Currarino syndrome

Currarino syndrome (also known as Currarino triad or hereditary sacral agenesis) is a rare congenital disorder characterized by a classic triad of anomalies: sacral bone defects (typically a sickle-shaped or "scimitar" sacrum), anorectal malformations (most commonly anorectal stenosis), and a presacral mass. The presacral mass may be an anterior sacral meningocele, a teratoma (mature or immature), or a combination of both (termed a hamartoma). The condition is caused by mutations in the MNX1 gene (formerly HLXB9) located on chromosome 7q36, which plays a critical role in embryonic development of the caudal region. Not all affected individuals present with the complete triad; some may have only one or two features, and the clinical expression is highly variable even within the same family. The syndrome primarily affects the skeletal, nervous, and gastrointestinal systems. Chronic constipation is the most common presenting symptom and may be the only clinical manifestation in mildly affected individuals. More severe cases can present in the neonatal period with bowel obstruction, meningitis (due to infection of the meningocele), or complications from the presacral mass. Tethered spinal cord and neurogenic bladder may also occur. Women with undiagnosed Currarino syndrome may experience obstetric complications. The presacral teratoma carries a small risk of malignant transformation, making early diagnosis and surveillance important. Diagnosis is established through imaging studies including pelvic X-ray, MRI of the spine and pelvis, and genetic testing for MNX1 mutations. Treatment is primarily surgical and may include correction of the anorectal malformation, excision of the presacral mass, and repair of the anterior meningocele. Surgical intervention is generally recommended even in asymptomatic patients to prevent complications such as infection or malignant transformation. Long-term follow-up is essential, particularly for bowel and bladder function. Genetic counseling is recommended for affected families given the autosomal dominant inheritance pattern with variable expressivity and incomplete penetrance.

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