposure, the overall estimate of seven cohort studies indicated a statistically significant association (RR = 3.17, 95% CI: 2.38–4.23; I² = 10.0%) with no evidence of publication bias (Egger P = 0.81). For prenatal exposure, six cohort studies and two case-control studies were included. Meta-analysis demonstrated a statistically significant association in the cohort studies (OR = 1.47, 95% CI: 1.03–2.09; I² = 29.3%), but not in the case-control studies (OR = 1.02, 95% CI: 0.66–1.58; I² = 51.2%). The overall pooled result was not statistically significant. Only two studies were included for exposure through breastfeeding, and the estimates did not show a statistically significant association (OR = 1.31; 95% CI: 0.42–4.1; I² = 69.1%).

Conclusions

The study demonstrated good evidence of association between development of IHPS and direct postnatal exposure to macrolides. However, the evidence on the effects of prenatal exposure or postnatal maternal exposure (breastfeeding) is not conclusive.

A novel missense mutation in the transcription factor FOXF1 cosegregating with infantile hypertrophic pyloric stenosis in the extended pedigree linked to IHPS5 on chromosome 16q24

BACKGROUND

The aim was to identify susceptibility alleles for infantile hypertrophic pyloric stenosis (IHPS) in a pedigree previously linked to IHPS5 on chromosome 16q24.

METHODS

We screened the positional and functional candidate gene FOXF1 by Sanger sequencing in a single affected individual. All family members for whom DNA was available were genotyped to determine cosegregation status of the putative causal variant. Immunofluorescence studies were performed to compare the cellular localization of wildtype and mutant form of the protein. Transcriptional activity was compared using a luciferase assay.

RESULTS

A single novel substitution in FOXF1 (c.416G>A) predicted to result in a missense mutation (R139Q) was shown to cosegregate with disease trait. It was not seen in 560 control chromosomes nor has it been reported in ExAC or ESP. The R139Q substitution affects a conserved arginine residue within the DNA-binding domain of FOXF1. The transcriptional activity of the mutant FOXF1 protein is significantly reduced in comparison to wild-type.

CONCLUSION

These results provide strong evidence that the R139Q substitution in FOXF1 causes IHPS in this family and imply a novel pathological pathway for the condition. They further support a role for FOXF1 in the regulation of embryonic and neonatal development of the gastro-intestinal tract.

"TRP inflammation" relationship in cardiovascular system

Despite considerable advances in the research and treatment, the precise relationship between inflammation and cardiovascular (CV) disease remains incompletely understood. Therefore, understanding the immunoinflammatory processes underlying the initiation, progression, and exacerbation of many cardiovascular diseases is of prime importance. The innate immune system has an ancient origin and is well conserved across species. Its activation occurs in response to pathogens or tissue injury. Recent studies suggest that altered ionic balance, and production of noxious gaseous mediators link to immune and inflammatory responses with altered ion channel expression and function. Among plausible candidates for this are transient receptor potential (TRP) channels that function as polymodal sensors and scaffolding proteins involved in many physiological and pathological processes. In this review, we will first focus on the relevance of TRP channel to both exogenous and endogenous factors related to innate immune response and transcription factors related to sustained inflammatory status. The emerging role of inflammasome to regulate innate immunity and its possible connection to TRP channels will also be discussed. Secondly, we will discuss about the linkage of TRP channels to inflammatory CV diseases, from a viewpoint of inflammation in a general sense which is not restricted to the innate immunity. These knowledge may serve to provide new insights into the pathogenesis of various inflammatory CV diseases and their novel therapeutic strategies.

