Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) in siblings: case report and review of the literature

The Diverse Phenotype of Intestinal Dysmotility Secondary to ACTG2-related Disorders

BACKGROUND AND AIMS

The initial description of a heterozygous dominant ACTG2 variant in familial visceral myopathy was followed by the identification of additional variants in other forms of intestinal dysmotility disorders. we aimed to describe the diverse phenotype of this newly reported and rare disease.

METHODS

Report of 4 new patients, and a systematic review of ACTG2-related disorders. we analyzed the population frequency and used in silico gene damaging predictions. Genotype-phenotype correlations were explored.

RESULTS

One hundred three patients (52% girls), from 14 publications, were included. Twenty-eight unique variants were analyzed, all exceedingly rare, and 27 predicted to be highly damaging. The median Combined Annotation Dependent Depletion (CADD) score was 29.2 (Interquartile range 26.3-29.4). Most patients underwent abdominal surgery (66%), about half required intermittent bladder catheterization (48.5%), and more than half were parenteral nutrition (PN)-dependent (53%). One-quarter of the patients died (25.7%), and 6 required transplant (5.8%). Girls had a higher rate of microcolon (P  = 0.009), PN dependency (P = 0.003), and death/transplant (P = 0.029) compared with boys, and early disease onset (<2 years of age) was associated with megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) features. There was no statistical association between disease characteristics and CADD scores.

CONCLUSIONS

Damaging ACTG2 variants are rare, often associated with MMIHS phenotype, and overall have a wide phenotypic variation. Symptoms usually present in the perinatal period but can also appear at a later age. The course of the disease is marked by frequent need for surgical interventions, PN support, and mortality. Poor outcomes are more common among girls with ACTG2 variants.

Consanguinity and its relevance for the incidence of megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS): systematic review

BACKGROUND/PURPOSE

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare congenital and generally fatal cause of functional intestinal obstruction in the newborn. The cause of this syndrome is unknown. Familial occurrence and reports of consanguinity in MMIHS implies that genetic factors may have an important role in the pathogenesis of this syndrome. The aim of the study was to determine the consequence of consanguinity for the incidence of MMIHS.

METHODS

A literature search was performed using the keywords "megacystis microcolon intestinal hypoperistalsis" for studies published between 1976 and 2018. Retrieved articles, including additional studies from reference lists, were reviewed for consanguinity between parents and recurrence of MMIHS between siblings. Data were extracted for cases where familial MMIHS was present.

RESULTS

A total of 450 patients with the diagnosis of MMIHS have been reported in the literature. There were 56 (12%) cases in which familial MMIHS was confirmed, 25 families with multiple siblings and 3 families with single affected infant. Of the 25 families with multiple siblings, 22 families had 2 siblings with confirmed MMIHS and 3 families had 3 children each with MMIHS. Consanguinity between parents was confirmed in 30 cases (18 siblings and 12 individual cases). Female-to-male ratio in the 30 patients was 4.4:1.

CONCLUSION

The occurrence of MMIHS in the offspring of consanguineous parents and recurrence in siblings of healthy parents suggest that MMIHS is an autosomal recessive disorder. Pre-marital and pre-conception counselling of consanguineous populations is recommended to prevent harmful consequences.

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome in Which a Different De Novo Actg2 Gene Mutation was Detected: A Case Report

INTRODUCTION

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is characterized by bladder distension without urinary tract obstruction, decreased or absent intestinal peristalsis and microcolon. Although the definitive cause remains unknown, changes in the ACTG2 gene are thought to be responsible for the intestinal and bladder hypoperistalsis.

CASE REPORT

This female newborn with MMIHS had a c.532C>A /p.Arg178Ser heterozygous de novo mutation detected in the ACTG2 gene. Normal immature ganglion cells, normal calretinin punctate positivity, maintence of smooth muscle actin immunoreactivity, and decreased numbers of interstitial cells of Cajal(ICCs) were detected.

CONCLUSION

This previously unreported c.532C>A /p.Arg178Ser heterozygous de novo mutation in the ACTG2 gene may lead to a severe form of MMIHS.

Advances in understanding functional variations in the Hirschsprung disease spectrum (variant Hirschsprung disease)

Hirschsprung disease (HSCR) is a fairly well understood congenital, genetically based functional obstruction due to the congenital absence of ganglion cells in the distal bowel. However, although over 90% of Hirschsprung cases conform to the normally accepted histological diagnostic criteria, it has become increasingly clear that in addition to HSCR, there is a group of functional disturbances relating to a number of other congenital neurodysplastic conditions causing some degree of gastrointestinal tract malfunction. Although these represent a variety of possibly separate conditions of the enteric nervous system, this spectrum it would appear to be also influenced by similar developmental processes. The term "variant Hirschsprung" is commonly used to describe these conditions, but ganglion cells are mostly present if abnormal in number and distribution. These conditions are a problem group being amongst the most difficult to diagnose and treat with possible practical and legal consequences. The problem appears to be possibly one of definition which has proven difficult in the relative paucity of normal values, especially when correlated to age and gestation. It is the purpose of this paper to review the current position on these conditions and to explore possible shared common pathogenetic and genetic mechanisms. This article explores those conditions where a similar pathogenetic mechanisms to HSCR can be demonstrated (e.g. hypoganglionosis) as well as other neural features, which appear to represent separate conditions possibly linked to certain syndromes.

