Currarino syndrome: does the presence of a genetic anomaly correlate with a more severe phenotype? A multicentre study

Currarino syndrome: a comprehensive genetic review of a rare congenital disorder

Background

The triad of a presacral mass, sacral agenesis and an anorectal anomaly constitutes the rare Currarino syndrome (CS), which is caused by dorsal–ventral patterning defects during embryonic development. The major causative CS gene is MNX1, encoding a homeobox protein.

Main body

In the majority of patients, CS occurs as an autosomal dominant trait; however, a female predominance observed, implies that CS may underlie an additional mode(s) of inheritance. Often, the diagnosis of CS is established solely by clinical findings, impacting a detailed analysis of the disease. Our combined data, evaluating more than 60 studies reporting patients with CS-associated mutations, revealed a slightly higher incidence rate in females with a female-to-male ratio of 1.39:1. Overall, MNX1 mutation analysis was successful in only 57.4% of all CS patients investigated, with no mutation detected in 7.7% of the familial and 68% of the sporadic patients. Our studies failed to detect the presence of an expressed MNX1 isoform that might explain at least some of these mutation-negative cases.

Conclusion

Aside from MNX1, other genes or regulatory regions may contribute to CS and we discuss several cytogenetic studies and whole-exome sequencing data that have implicated further loci/genes in its etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01799-0.

Currarino Syndrome: A Rare Condition With Potential Connection to Neuroendocrine Tumors

OBJECTIVES

Currarino syndrome (CS) is a congenital disorder that consists of a triad of anomalies: presacral mass, sacral dysgenesis, and anorectal malformations. Few cases of CS with neuroendocrine tumors (NETs) have been reported. In this study, we sought to determine the prevalence and characteristics of NET in patients with CS.

METHODS

Mayo Clinic electronic medical records were searched for patients with CS. Data on demographics, CS diagnosis, family history, genetic testing, and NET diagnosis were extracted.

RESULTS

A total of 26 patients with CS were identified with 3 (11.5%) of them having an additional diagnosis of NET. Three patients had a family history of NET (11.53%), and 7 patients had a family history of CS (26.9%). Of the 3 NET/CS patients, 2 had a confirmed primary NET from the presacral mass, with the third patient demonstrating focal uptake on the somatostatin receptor imaging within the presacral. Two patients received octreotide, followed by peptide receptor radionuclide therapy. The other patient was not treated because of complete resection of presacral mass and is currently undergoing surveillance scans.

CONCLUSIONS

In our patients with CS, the prevalence of NET is 11.53%. The coexistence of 2 rare conditions, CS and presacral NET, suggests that there may be an etiological connection.

Novel MNX1 mutations and genotype-phenotype analysis of patients with Currarino syndrome

Background

Currarino syndrome (CS) is a specific complex of congenital caudal anomalies, including anorectal malformations, presacral mass and sacral anomalies. Mutations in the MNX1 gene are closely related to CS and occur in almost all familial cases and less than half of sporadic patients. We investigated the spectrum of MNX1 pathogenic variants and associated clinical features in Chinese patients with CS.

Results

Seventeen index patients from 16 families were recruited from 2015 to 2018. All patients were diagnosed with CS and treated at the Capital Institute of Pediatrics Affiliated Children’s Hospital. Genetic testing was applied to identify mutations in CS patients and their relatives by whole-exome sequencing and Sanger sequencing. Functional verification was performed for a recurrent noncanonical splice site variant in MNX1 with a minigene splicing assay. In 17 CS patients, 14 were complete CS and 3 were mild CS. Nine variants in MNX1 were identified in 11 patients, and these included two frameshift mutations (p.Leu223Leufs*61, p.X402Serfs*70), four nonsense mutations (p.Gly42X, p.Cys88X, p.Gln24X, p.Cys241X), one missense mutation (p.Trp288Leu), one splice region variant (c.691 + 3G > T) and one polyalanine polymorphism (p.Ala135insAlaAla). Seven of these nine variants have never been reported. Pathogenic MNX1 mutations were found in 100% (4/4) of familial and 46% (6/13) of sporadic patients.

Conclusion

Our study expanded the mutation spectrum of MNX1 and provided clinical and genetic analyses of seventeen CS patients from mainland China.

