Familial visceral myopathy: a family with at least six involved members

Fluoroscopic Evaluation of Duodenal Diseases

The duodenum can be affected by a variety of abnormalities because of its development during embryogenesis and its dual intra- and retroperitoneal location. If small bowel embryogenesis is disturbed, congenital errors occur. Although some congenital variants may be asymptomatic and inconsequential to the patient, other anomalies can result in life-threatening emergencies such as malrotation, leading to midgut volvulus. Many infectious processes affect the duodenum, including duodenal ulcers and opportunistic infection in patients with HIV/AIDS or Crohn disease. Small bowel malignancies are uncommon but important to recognize, because the duodenum can be involved in polyposis syndromes or the development of primary adenocarcinoma, neuroendocrine tumors, lymphoma, and metastasis. Although endoscopy is currently the most used diagnostic method to assess the lumen of the upper gastrointestinal tract, fluoroscopy is a valuable adjunct technique and the study of choice for many diseases, specifically those for which anatomic and functional information is required. Fluoroscopy is also commonly used postoperatively to assess for complications such as obstruction and extraluminal leaks. Compared with endoscopy, fluoroscopy is an inexpensive and noninvasive technique that provides salient anatomic information and allows delineation of the duodenal mucosa and assessment of real-time duodenal motility. The authors examine the broad spectrum of conditions that can involve the duodenum, including congenital, infectious, inflammatory, and neoplastic abnormalities, and review their typical appearances at fluoroscopy. Online supplemental material is available for this article. ^©RSNA, 2022.

Prevalence and Clinicopathologic Features of Intestinal Perforation Caused by Segmental Absence of the Intestinal Musculature in Adults

Segmental absence of the intestinal musculature (SAIM) can cause intestinal perforation in adults. However, its prevalence and clinicopathologic features have not been well-described. This study aimed to determine the prevalence of SAIM-associated perforation and characterize its clinicopathologic features. We retrospectively examined 109 cases of intestinal perforation that underwent surgical resection from January 2009 to December 2019. SAIM was defined as the complete absence of the muscularis propria without extensive inflammation and fibrinous exudation around the perforation. SAIM was the second most frequent cause of perforation (26 cases: 24%), the most frequent cause being related to diverticulitis (39 cases: 36%). The most common site was the sigmoid colon (12 cases: 46.2%). The younger group (aged below 65 y) exhibited more frequent perforation of the upper segments of the gastrointestinal tract (from the duodenum to the descending colon) than the older group (65 y and above) (P=0.0018). No patients developed recurrence. The most common gross features were well-defined circular or small punched-out lesions, and the histologic features were complete absence of the muscularis propria and absence of hemorrhage and necrosis around the area of perforation. The characteristic features of SAIM were unique and their prevalence was higher than previously reported. The precise recognition of SAIM can aid in understanding the cause of perforation and avoiding further unnecessary examinations.

The management of adult patients with severe chronic small intestinal dysmotility

Adult patients with severe chronic small intestinal dysmotility are not uncommon and can be difficult to manage. This guideline gives an outline of how to make the diagnosis. It discusses factors which contribute to or cause a picture of severe chronic intestinal dysmotility (eg, obstruction, functional gastrointestinal disorders, drugs, psychosocial issues and malnutrition). It gives management guidelines for patients with an enteric myopathy or neuropathy including the use of enteral and parenteral nutrition.

Surgical treatment of megaduodenum in familial visceral myopathy - report of a case and review of the literature

INTRODUCTION

Familial visceral myopathy (VM) is a rare genetic disease that affects intestinal motility and results in pseudo-obstruction. Medical treatments can provide supportive measures but no curative treatment.

CASE REPORT

A 20-year-old male with known diagnosis of VM was referred to our Unit in May 2013 with recurrent episodes of vomiting and hospital admissions not responding to medical treatment. Pre-operative imaging showed megaduodenum with marked delayed transit and normal small and large bowel transit. He underwent an elective Roux-en-Y duodeno-jejunostomy. The post-operative course was uneventful with complete resolution of the symptoms with a 2 years follow-up.