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome: Case Reports and Discussion of the Literature

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare intestinal dysmotility condition that also involves a dilated urinary bladder. It was believed to be an autosomal recessive condition, but genetic studies have suggested possibly an autosomal dominant inheritance pattern. Prenatal diagnosis can be challenging, but MRI and amniotic fluid/digestive fluid studies may be complementary investigations to improve diagnostic accuracy. Prognosis of MMIHS is generally poor and treatment is mostly supportive. To date, bowel transplantation remains the only viable treatment to restore bowel motility. Here we present two additional cases to contribute towards the scant literature on this condition.

Megacystis microcolon intestinal hypoperistalsis syndrome: A report of a nationwide survey in Japan

BACKGROUND

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare condition with a poor outcome. A nationwide survey was conducted to identify the clinical features and outcomes of MMIHS in Japan.

METHODS

Data were collected via a questionnaire, which was sent to 353 pediatric/pediatric surgical departments in Japan.

RESULTS

Of the 28 patients registered as having a certain diagnosis of MMIHS, 19 (male/female, 3/16) patients were analyzed. All of the patients developed functional bowel obstruction in the neonatal period and showed a distended bladder and microcolon in the radiological examination. A histopathology assessment of the full-thickness of intestinal specimens showed no pathological abnormalities in all patients. Although various medications were given, the patients did not show significant improvement. Drainage stomas were created in the jejunum (n=11) and colon (n=5). Sixteen patients were maintained by parenteral nutrition (PN). Nine patients died of sepsis or liver failure. The five- and ten-year survival rates were 63% and 57%, respectively.

CONCLUSIONS

MMIHS patients developed severe functional intestinal obstruction in the neonatal period and had no specific therapeutic intervention. The majority of MMIHS patients required long-term PN. Small bowel or multivisceral transplantation may be necessary to improve the outcome of this condition.

Heterozygous de novo and inherited mutations in the smooth muscle actin (ACTG2) gene underlie megacystis-microcolon-intestinal hypoperistalsis syndrome

Megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disorder of enteric smooth muscle function affecting the intestine and bladder. Patients with this severe phenotype are dependent on total parenteral nutrition and urinary catheterization. The cause of this syndrome has remained a mystery since Berdon's initial description in 1976. No genes have been clearly linked to MMIHS. We used whole-exome sequencing for gene discovery followed by targeted Sanger sequencing in a cohort of patients with MMIHS and intestinal pseudo-obstruction. We identified heterozygous ACTG2 missense variants in 15 unrelated subjects, ten being apparent de novo mutations. Ten unique variants were detected, of which six affected CpG dinucleotides and resulted in missense mutations at arginine residues, perhaps related to biased usage of CpG containing codons within actin genes. We also found some of the same heterozygous mutations that we observed as apparent de novo mutations in MMIHS segregating in families with intestinal pseudo-obstruction, suggesting that ACTG2 is responsible for a spectrum of smooth muscle disease. ACTG2 encodes γ2 enteric actin and is the first gene to be clearly associated with MMIHS, suggesting an important role for contractile proteins in enteric smooth muscle disease.

Familial megacystis microcolon intestinal hypoperistalsis syndrome: a systematic review

BACKGROUND

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare and severe disorder of functional obstruction affecting bladder and bowel, usually diagnosed in the neonatal period. Over 230 cases have been reported since Berdon and colleagues first described this clinical entity in 1976. The exact pathogenesis of MMIHS is unknown. Familial occurrence of MMIHS has been reported and could offer insight into the aetiology of this disease. The purpose of this study was to systematically review the published literature for the evidence of familial MMIHS and to characterise these presentations.

METHODS

A literature search was performed using the keywords "megacystis microcolon intestinal hypoperistalsis" (1976-2013). Retrieved articles, including additional studies from reference lists, were reviewed for consanguinity between parents and recurrence of MMIHS between siblings. Data were extracted for cases where familial MMIHS was present.