Regulation of TRP channels by steroids: Implications in physiology and diseases

While effects of different steroids on the gene expression and regulation are well established, it is proven that steroids can also exert rapid non-genomic actions in several tissues and cells. In most cases, these non-genomic rapid effects of steroids are actually due to intracellular mobilization of Ca(2+)- and other ions suggesting that Ca(2+) channels are involved in such effects. Transient Receptor Potential (TRP) ion channels or TRPs are the largest group of non-selective and polymodal ion channels which cause Ca(2+)-influx in response to different physical and chemical stimuli. While non-genomic actions of different steroids on different ion channels have been established to some extent, involvement of TRPs in such functions is largely unexplored. In this review, we critically analyze the literature and summarize how different steroids as well as their metabolic precursors and derivatives can exert non-genomic effects by acting on different TRPs qualitatively and/or quantitatively. Such effects have physiological repercussion on systems such as in sperm cells, immune cells, bone cells, neuronal cells and many others. Different TRPs are also endogenously expressed in diverse steroid-producing tissues and thus may have importance in steroid synthesis as well, a process which is tightly controlled by the intracellular Ca(2+) concentrations. Tissue and cell-specific expression of TRP channels are also regulated by different steroids. Understanding of the crosstalk between TRP channels and different steroids may have strong significance in physiological, endocrinological and pharmacological context and in future these compounds can also be used as potential biomedicine.

Association between NKX2-5 rs29784 and infantile hypertrophic pyloric stenosis in Chinese Han population

PURPOSE

The aim of this study was to evaluate the association of three single nucleotide polymorphisms (SNPs, rs11712066 and rs573872 near MBNL1, rs29784 near NKX2-5) with infantile hypertrophic pyloric stenosis (IHPS) in Chinese Han population.

METHODS

A total of 47 family trios consisting of infants with IHPS and their healthy biological parents were recruited for this study. Genotypes were determined using direct sequencing. Transmission disequilibrium test (TDT) was performed for family-based association analysis.

RESULTS

Genotypic distributions of three SNPs in both groups (patients and proband's parents) were in conformity with Hardy-Weinberg equilibrium (P > 0.05). There were significant preferential transmission of A allele of rs29784 from the parents to affected offspring (TDT: x(2) = 5.444, P = 0.0196). However, other two polymorphism loci (rs11712066 and rs573872) were not significant susceptibility loci for IHPS in Chinese Han population.

CONCLUSIONS

We found that there was a significant association between rs29784 and IHPS.

Etiology and non-surgical treatment of pyloric obstruction

Pyloric stenosis is a common type of upper gastrointestinal obstruction, which is a result of progression of many diseases. This paper will review the common causes of pyloric stenosis and its non-surgical treatments, mainly endoscopic treatment, in recent years. With the development of endoscopic technology, endoscopic treatment will gradually replace surgical treatment for treatment of pyloric obstruction.

Advances in infantile hypertrophic pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition in infancy, characterized by an acquired narrowing of the pylorus, which requires surgery. These infants usually present with projectile, nonbilious vomiting, with a palpable 'olive' in the abdomen and sometimes a 'peristaltic wave' after being fed with formula or breast milk. Although IHPS is a common disorder, its etiology is largely unknown. Surgical intervention is the standard treatment, preoperative preparation, however is essential to optimal outcome. In this review, the latest advances in IHPS regarding epidemiology, etiology, diagnostics and treatment will be discussed.

Hypertrophic pyloric stenosis in twins; genetic or environmental factors

The etiology of infantile hypertrophic pyloric stenosis (IHPS) remains obscure. Over 120 years after the condition has become a clinical entity the debate whether the cause of IHPS is genetic, environmental or both, has not yet reached a final conclusion. Herein, we present a pair of monozygotic male twins with IHPS together with a review of the literature. We aimed to support genetic pre-disposition in the epidemiology of IHPS, adding a twin data to the literature and to review the associated articles about the pathogenesis and inheritance patterns.