DISCUSSION

Due to the early age of presentation, VM affects patient both psychologically and physically. Surgical treatment of megaduodenum in visceral myopathy in the absence of motility disorder of the small bowel seems to achieve satisfactory symptomatic relief and could be considered in this rare cohort of patients.

Phenotypic expansion of visceral myopathy associated with ACTG2 tandem base substitution

Familial visceral myopathy (FVM) is a rare heritable and heterogeneous condition due to impaired smooth muscle function. We identified a family segregating 11 individuals with a spectrum of visceral symptoms involving the small intestine, colon, biliary tract, urinary tract and uterus. Whole-exome sequencing revealed a novel heterozygous tandem base substitution c.806_807delinsAA (p.(Gly269Glu)) in ACTG2, encoding smooth muscle actin γ-2, in affected family members. Variants in ACTG2 were recently identified in FVM with intestinal pseudo-obstruction as well as with the congenital megacystics-microcolon-intestinal hypoperistalsis syndrome. In our family, eight affected members presented with severe complications from the biliary and/or the urinary tracts in addition to gastrointestinal pseudo-obstructions. Furthermore, all affected mothers had a history of assisted deliveries owing to poor progress during labor and weak uterine contractions. The variable involvement of multiple smooth muscle-dependent organs in our family, including the biliary tract and the uterus, add to the phenotypic spectrum associated with ACTG2 missense variants.

Segregation of a missense variant in enteric smooth muscle actin γ-2 with autosomal dominant familial visceral myopathy

BACKGROUND & AIMS

Familial visceral myopathy (FVM) is a rare inherited form of myopathic pseudo-obstruction; little is known about the genetic factors that cause this disorder. FVM is characterized by impaired functions of enteric smooth muscle cells, resulting in abnormal intestinal motility, severe abdominal pain, malnutrition, and even death. We searched for genetic factors that might cause this disorder.

METHODS

We performed whole-exome sequence analysis of blood samples from 2 individuals in a family that had 7 members diagnosed with FVM. Sanger sequencing was used to analyze additional family members and 280 individuals without this disorder (controls). Intestinal tissue samples from 4 patients and 2 controls were analyzed by immunohistochemistry. Functional studies, including immunofluorescence, cell contractility, and actomyosin structure analyses, were performed using CRL-1976 and U2OS sarcoma cell lines.

RESULTS

Whole-exome sequence analysis of DNA from 2 siblings identified 83 gene variants that were shared between the siblings and considered as possible disease-causing changes. A heterozygous variant, R148S in enteric smooth muscle actin γ-2 (ACTG2), segregated with disease phenotype. Intestinal smooth muscle (muscularis propria) from individuals with FVM had reduced levels of cytoplasmic ACTG2 and abnormal accumulation of the protein into intracellular inclusions compared with controls. Sarcoma cells that expressed exogenous ACTG2(R148S) incorporated reduced amounts of this protein into actin filaments compared with cells expressing ACTG2(wt) (P < .001). ACTG2(R148S) also interfered with actin cytoskeleton organization and the contractile activities of the cells, indicating a dominant-negative effect. These findings, along with the site of the variation in the protein, indicate that ACTG2 R148S interferes with actin filament assembly.

CONCLUSIONS

We identified the R148S variant in ACTG2 as a cause of FVM in one family. The altered ACTG2 protein appears to aggregate, rather than form actin filaments, in intestinal smooth muscle tissue. This defect could impair contraction of the visceral smooth muscle cells and reduce bowel motility.

Three-generation familial visceral myopathy with alpha-actin-positive inclusion bodies in intestinal smooth muscle

We report the clinical and histopathologic findings of a family with 7 affected members in 3 generations suffering from autosomal dominant visceral myopathy. All patients presented with chronic intestinal pseudo-obstruction affecting especially the entire small bowel. Histologic abnormalities involved intestinal smooth muscle, with degeneration and fibrosis of the muscularis propria. In addition, the inner circular layer of the muscularis propria contained alpha-smooth muscle actin-positive and, in more advanced disease, also periodic acid-Schiff-positive inclusion bodies. The inclusions were invisible in routine hematoxylin-eosin-stained sections, but were visible in immunohistochemical stainings for alpha-smooth muscle actin. No abnormality was evident in muscularis mucosae or in blood vessels, and the findings remained unidentified in mucosal biopsy specimens. To our knowledge, this is the first reported alpha-actin-positive inclusion body finding in familial visceral myopathy.