Laparoscopic-Assisted Anorectal Pull-Through for Currarino Syndrome

Objective: Currarino syndrome (CS) is characterized by the triad of sacral anomalies, presacral tumor, and anorectal malformation (ARM). This study evaluates the feasibility and outcomes of laparoscopic-assisted anorectal pull-through (LAARP) for CS. Materials and Methods: Children admitted for primary or redo repair of CS through LAARP between 2016 and 2019 were reviewed. The indication of redo included constipation with megarectosigmoid, residual presacral mass, anastomosis leak, and secondary fistula. ARM was corrected by excision of rectal stenosis, fistula, and its associated megarectosigmoid. This was followed by a complete surgical resection of the presacral tumor, with subsequent pull-through and anocolic anastomosis. This was done with a combined laparoscopic and transanal approach. The detailed surgical techniques, early postoperative complications, and mid-term functional outcomes were summarized. Results: Fourteen patients underwent LAARP for primary (N = 4) and redo (N = 10) repair of CS. Four of them had colostomy previously. Mean age at operation was 20.7 ± 13.9 months. Mean operative time was 120 ± 25 minutes. Median hospital stay was 8 days (range 7-9 days) postoperatively. None of the patients developed early postoperative complications such as anastomotic leaks, presacral abscesses, recurrent fistulas, and residual mass. Bowel function was assessed 1 year after LAARP in 10 patients. Mean follow-up time was 15.9 months. The frequency of bowel movements was 3.3 ± 1.5/day. Constipation occurred in 2 patients. Occasional soiling (<3 times/week) was reported in 4 patients and frequent soiling (>3 times/week) was in 1. Conclusion: LAARP for CS is safe and effective.

Currarino syndrome presenting as a cerebrospinal fluid leak from the dermal sinus tract: case report

Currarino syndrome is an autosomal dominant condition with variable expressivity and penetrance that is associated with several classic features: sacral dysgenesis, presacral mass, and/or anorectal anomalies. The authors present a unique case in which the patient's initial presentation was a CSF leak from a sinus tract. The sinus tract was identified and disconnected from the thecal sac, obliterating the anterior sacral meningocele. This case represents a unique scenario in which Currarino syndrome manifested as a CSF leak from a dermal sinus tract.

Congenital pelvic skeletal anomalies: Clinical and radiographic evaluation of newborns with gastrointestinal malformation

BACKGROUND

Congenital pelvic skeletal anomalies (CPSA) may appear as isolated defects or in association with other anomalies like congenital malformations of the digestive system (CMDS). Minor CPSA in non-syndromic patients are often overlooked. We aimed to assess the frequency of CPSA in newborns with CMDS to review the diagnostic approaches.

STUDY DESIGN

A retrospective review of medical records of 201 newborns who underwent X-rays for different neonatal indications was conducted. In 122 patients CMDS were diagnosed and classified according to the ICD-10 classification; 79 non-CMDS patients acted as controls. Pelvic skeletal segments were examined by X-rays.

RESULTS

Patients with CMDS, showed a higher risk of CPSA (Odds ratio 2.89; 95% CI 1.34 6.23) and other associated malformations in comparison to non-CMDS patients. Newborns with malformations of the large intestine have the highest risk of adjacent CPSA (48%), as it is a developmental defect originating from the same somite. In addition to skeletal agenesis/hypoplasia, we reported dysmorphic and bifid vertebras, trident ileum, and elongated neural arches.

CONCLUSIONS

The high incidence of CPSA in CMDS suggests performing a routine radiographic pelvic evaluation in cases of CMDS in order to identify complex phenotypes that could originate from the same developmental field.

Currarino syndrome and microcephaly due to a rare 7q36.2 microdeletion: a case report

Background

Currarino syndrome is a rare condition characterized by presacral mass, anorectal malformation and sacral dysgenesis.

Case presentation

We report the case of a child that presented chronic constipation, encopresis and mycrocephaly. The characteristics were initially compatible with a case of functional constipation and a therapy with polyethylene glycol was prescribed. After a year, because of poor response, a plain abdominal X-ray was performed, detecting sacrum abnormalities. Finally, a CGH-array analysis was performed and a form of Currarino Syndrome caused by a rare 7q36 microdeletion, was diagnosed.

Conclusion

Occult spinal dysraphism should be suspected in case of poor polyethylene glycol responder constipation, even when evident sacral abnormalities on the physical examination are not detected.