Genetic contribution to motility disorders of the upper gastrointestinal tract

Motility disorders of the upper gastrointestinal tract encompass a wide range of different diseases. Esophageal achalasia and functional dyspepsia are representative disorders of impaired motility of the esophagus and stomach, respectively. In spite of their variable prevalence, what both diseases have in common is poor knowledge of their etiology and pathophysiology. There is some evidence showing that there is a genetic predisposition towards these diseases, especially for achalasia. Many authors have investigated the possible genes involved, stressing the autoimmune or the neurological hypothesis, but there is very little data available. Similarly, studies supporting a post-infective etiology, based on an altered immune response in susceptible individuals, need to be validated. Further association studies can help to explain this complex picture and find new therapeutic targets. The aim of this review is to summarize current knowledge of genetics in motility disorders of the upper gastrointestinal tract, addressing how genetics contributes to the development of achalasia and functional dyspepsia respectively.

Confirmation of two novel loci for infantile hypertrophic pyloric stenosis on chromosomes 3 and 5

Infantile hypertrophic pyloric stenosis (IHPS) is a multifactorial heritable condition affecting infants in the first 3 months of life. It is characterized by hypertrophy of the pylorus resulting in blockage of the pyloric canal. Patients present with projectile vomiting, weight loss and dehydration. Five susceptibility loci have been identified through genome-wide linkage analysis and candidate gene approaches. The first genome-wide association study was recently performed and three statistically significant associations identified. Here, we report our confirmation of two of these significant results thus providing further support for new loci for IHPS on chromosome 3p25.1 and chromosome 5q35.2.

Infantile hypertrophic pyloric stenosis--genetics and syndromes

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition in neonates that is characterized by an acquired narrowing of the pylorus. The aetiology of isolated IHPS is still largely unknown. Classic genetic studies have demonstrated an increased risk in families of affected infants. Several genetic studies in groups of individuals with isolated IHPS have identified chromosomal regions linked to the condition; however, these associations could usually not be confirmed in subsequent cohorts, suggesting considerable genetic heterogeneity. IHPS is associated with many clinical syndromes that have known causative mutations. Patients with syndromes associated with IHPS can be considered as having an extreme phenotype of IHPS and studying these patients will be instrumental in finding causes of isolated IHPS. Possible pathways in syndromic IHPS include: (neuro)muscular disorders; connective tissue disorders; metabolic disorders; intracellular signalling pathway disturbances; intercellular communication disturbances; ciliopathies; DNA-repair disturbances; transcription regulation disorders; MAPK-pathway disturbances; lymphatic abnormalities; and environmental factors. Future research should focus on linkage analysis and next-generation molecular techniques in well-defined families with multiple affected members. Studies will have an increased chance of success if detailed phenotyping is applied and if knowledge about the various possible causative pathways is used in evaluating results.

Pre- and perinatal risk factors for pyloric stenosis and their influence on the male predominance

Pyloric stenosis occurs with a nearly 5-fold male predominance. To what extent this is due to environmental factors is unknown. In a cohort of all children born in Denmark, 1977-2008, the authors examined the association between pre- and perinatal exposures and pyloric stenosis and investigated whether these factors modified the male predominance. Information on pre- and perinatal factors and pyloric stenosis was obtained from national registers. Poisson regression models were used to estimate rate ratios. Among 1,925,313 children, 3,174 had surgery for pyloric stenosis. The authors found pyloric stenosis to be significantly associated with male sex, age between 2 and 7 weeks, early study period, being first born, maternal smoking during pregnancy, preterm delivery, small weight for gestational age, cesarean section, and congenital malformations. Among cases, 2,595 were males and 579 were females. Lower male predominance was associated with age at diagnosis outside the peak ages, early study period, no maternal smoking during pregnancy, preterm delivery, and congenital malformations. The authors have previously found a strong familial aggregation of pyloric stenosis indicating a genetic influence. This study shows that environmental factors during and shortly after pregnancy also play a role and that several of these modify the strong male predominance.