Smoothelin-a is essential for functional intestinal smooth muscle contractility in mice

BACKGROUND & AIMS

In patients with chronic intestinal pseudo-obstruction, intestinal motility is disturbed by either nervous or myogenic aberrations. The cause of the myogenic form is unknown, but it is likely to originate in the contractile apparatus of the smooth muscle cells. Smoothelins are actin-binding proteins that are expressed abundantly in visceral (smoothelin-A) and vascular (smoothelin-B) smooth muscle. Experimental data indicate a role for smoothelins in smooth muscle contraction. A smoothelin-deficient mouse model may help to establish the role of smoothelin-A in intestinal contraction and provide a model for myogenic chronic intestinal pseudo-obstruction.

METHODS

We used gene targeting to investigate the function of smoothelin-A in intestinal tissues. By deletion of exons 18, 19, and 20 from the smoothelin gene, the expression of both smoothelin isoforms was disrupted. The effects of the deficiency were evaluated by pathologic and physiologic analyses.

RESULTS

In smoothelin-A/B knockout mice, the intestine was fragile and less flexible compared with wild-type littermates. The circular and longitudinal muscle layers of the intestine were hypertrophic. Deficiency of smoothelin-A led to irregular slow wave patterns and impaired contraction of intestinal smooth muscle, leading to hampered transport in vivo. This caused obstructions that provoked intestinal diverticulosis and occasionally intestinal rupture.

CONCLUSIONS

Smoothelin-A is essential for functional contractility of intestinal smooth muscle. Hampered intestinal transit in smoothelin-A/B knockout mice causes obstruction, starvation, and, ultimately, premature death. The pathology of mice lacking smoothelin-A is reminiscent of that seen in patients with chronic intestinal pseudo-obstruction.

Deranged smooth muscle alpha-actin as a biomarker of intestinal pseudo-obstruction: a controlled multinational case series

BACKGROUND AND AIMS

Chronic idiopathic intestinal pseudo-obstruction (CIIP) is a severe motility disorder associated with significant morbidity. Several histopathological (neuropathic and myopathic) phenotypes have been described but only a single adult with jejunal smooth (circular) muscle alpha-actin deficiency. We present a prospective multinational case series investigating smooth muscle alpha-actin deficiency as a biomarker of this disease.

METHODS

A total of 115 fully clinically and physiologically (including prolonged (24 hour) ambulatory jejunal manometry) characterised CIIP patients from three European centres were studied. Immunohistochemical localisation of actins and other cytoskeletal proteins were performed on laparoscopic full thickness jejunal biopsies and compared with adult controls. Distribution of alpha-actin was also characterised in other gut regions and in the developing human alimentary tract.

RESULTS

Twenty eight of 115 (24%) CIIP patient biopsies had absent (n = 22) or partial (n = 6) jejunal smooth muscle alpha-actin immunostaining in the circular muscle layer. In contrast, smooth muscle alpha-actin staining was preserved in the longitudinal muscle and in adult jejunal controls (n = 20). Comparative study of other adult alimentary tract regions and fetal small intestine, suggested significant spatial and temporal variations in smooth muscle alpha-actin expression.

CONCLUSIONS

The ability to modulate alpha-smooth muscle actin expression, evident in development, is maintained in adult life and may be influenced by disease, rendering it a valuable biomarker even in the absence of other structural abnormalities.