RESULTS

A total of 47 patients were reported in which familial MMIHS was likely or confirmed. 15 sibling sets were definitively diagnosed with MMIHS (14 pairs and one set of three siblings). Four further index patients with a confirmed diagnosis and also one of the sibling pairs were reported to have a sibling in which MMIHS was probable. Consanguinity between parents was present in four of the confirmed sibling sets and in an additional seven individual cases. The outcome for familial MMIHS is generally poor. Multiple sibling fatalities were frequent and in only one family were both siblings' survivors at the time of reporting.

CONCLUSION

Consanguinity between parents and recurrence in siblings indicate that MMIHS is inherited in an autosomal recessive manner. With the advent of next generation sequencing, these familial clusters may be key to determining the genetic basis for MMIHS.

Classification and diagnostic criteria of variants of Hirschsprung's disease

"Variants of Hirschsprung's disease" are conditions that clinically resemble Hirschsprung's disease (HD), despite the presence of ganglion cells in rectal suction biopsies. The diagnosis and management of these patients can be challenging. Specific histological, immunohistochemical and electron microscopic investigations are required to characterize this heterogeneous group of functional bowel disorders. Variants of HD include intestinal neuronal dysplasia, intestinal ganglioneuromatosis, isolated hypoganglionosis, immature ganglia, absence of the argyrophil plexus, internal anal sphincter achalasia and congenital smooth muscle cell disorders such as megacystis microcolon intestinal hypoperistalsis syndrome. This review article systematically classifies variants of HD based on current diagnostic criteria with an additional focus on pathogenesis, epidemiology, clinical presentation, management and outcome.

Variants of Hirschsprung disease

Variants of Hirschsprung disease are conditions that clinically resemble Hirschsprung disease, despite the presence of ganglion cells in rectal suction biopsies. The characterization and differentiation of various entities are mainly based on histologic, immunohistochemical, and electron microscopy findings of biopsies from patients with functional intestinal obstruction. Intestinal neuronal dysplasia is histologically characterized by hyperganglionosis, giant ganglia, and ectopic ganglion cells. In most intestinal neuronal dysplasia cases, conservative treatments such as laxatives and enema are sufficient. Some patients may require internal sphincter myectomy. Patients with the diagnosis of isolated hypoganglionosis show decreased numbers of nerve cells, decreased plexus area, as well as increased distance between ganglia in rectal biopsies, and resection of the affected segment has been the treatment of choice. The diagnosis of internal anal sphincter achalasia is based on abnormal rectal manometry findings, whereas rectal suction biopsies display presence of ganglion cells as well as normal acetylcholinesterase activity. Internal anal sphincter achalasia is either treated by internal sphincter myectomy or botulinum toxin injection. Megacystis microcolon intestinal hypoperistalsis is a rare condition, and the most severe form of functional intestinal obstruction in the newborn. Megacystis microcolon intestinal hypoperistalsis is characterized by massive abdominal distension caused by a largely dilated nonobstructed bladder, microcolon, and decreased or absent intestinal peristalsis. Although the outcome has improved in recent years, survivors have to be either maintained by total parenteral nutrition or have undergone multivisceral transplant. This review article summarizes the current knowledge of the aforementioned entities of variant HD.

Megacystis microcolon intestinal hypoperistalsis syndrome: systematic review of outcome

PURPOSE

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare and the most severe form of functional intestinal obstruction in the newborn. This congenital condition is associated with non-obstructed urinary bladder, microcolon and decreased or absent intestinal peristalsis. This study was designed to determine the incidence and outcome of MMIHS.

METHODS

A systematic review of the literature (1976-2011) was performed for key words "megacystis microcolon intestinal hypoperistalsis". Resulting publications were reviewed for epidemiology and outcome. Reference lists were screened for additional cases.

RESULTS

A total number of 227 MMIHS cases were reported from 1976 to 2011. A clear preponderance for female infants was found (female 70.6 vs. male 29.4%). One or more surgical interventions were reported in 115 patients (including gastrostomy, ileostomy, jejunostomy, segmental resections of small bowel, adhesiolysis and internal sphincter myectomy). For decompression of the megacystis, vesicostomy was performed in 41 patients. Outcome was reported in a total of 218 patients. Survival rate was 19.7% (survivors: n = 43, non-survivors: n = 175), the oldest survivor being 24 years old. The vast majority of the surviving patients had to be maintained by total or partial parenteral nutrition (TPN). Main causes of death were sepsis, malnutrition and multiple organ failure. Twelve multivisceral transplantations have been reported to date in patients with MMIHS. The majority of the survivors are reported to be free of parenteral nutrition and show improving gastric emptying. However, intermittent catheterisation remains obligatory due to persistent bladder dysfunction.

CONCLUSIONS

The survival in MMIHS in recent years has improved. The majority of survivors are either maintained by TPN or have undergone multiorgan transplantations.

