Persistent Müllerian duct syndrome associated with genetic defects in the regulatory subunit of myosin phosphatase

STUDY QUESTION

Can mutations of genes other than AMH or AMHR2, namely PPP1R12A coding myosin phosphatase, lead to persistent Müllerian duct syndrome (PMDS)?

SUMMARY ANSWER

The detection of PPP1R12A truncation mutations in five cases of PMDS suggests that myosin phosphatase is involved in Müllerian regression, independently of the anti-Müllerian hormone (AMH) signaling cascade.

WHAT IS KNOWN ALREADY

Mutations of AMH and AMHR2 are detectable in an overwhelming majority of PMDS patients but in 10% of cases, both genes are apparently normal, suggesting that other genes may be involved.

STUDY DESIGN, SIZE, DURATION

DNA samples from 39 PMDS patients collected from 1990 to present, in which Sanger sequencing had failed to detect biallelic AMH or AMHR2 mutations, were screened by massive parallel sequencing.

PARTICIPANTS/MATERIALS, SETTING, METHODS

To rule out the possibility that AMH or AMHR2 mutations could have been missed, all DNA samples of good quality were analyzed by targeted next-generation sequencing. Twenty-four samples in which the absence of AMH or AMHR2 biallelic mutations was confirmed were subjected to whole-exome sequencing with the aim of detecting variants of other genes potentially involved in PMDS.

MAIN RESULTS AND THE ROLE OF CHANCE

Five patients out of 24 (21%) harbored deleterious truncation mutations of PP1R12A, the gene coding for the regulatory subunit of myosin phosphatase, were detected. In addition to PMDS, three of these patients presented with ileal and one with esophageal atresia. The congenital abnormalities associated with PMDS in our patients are consistent with those described in the literature for PPP1R12A variants and have never been described in cases of AMH or AMHR2 mutations. The role of chance is therefore extremely unlikely.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of the study is the lack of experimental validation of the role of PPP1R12A in Müllerian regression. Only circumstantial evidence is available, myosin phosphatase is required for cell mobility, which plays a major role in Müllerian regression. Alternatively, PPP1R12A mutations could affect the AMH transduction pathway.

WIDER IMPLICATIONS OF THE FINDINGS

The study supports the conclusion that failure of Müllerian regression in males is not necessarily associated with a defect in AMH signaling. Extending the scope of molecular analysis should shed light upon the mechanism of the initial steps of male sex differentiation.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by la Fondation Maladies Rares, GenOmics 2021_0404 and la Fondation pour la Recherche Médicale, grant EQU201903007868. The authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Case Report: Jejunoileal Atresia With Persistent Poor Bowel Function Can Occur After Surgical Correction for Hirschsprung Disease

Jejunoileal atresia (JIA) is one of the common etiologies of intestinal obtrusion in neonates. However, cases of concomitant ileal atresia and Hirschsprung disease (HD) rarely occur. We report the case of a male infant who had JIA concomitantly with HD that was re-anastomosed. The patient underwent an exploratory laparotomy to resect the dilated terminal ileum. Subsequently, owing to a significantly dilated proximal bowel, he underwent a second exploratory laparotomy. However, he continued to have feeding intolerance postoperatively. He had colonic aganglionosis and was diagnosed with HD. A third laparotomy was then performed. Additionally, he had recurrent episodes of gram-negative bacteremia, especially candida parapsilosis fungemia, despite receiving antibiotics and antifungal, and there were no identifiable underlying genetic or immunological causes. Finally, the patient had recurrent episodes of hypoglycemia, central hypothyroidism, and multiple organ failure and died at the age of 7 months. The concomitant ileal atresia and HD was thought to be due to a common intrauterine vascular accident, together with loss of bowel, thereby acting as a barrier for the caudal migration of neuromeric cells and leading to colonic aganglionosis. In this case, ileal atresia was associated with colonic aganglionosis, central hypothyroidism, and persistent bacteremia, which is a unique finding. In cases of JIA, persistent poor bowel function after surgical correction of concomitant HD should be considered.

Ileal atresia and severe cerebral injury after fetoscopic laser photocoagulation treatment for twin-to-twin transfusion syndrome

BACKGROUND

Twin-to-twin transfusion syndrome (TTTS) is a significant cause of perinatal morbidity and mortality. Fetoscopic laser photocoagulation (FLP) is the optimal treatment option for twin-to-twin transfusion syndrome; but can cause central nervous system, extremity and intestinal system injury.

CASE

We report the case report of ileal atresia and severe cerebral infarction co-occurrence after fetoscopic laser photocoagulation treatment. It is uncertain as to whether ileal atresia occurred due to ischemia associated with TTTS, the treatment with FLP, or a combination of both.

CONCLUSIONS

Cases with prenatal ultrasonographic abnormalities after FLP should have a close assessment to detect bowel complications. Despite many developments in its management, TTTS remains an important risk factor for cerebral injury.

New sonographic feature (C-sign) to improve the prenatal accuracy of jejunal atresia

OBJECTIVES

To describe a new sonographic feature of the C-sign for prenatal diagnosis of jejunal atresia and evaluate its role in prenatal jejunal atresia, particularly preceding bowel dilatation and polyhydramnios.