Chronic intestinal pseudoobstruction syndrome: clinical analysis, outcome, and prognosis in 105 children. French-Speaking Group of Pediatric Gastroenterology

Our aim was to collect a large number of cases to characterize clinical presentation, outcome, and prognosis of chronic intestinal pseusoobstruction in children. We conducted a retrospective multicenter study that included children treated for chronic intestinal pseusoobstruction defined as recurrent episodes of intestinal obstruction with no mechanical obstruction, excluding Hirschsprung's disease. In all, 105 children, 57 boys and 48 girls, were studied, including five familial forms. Prenatal diagnosis was made in 18 patients. Eighty patients were less than 12 months old at onset; the disease began at birth for 37 patients. The most frequent signs were abdominal distension, vomiting, and constipation. Megacystis was noted in myopathies (7 cases), neuropathies (10 cases) and unclassified forms (13 cases). For all but three cases (two patients with CMV infection, one with Munchhausen-by-proxy syndrome), the associated diseases and disorders could not account for chronic intestinal pseusoobstruction as a secondary disorder. At least one full-thickness biopsy from the digestive tract was studied for 99 patients. The diagnosis recorded was visceral neuropathy in 58 cases, visceral myopathy in 17 cases, and uncertain or normal biopsy results in 24 cases. Seventy-eight children were fed intravenously, and only 18 were able to be fed orally throughout their illness. Seventy-one patients underwent surgery during their illness, and 217 surgical procedures, a mean of 3 per patient, were performed. Ostomy was the most performed procedure. Follow-up continued in 89 patients for 3 months to 16 years (mean 85 months). Forty-two patients were still fed by parenteral (39 patients) or enteral nutrition (3 patients) at the time of the study. Eleven patients died between the age of 1 month and 14 years 7 months.

Family studies of infantile visceral myopathy: a congenital myopathic pseudo-obstruction syndrome

We conducted family studies of a rare congenital myopathic pseudo-obstruction to provide recurrence risks to families of affected children. This infantile visceral myopathy (IVM) involves the smooth muscles of the digestive tract and frequently the urinary bladder. Family and pregnancy histories from 16 families were evaluated to identify possible environmental or genetic components. The families were ethnically and geographically diverse within the United States. Eleven of the children were alive, four had died, and the status of one was unknown. The sex ratio was 5 females to 11 males. The pregnancy histories provided no evidence of a teratogenic cause. In one family, the disorder passed from parent to child. There were no consanguineous matings, no similarly affected sibs, and except for one case, the family histories did not suggest affected relatives. We suspect a new dominant mutation may be responsible for some cases of IVM, whereas in others, IVM may be caused from a dominant gene with variable expressivity and incomplete penetrance. Therefore, we predict the recurrence risk of severely affected children is much less than the 25 or 50% risk sometimes given families based on the assumption of autosomal recessive or autosomal dominant inheritance. When counseling IVM families, a thorough family history is essential. Subsequent pregnancies should be monitored by ultrasound for megacystis that was detected prenatally in seven of these cases.

Clinical characteristics of chronic idiopathic intestinal pseudo-obstruction in adults

BACKGROUND

Chronic idiopathic intestinal pseudo-obstruction, a syndrome of ineffectual motility due to a primary disorder of enteric nerve or muscle, is rare.

AIMS

To determine the clinical spectrum, underlying pathologies, response to treatments, and prognosis in a consecutive unselected group of patients.

METHODS

Cross sectional study of all patients with clinical and radiological features of intestinal obstruction in the absence of organic obstruction, associated with dilated small intestine (with or without dilated large intestine), being actively managed in one tertiary referral centre at one time.

RESULTS

Twenty patients (11 men and nine women, median age 43 years, range 22-67) fulfilled the diagnostic criteria. Median age at onset of symptoms was 17 years (range two weeks to 59 years). Two patients had an autosomally dominant inherited visceral myopathy. Major presenting symptoms were pain (80%), vomiting (75%), constipation (40%), and diarrhoea (20%). Eighteen patients required abdominal surgery, and a further patient had a full thickness rectal biopsy. The mean time interval from symptom onset to first operation was 5.8 years. Histology showed visceral myopathy in 13, visceral neuropathy in three, and was indeterminate in three. In the one other patient small bowel motility studies were suggestive of neuropathy. Two patients died within two years of symptom onset, one from generalised thrombosis and the other from an inflammatory myopathy. Of the remaining 18 patients, eight were nutritionally independent of supplements, two had gastrostomy or jejunostomy feeds, and eight were receiving home parenteral nutrition. Five patients were opiate dependent, only one patient had benefited from prokinetic drug therapy, and five patients required formal psychological intervention and support.