Genome-wide linkage analysis in families with infantile hypertrophic pyloric stenosis indicates novel susceptibility loci

Infantile hypertrophic pyloric stenosis (IHPS) is a common cause of upper gastrointestinal obstruction during infancy. A multifactorial background of the disease is well established. Multiple susceptibility loci including the neuronal nitric oxide synthase (NOS1) gene have previously been linked to IHPS, but contradictory results of linkage studies in different materials indicate genetic heterogeneity. To identify IHPS susceptibility loci, we conducted a genome-wide linkage analysis in 37 Swedish families. In regions where the Swedish material showed most evidence in favor of linkage, 31 additional British IHPS families were analyzed. Evidence in favor of significant linkage was observed in the Swedish material to two loci on chromosome 2q24 (non-parametric linkage (NPL) =3.77) and 7p21 (NPL=4.55). In addition, evidence of suggestive linkage was found to two loci on chromosome 6p21 (NPL=2.97) and 12q24 (NPL=2.63). Extending the material with British samples did not enhance the level of significance. Regions with linkage harbor interesting candidate genes, such as glucagon-like peptide-2 (GLP-2 encoded by the glucagon gene GCG), NOS1, motilin (MLN) and neuropeptide Y (NPY). The coding exons for GLP-2, and NPY were screened for mutations with negative results. In conclusion, we could confirm suggestive linkage to the region harboring the NOS1 gene and detected additional novel susceptibility loci for IHPS.

No association between the SNPs (rs56134796; rs3824934; rs41302375) in the TRPC6 gene promoter and infantile hypertrophic pyloric stenosis in Chinese people

PURPOSE

Our aim is to verify the association of three Single nucleotide polymorphisms (SNPs) (-218A/G, -254C/G, -361A/T) in the promoter of TRPC6 in 168 sporadic cases with infantile hypertrophic pyloric stenosis (IHPS) and 164 controls in Chinese people.

METHODS

All participants were genotyped using polymerase chain reaction and direct sequencing. And the χ(2) value was calculated. A value of P less than 0.05 was considered statistically significant. We also got the P value of Hardy-Weinberg equilibrium test, and the value of P greater than 0.05 was assumed to be at Hardy-Weinberg equilibrium in this population.

RESULTS

The results tell us that there are no significant differences in the allele and genotype frequencies of all these three SNPs between the case and the control groups (P > 0.05).

CONCLUSION

These three TRPC6 SNPs have no association with the IHPS in Chinese people. However, we cannot deny that TRPC6 would be a susceptible gene with IHPS in Chinese people. May be other SNPs in TRPC6 would have some association with the IHPS in Chinese people. But in this study our results may be due to the fact that these SNPs are not the functional SNPs for the development of IHPS in Chinese people.

Genomic variants in the coding region of neuronal nitric oxide synthase (NOS1) in infantile hypertrophic pyloric stenosis

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is a common childhood pathology affecting 1 to 5:1000 newborns, with a genetic background suggested by familial occurrence. Neuronal nitric oxide synthase (NOS1) is a candidate gene owing to its role in the relaxation of smooth musculature and the association of the -84g>a variant of NOS1 with IHPS.

METHODS

We investigated NOS1 through sequencing of the complete NOS1 coding region in DNA from 43 patients with IHPS compared the genotype frequencies to 47 controls using the Cochran-Armitage trend or Fisher exact tests.

RESULTS

We found 19 polymorphisms in the coding region of NOS1. The variants c.3827-42_3827-43 del_insTA and c.+276 c>t were more frequent in IHPS with statistically significant exact P values (P = .010 and P = .039, respectively) yet failed to show significance after Bonferroni adjustment for multiple testing. We have also found a marginally significant occurrence of the variants c.-460A (P = .065) and c.2823+15G (P = .076). There was a significant correlation between the variants c.2706C>T ⬄ c.2823+15A>G, (r(2) = 1.00) and c.3258 C>T ⬄ c.3235+31A>G (r(2) = 1.00).

CONCLUSIONS

We conclude that NOS1 variants are present in patients with IHPS yet show no significant statistical association with the IHPS phenotype, suggesting at best an adjuvant role for NOS1 in IHPS.