Normal oxidative phosphorylation in intestinal smooth muscle of childhood chronic intestinal pseudo-obstruction

BACKGROUND

Chronic intestinal pseudo-obstruction (CIPO) is a severe disease of the digestive tract motility. In pediatric population, CIPO remains of unknown origin for most patients. Chronic intestinal pseudo-obstruction is also a common feature in the course of mitochondrial oxidative phosphorylation disorders related for some patients to mutations in TYMP, POLG1, mtDNA tRNA(leu(UUR)) or tRNA(lys) genes. We hypothesized that CIPOs could be the presenting symptom of respiratory chain enzyme deficiency and thus we investigated oxidative phosphorylation in small bowel and/or colon smooth muscle of primary CIPO children.

METHODS

We studied eight children with CIPO and 12 pediatric controls. We collected clinical, radiological and pathological data and measured respiratory chain enzymatic activity in isolated smooth muscle of the small bowel and/or the colon. We also sequenced TYMP, POLG, mtDNA tRNA(leu(UUR)) and tRNA(lys) genes.

KEY RESULTS

Neither pathological nor radiological data were in favor of a mitochondrial dysfunction. No respiratory chain enzyme deficiency was detected in CIPO children. In myogenic CIPO, respiratory enzymes and citrate synthase activities were increased in small bowel and/or colon whereas no abnormality was noted in neurogenic and unclassified CIPO. Levels of enzyme activities were higher in control small bowel than in control colon muscle. Sequencing of TYMP, POLG, mtDNA tRNA(leu(UUR)) and tRNA(lys) genes and POLG gene did not reveal mutation for any of the patients.

CONCLUSIONS & INFERENCES

The normal enzymatic activities as the lack of radiological and genetic abnormalities indicate that, at variance with adult patients, oxidative phosphorylation deficiency is not a common cause of childhood CIPO.

Pathology of Intestinal Motor Disorders in Children

Varied intestinal neuromuscular pathologies are responsible for Hirschsprung disease and other forms of chronic pseudo-obstruction that are encountered in pediatrics. Pathologically distinct subtypes discussed in this review include aganglionosis, hypoganglionosis, neuronal intranuclear inclusion disease, ganglionitis, degenerative neuropathy, diffuse ganglioneuromatosis, neuronal dysplasia, malformations of the muscularis propria, degenerative leiomyopathy, leiomyositis, and mitochondriopathies. Emphasis is given to the histopathologic features that distinguish these conditions and their differential diagnoses.

Megacystis-microcolon-intestinal hypoperistalsis syndrome: a case report

Megacystis Microcolon Intestinal Hypoperistalsis Syndrom (MMIHS) is a quite rare congenital and fatal disease which was firstly defined by Berdon and his colleagues. It appears through a widely enlarged bladder and microcolon and its cause is unknown (Berdon et al., 1976; Carmelo et al., 2005; Makhija et al., 1999; Loening-Baucke and Kimura 1999; Redman et al., 1984; Hsu et al., 2003; Yigit et al., 1996; Srikanth et al., 1993). The disease is found in females three or four times more than in males (Srikanth et al., 1993; Sen et al., 1993; Hirato et al., 2003). Most of the cases die within the early months of their lives (Yigit et al., 1996; Srikanth et al., 1993; Sen et al., 1993; Hirato et al., 2003). We present the case of a female newborn with antenatal ultrasound revealing intestinal mass and bilateral hydroureteronephrosis. The case was admitted for intestinal obstruction after birth.

Prenatal diagnosis of intestinal pseudo-obstruction

The appearance of polyhydramnios and dilated bowel loops on prenatal sonographic examination usually implies mechanical obstruction. The prognosis is variable, depending on the etiology. Congenital pseudo-obstruction, a potentially lethal disease, comprises a group of disorders characterized by intestinal obstruction in the absence of an anatomic lesion. This report focuses on the prenatal diagnosis of intestinal pseudo-obstruction, and two cases of transient congenital intestinal pseudo-obstruction in one family are described. In both, the prenatal sonographic presentation was of small bowel obstruction. In one case there was postnatal suspicion of neurogenic bladder, and in the other there was unilateral hydronephrosis. The sonographic appearance of intestinal pseudo-obstruction is similar to that of mechanical obstruction. The clues to the prenatal diagnosis of pseudo-obstruction include associated urinary tract abnormalities and a family history of pseudo-obstruction.

Early prenatal diagnosis of concordant posterior urethral valves in male monochorionic twins

The association between monozygotic twins and posterior urethral valves (PUV) in postnatal life has been thoroughly described. In the fetus, the prenatal recognition of PUV is feasible. However, it has been repeatedly reported in singletons but never in monochorionic twins. We describe two cases of early prenatal diagnosis of concordant PUVs in monochorionic twins. In one of the sets, the expression of the disease was different for each twin.