CONCLUSIONS

In a referral setting visceral myopathy is the most common diagnosis in this heterogeneous syndrome, the course of the illness is usually prolonged, and prokinetic drug therapies are not usually helpful. Ongoing management problems include pain relief and nutritional support.

Oesophageal manometry in the evaluation of megacolon with onset in adult life

BACKGROUND

Oesophageal motility is often impaired in patients with megaduodenum and other forms of intestinal pseudo-obstruction in which a visceral myopathy or neuropathy may be present. Idiopathic longstanding megacolon with onset in adult life is still a poorly defined entity, which may also be part of a more widespread motility disorder but in which oesophageal motility has not been yet systematically studied.

AIMS

To assess oesophageal motility in patients with longstanding idiopathic megacolon with onset in adult life.

PATIENTS

14 consecutive subjects with idiopathic megacolon whose symptoms began after the age of 10 and a clinical history of 2-22 years.

METHODS

Standard barium enema, water perfused oesophageal manometry, and also anorectal manometry.

RESULTS

Oesophageal motility was impaired in five patients (36%; 95% confidence intervals 16 to 61%). Normal peristalsis was substituted by low amplitude multiple peaked simultaneous contractions in four subjects and by undetectable contractions in one. In three of them the lower oesophageal sphincter did not relax after swallows; in the same patients anal relaxation after rectal distension was also undetectable. All five patients with impaired oesophageal motility had a colonic dilatation sparing the rectum. Three of them reported constipation and a history of pesudo-obstruction and the other two only abdominal distension.

CONCLUSIONS

Oesophageal manometry should be performed in patients with longstanding idiopathic megacolon with onset in adult life, in particular if the rectum is not dilated and even in absence of pseudo-obstruction. This simple test may disclose a more widespread visceral neuropathy or myopathy. Such a diagnosis helps to better understand the cause of the colonic dilatation and may be clinically relevant for treatment of the patients.

A first report of familial visceral myopathy with additional chylous ascites in two siblings

BACKGROUND

Familial visceral myopathy in two siblings, involving the intestine with concurrent chylous ascites and chylous pleural effusion, is reported. In this connection a review of the recent gastroenterologic literature was performed.

PATIENTS

In two siblings, admitted between 1992 and 1995 with increasing ascites, loss of weight, and attacks of subileus, the diagnosis of familial visceral myopathy was established.

CASE ONE

During the initial preoperative examination hepatogenous ascites was diagnosed. Visceral myopathy and chylous ascites were subsequently established by means of an explorative laparotomy in conjunction with histologic examination of specimens taken from the small-bowel wall.

CASE TWO

The patient's brother was admitted 3 years later with similar symptoms. Complaints of chylous ascites and chylous pleural effusion in connection with attacks of subileus are still present.

OUTCOME

The female sibling was discharged from hospital with unchanged complaints and died only a few months later; the male sibling is still alive, but with unchanged complaints.

CONCLUSIONS

Rare cases of familial and sporadic myopathy have been reported in the recent literature, but to our knowledge these are the first cases with concurrent chylous ascites and chylous pleural effusion in this uncommon disorder.

Familial visceral myopathy associated with a mitochondrial myopathy

A 27 year old man with intestinal pseudo-obstruction who developed parenteral nutrition induced hyperlipidaemia and who also had ophthalmoplegia and an undifferentiated myopathy is described. Histological examination of biopsy specimens and molecular analysis show that this patient had both familial visceral myopathy and a mitochondrial myopathy, suggesting that a mitochondrial DNA mutation is the molecular lesion in familial visceral myopathy.