Infantile hypertrophic pyloric stenosis: evaluation of three positional candidate genes, TRPC1, TRPC5 and TRPC6, by association analysis and re-sequencing

Infantile hypertrophic pyloric stenosis (IHPS) is the most common inherited form of gastrointestinal obstruction in infancy with a striking male preponderance. Infants present with vomiting due to gastric outlet obstruction caused by hypertrophy of the smooth muscle of the pylorus. Two loci specific to extended pedigrees displaying autosomal dominant inheritance have been identified. A genome scan identified loci on chromosomes 11q14-q22 and Xq23-q24 which are predicted to be responsible for a subset of smaller families with IHPS demonstrating non-Mendelian inheritance. The two linked chromosomal regions both harbour functional candidate genes which are members of the canonical transient receptor potential (TRPC) family of ion channels. Both TRPC5 (Xq23-q24) and TRPC6 (11q14-q22) have a potential role in smooth muscle control and hypertrophy. Here, we report suggestive evidence for a third locus on chromosome 3q12-q25 (Zmax = 2.7, p < 0.004), a region which harbours a third TRPC gene, TRPC1. Fine mapping of all three genes using a tagSNP approach and re-sequencing identified a SNP in the promoter region of TRPC6 and a missense variant in exon 4 of TRPC6 which may be putative causal variants.

Epidemiological features of infantile hypertrophic pyloric stenosis in Taiwanese children: a Nation-Wide Analysis of Cases during 1997-2007

Objective

To describe the epidemiological characteristics of infantile hypertrophic pyloric stenosis (IHPS) in ethnic Chinese children.

Materials and Methods

We reviewed the National Health Insurance claims database and analyzed data from children less than one year of age who had been diagnosed with IHPS (ICD-9-CM 750.5) and had undergone pyloromyotomy (ICD-9-CM 43.3). We analyzed the incidence, gender, age at diagnosis, length of hospital stay, seasonal variation and cost of IHPS from data collected between January 1997 and December 2007.

Results

A total of 1,077 infants met inclusion criteria, including 889 boys and 188 girls. The annual incidence of IHPS ranged from 0.30 to 0.47 per 1,000 live births with a mean incidence of 0.39 per 1,000 live births. Between 2002 and 2007, the incidence showed a declining trend (P = 0.025) with coincidentally increasing trends for both exclusive breastfeeding (P = 0.014) and breastfeeding plus bottle feeding (P = 0.004). The male-to-female rate ratio was dynamic and increased from 3.03 during the first two weeks of life to 8.94 during the 8^th through 10^thweeks of life. The overall male-to-female rate ratio was 4.30. The mean age at diagnosis was 43.1±2.4 days. After analyzing the months of birth and hospital admission, no seasonal variation associated with IHPS was detected. The mean length of hospital stay was 8.28±7.10 days.

Conclusions

The incidence of IHPS in Taiwan, a country with a majority ethnic Chinese population, was lower than observed incidences in Caucasian populations living in Western countries. Breastfeeding campaigns and low maternal smoking rates may contribute to the lower incidence of IHPS in Taiwan. However, additional studies with longer follow-up periods are needed.

Lack of association between nNOS -84G>A polymorphism and risk of infantile hypertrophic pyloric stenosis in a Chinese population

BACKGROUND

Infantile hypertrophic pyloric stenosis (IHPS) is one of the most common gastrointestinal obstructions in the infancy requiring surgery. Reduced expression of neuronal nitric oxide synthase (nNOS), which plays an important role in the regulation of the human pyloric muscle, is thought to underlie IHPS. The role of nNOS in IHPS has been supported by the genetic association of a functional regulatory nNOS polymorphism (-84G>A) with IHPS in whites. We reasoned that the corroboration of this association in a population of different ethnic origin would prompt follow-up studies and further investigation of the IHPS pathology at molecular level. Thus, we attempted to reproduce the original findings in a Chinese population of comparable size in what would be the first genetic study on IHPS conducted in Chinese.

METHODS

nNOS -84G>A genotypes were analyzed in 56 patients and 86 controls by polymerase chain reaction and DNA sequencing. Logistic regression was used to compute odds ratios.