METHODS

This was a retrospective study from a tertiary maternal hospital. Patients with prenatal sonographic examination and confirmed small bowel atresia postdelivery were included. All sonographic images were reviewed by two senior sonographers. Comparison of sonographic images between prenatal jejunal and ileal atresia using the C-sign resembles the shape of the entire duodenum and other traditional sonographic features. The control group without bowel atresia was assessed for the presence of the C-sign.

RESULTS

The C-sign and combined bowel dilatation with polyhydramnios were more frequent in jejunal atresia than ileal atresia, but the C-sign can be used to detect jejunal atresia earlier. The C-sign can be more likely to diagnose jejunal atresia in persisting bowel dilatation and polyhydramnios. The C-sign was not reported in any of the control fetuses.

CONCLUSION

The C-sign is a new sonographic feature that can be used to improve the prenatal accuracy and early detection of jejunal atresia. However, further prospective validation is needed.

Comparative Effectiveness of Imaging Modalities for the Diagnosis of Intestinal Obstruction in Neonates and Infants:: A Critically Appraised Topic

RATIONALE AND OBJECTIVES

The purpose of this study was to critically appraise and compare the diagnostic performance of imaging modalities that are used for the diagnosis of upper and lower gastrointestinal (GI) tract obstruction in neonates and infants.

METHODS

A focused clinical question was constructed and the literature was searched using the patient, intervention, comparison, outcome method comparing radiography, upper GI contrast study, and ultrasound in the detection of upper GI tract obstruction such as duodenal atresia and stenosis, jejunal and ileal atresia, and malrotation and volvulus. The same methods were used to compare radiography and contrast enema in the detection of lower GI tract obstruction such as meconium plug syndrome, meconium ileus, Hirschsprung disease, and imperforate anus. Retrieved articles were appraised and assigned a level of evidence based on the Oxford University Centre for Evidence-Based Medicine hierarchy of validity for diagnostic studies.

RESULTS

There were no sensitivities/specificities available for the imaging diagnosis of duodenal atresia or stenosis, jejunal or ileal atresias, meconium plug, and meconium ileus or for the use of cross-table lateral radiography for the diagnosis of rectal pouch distance from skin in imperforate anus. The retrieved sensitivity for the detection of malrotation on upper GI contrast study is 96%, and the sensitivity for the diagnosis of midgut volvulus on upper GI contrast study is 79%. The retrieved sensitivity and specificity for the detection of malrotation with volvulus on ultrasound were 89% and 92%, respectively. The retrieved sensitivity and specificity for the detection of Hirschsprung disease on contrast enema were 70% and 83%, respectively. The retrieved sensitivity of invertogram for the diagnosis of rectal pouch distance from skin in imperforate anus is 27%. The retrieved sensitivities of perineal ultrasound and colostography for the diagnosis of rectal pouch distance from skin in imperforate anus were 86% and 100%, respectively.

CONCLUSIONS

There is limited evidence for the imaging diagnosis of duodenal atresia and stenosis, jejunal and ileal atresias, meconium plug, meconium ileus, and imperforate anus, with recommended practice based mainly on low-quality evidence or expert opinion. The available evidence supports the use of upper GI contrast study for the diagnosis of malrotation and volvulus, with ultrasound as an adjunct to diagnosis. Contrast enema is useful in the investigation of suspected Hirschsprung disease, but a negative study does not outrule the condition. Colostography is the investigation of choice for the work-up of infants with complex anorectal malformations before definitive surgical repair.

Accuracy of prenatal ultrasound in detecting jejunal and ileal atresia: systematic review and meta-analysis

OBJECTIVE

The accuracy of prenatal ultrasound examination in detecting jejunal and ileal atresia has been reported in the literature to be highly variable, at 25-90%. The aim of this systematic review was to evaluate the accuracy of prenatal ultrasound in detecting non-duodenal small bowel atresia (ND-SBA).

METHODS

MEDLINE, EMBASE and The Cochrane Library, including The Cochrane Database of Systematic Reviews (CDSR), Database of Abstracts of Reviews of Effects (DARE) and The Cochrane Central Register of Controlled Trials (CENTRAL), were searched electronically. The overall detection rate of jejunal or ileal atresia using ultrasound was reported. The accuracy of using polyhydramnios and dilated loops of bowel as diagnostic signs was also explored.

RESULTS

Sixteen studies involving 640 fetuses were included in this review. The detection rate of ND-SBA by prenatal ultrasound was highly variable, with values ranging from 10 to 100%, with an overall prediction of 50.6% (95% CI, 38.0-63.2%). When analyzed separately, the detection rates of jejunal and ileal atresia were 66.3%, (95% CI, 33.9-91.8%) and 25.9% (95% CI, 4.0-58.0%), respectively. Both dilated loops of bowel and polyhydramnios as diagnostic signs for ND-SBA provided a low overall detection rate.

CONCLUSIONS

The diagnostic performance of prenatal ultrasound in identifying ND-SBA is extremely variable. Large studies are needed in order to identify objective and combined criteria for the diagnosis of these anomalies.

Ileal atresia with duplication cyst of terminal ileum: a rare association

A case of ileal atresia in association with duplication of terminal ileum is being reported here.