Currarino syndrome

Overview

Currarino syndrome is a rare congenital disorder defined by a classic triad of anomalies: partial sacral agenesis (missing or malformed lower spine), a presacral mass (such as a teratoma, meningocele, or anterior meningocele), and anorectal malformations (e.g., imperforate anus or anal stenosis). First described by Guido Currarino in 1981, the syndrome varies in severity but often presents in childhood. Early diagnosis and coordinated care are essential to prevent serious complications, such as infection, bowel obstruction, or neurological deficits.

Causes

Currarino syndrome is most commonly caused by mutations in the MNX1 gene (formerly HLXB9) located on chromosome 7q36. This gene is important for spinal cord and hindgut development. The syndrome follows an autosomal dominant inheritance pattern, meaning a person only needs one copy of the altered gene from an affected parent to inherit the disorder. However, spontaneous (de novo) mutations can also occur, especially in cases with no family history.

Symptoms

Symptoms of Currarino syndrome can range from mild to severe and may vary depending on the specific combination of anomalies. Common features include:

• Anorectal malformations: Imperforate anus, anal stenosis, or anteriorly displaced anus, often leading to chronic constipation

• Presacral mass: May be asymptomatic or cause symptoms such as pain, infection, or pressure on surrounding organs

• Sacral anomalies: Partial absence of the sacrum seen on imaging, often described as a "scimitar sacrum"

• Constipation: One of the most frequent presenting symptoms, often resistant to standard treatments

• Urinary issues: Such as incontinence, recurrent infections, or neurogenic bladder

• Neurological symptoms: If a tethered cord or meningocele compresses neural structures

Diagnosis

Diagnosis of Currarino syndrome typically involves a combination of clinical examination, imaging studies, and genetic testing. Steps may include:

• Pelvic and spinal X-rays: To detect sacral agenesis or bony abnormalities

• Pelvic MRI: The most accurate imaging method for identifying a presacral mass and associated spinal anomalies

• Ultrasound: Used in infants to evaluate pelvic structures and masses

• Genetic testing: To confirm MNX1 mutations and assist with family screening

• Colorectal and urological evaluation: For anorectal and urinary tract malformations

In many cases, the syndrome is diagnosed after investigation of chronic constipation in childhood or after discovery of a presacral mass during imaging for another reason.

Treatment

Treatment of Currarino syndrome is multidisciplinary and depends on the type and severity of anomalies. Management may involve:

• Surgical correction: For anorectal malformations (e.g., posterior sagittal anorectoplasty)

• Excision of presacral mass: To prevent complications such as infection, compression, or malignant transformation

• Neurosurgical intervention: If a tethered spinal cord or meningocele is present

• Constipation management: Laxatives, bowel training, or surgical interventions in resistant cases

• Urological care: Catheterization or surgical management for bladder dysfunction

• Genetic counseling: For families, particularly when MNX1 mutations are confirmed

Prognosis

The prognosis for individuals with Currarino syndrome is generally favorable with early diagnosis and appropriate treatment. Most patients can achieve good bowel and urinary control, especially when surgery is performed early. However, untreated or misdiagnosed cases may experience chronic complications such as severe constipation, infections, or neurological impairment. Lifelong monitoring is often recommended due to the risk of recurrence or delayed complications, particularly in patients with presacral masses or spinal cord involvement.