RESULTS

Our study could not corroborate the association previously reported. Although the frequency of the IHPS-associated allele (-84A) in controls (0.205) was similar to that reported for white controls, there was a dramatic difference in -84A frequencies between white and Chinese patients (0.198). Similarly, there was no difference in the nNOS -84G>A genotype distribution between patients and controls, even when the GA and AA genotypes were combined to compare GG genotype (odds ratio, 1.01; 95% confidence interval, 0.47-2.19).

CONCLUSIONS

Failure to replicate the initial finding does not detract from its validity, because genetic effects may differ across populations. Differences across populations in linkage disequilibrium and/or allele frequencies may contribute to this lack of replication. The role nNOS in IHPS awaits further investigation.

Transient receptor potential channelopathies

In the past years, several hereditary diseases caused by defects in transient receptor potential channels (TRP) genes have been described. This review summarizes our current knowledge about TRP channelopathies and their possible pathomechanisms. Based on available genetic indications, we will also describe several putative pathological conditions in which (mal)function of TRP channels could be anticipated.

New insights into the pathogenesis of infantile pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is the most common surgical cause of vomiting in infants. Despite numerous hypotheses, the aetiopathogenesis of IHPS is not fully understood. Genetic, extrinsic and hormonal factors have been implicated in the pathogenesis of the disease. Furthermore, abnormalities of various components of the pyloric muscle such as smooth muscle cells, growth factors, extracellular matrix elements, nerve and ganglion cells, synapses, nerve supporting cells, neurotransmitters and interstitial cells of Cajal have been reported. Recently, genetic studies have identified susceptibility loci for IHPS and molecular studies have concluded that smooth muscle cells are not properly innervated in IHPS.

Physiology and pathophysiology of canonical transient receptor potential channels

The existence of a mammalian family of TRPC ion channels, direct homologues of TRP, the visual transduction channel of flies, was discovered during 1995-1996 as a consequence of research into the mechanism by which the stimulation of the receptor-Gq-phospholipase Cbeta signaling pathway leads to sustained increases in intracellular calcium. Mammalian TRPs, TRPCs, turned out to be nonselective, calcium-permeable cation channels, which cause both a collapse of the cell's membrane potential and entry of calcium. The family comprises 7 members and is widely expressed. Many cells and tissues express between 3 and 4 of the 7 TRPCs. Despite their recent discovery, a wealth of information has accumulated, showing that TRPCs have widespread roles in almost all cells studied, including cells from excitable and nonexcitable tissues, such as the nervous and cardiovascular systems, the kidney and the liver, and cells from endothelia, epithelia, and the bone marrow compartment. Disruption of TRPC function is at the root of some familial diseases. More often, TRPCs are contributing risk factors in complex diseases. The present article reviews what has been uncovered about physiological roles of mammalian TRPC channels since the time of their discovery. This analysis reveals TRPCs as major and unsuspected gates of Ca(2+) entry that contribute, depending on context, to activation of transcription factors, apoptosis, vascular contractility, platelet activation, and cardiac hypertrophy, as well as to normal and abnormal cell proliferation. TRPCs emerge as targets for a thus far nonexistent field of pharmacological intervention that may ameliorate complex diseases.

Linkage of monogenic infantile hypertrophic pyloric stenosis to chromosome 16q24

Infantile hypertrophic pyloric stenosis (IHPS) is the most common inherited form of gastrointestinal obstruction in infancy. The disease is considered a paradigm for the sex-modified model of multifactorial inheritance and affects males four times more frequently than females. However, extended pedigrees consistent with autosomal dominant inheritance have been documented. We have analysed data from an extended IHPS family including eight affected individuals (five males and three females) and mapped the disease locus to chromosome 16q24 (LOD score=3.7) through an SNP-based genome wide scan. Fourteen additional multiplex pedigrees did not show evidence of linkage to this region, indicating locus heterogeneity.