Intestinal pseudo-obstruction with deficient smooth muscle alpha-actin

We describe a 48-year-old woman with chronic constipation since early childhood who has an intestinal myopathy associated with a hitherto undescribed absence by immunostaining of smooth muscle alpha-actin confined to the intestinal circular muscle. There were no abnormalities in other contractile proteins (myosin, tropomyosin, filamin, caldesmon or desmin) and despite the abnormality of a contractile protein isoform in the circular muscle, no significant morphological changes were identified by light microscopy or ultrastructural examination. A possible developmental mechanism for the observed change is proposed. The use of specific antibodies to isoforms of contractile proteins may have potential value in the study of intestinal myopathies.

The small intestine and colon: scintigraphic quantitation of motility in health and disease

Radioisotopes allow accurate quantitation of the pattern and effectiveness of the transit of chyme through the small and large intestines. Abnormalities of small bowel transit can be demonstrated in patients with the irritable bowel syndrome, and patients with chronic idiopathic intestinal pseudo-obstruction due to either a visceral myopathy or neuropathy. In the colon, radioisotopic studies of transit have demonstrated the site of delayed transit in some severely constipated patients. In patients with these disorders of transit, functional studies may influence the choice of medical or surgical therapy although there are few prospective studies which have established their worth in this context. Radioisotope studies can also be utilised to study the effectiveness of delivery of drugs to the small and large bowel, and to study the adequacy of rectal evacuation in patients with a defaecatory disturbance. The low radiation dose and possibility of frequent observations make radioisotope studies valuable for clinical and research studies in functional gastrointestinal disorders.

Familial visceral myopathy. A family with involvement of four generations

A family with the autosomal dominant form of familial visceral myopathy is described involving four generations. The members illustrate several different clinical presentations including severe constipation, diarrhea, alternating constipation and diarrhea, volvulus, urinary tract infection, and retention of urine. One patient's history suggested that the uterus may have been involved. Diagnosis of this rare disease requires an awareness of the variable presentation and a careful histological examination of full-thickness sections of bowel. The potential pitfalls in both histological and clinical diagnosis of this condition are demonstrated in this family's history. The extensive involvement of small and large bowel in at least two family members is unusual in the autosomal dominant form of the disease, but their course has so far been favorable, lending further evidence to the impression that prognosis is good. This is of importance for genetic counseling of families who have this very rare disease.

Neuromuscular disease of the gastrointestinal tract

Gastrointestinal motility is the function of gastrointestinal smooth muscle. It is controlled by both the intrinsic and extrinsic nerves of the gastrointestinal tract and, to a lesser degree, the gastrointestinal hormones. Therefore, any abnormality of the above factors, theoretically, can cause gastrointestinal dysmotility. In a clinical situation, commonly seen is gastrointestinal dysmotility caused by either smooth muscle or intrinsic and extrinsic nerves dysfunction. Diseases that cause smooth muscle dysfunction include familial visceral myopathies, nonfamilial visceral myopathies, collagen disease, muscular dystrophies, amyloidosis, thyroid disease, and so on. Diseases that cause enteric nerve dysfunction include familial visceral neuropathies, nonfamilial visceral neuropathies, diabetes mellitus, Chagas' disease, ganglioneuromatosis of the intestine, visceral neuropathy of carcinomatosis, Parkinson's disease, and so on. The patients with neuromuscular disease of the gastrointestinal tract have a wide range of clinical manifestations regardless of the underlying cause. At one end of the spectrum, the patients may be asymptomatic, and at the other end of the spectrum, the patients may have functional obstruction of the gastrointestinal tract. Plain abdominal x-rays, upper gastrointestinal (UGI) and small bowel x-rays, enteroclysis, barium enema, and manometric studies are useful for the work-up of these patients. Enteroclysis is especially helpful in ruling out mechanical obstruction of the small intestine in patients with chronic intestinal pseudo-obstruction. Treatment is mainly symptomatic and supportive. There is no effective drug to improve gastrointestinal motility. Surgery may be helpful in selected cases of severe gastrointestinal dysmotility.