Currarino syndrome

Lore & Background

Currarino syndrome is defined by three core features: improper formation of the sacrum, a mass in the presacral space, and malformations of the anus or rectum. The most common presacral mass is anterior sacral meningocele, occurring in 60% of cases. Other possible masses include presacral teratoma and enteric cyst. The presacral teratoma characteristic of Currarino syndrome may be a distinct kind, though it is usually considered a variant of sacrococcygeal teratoma.

Reader's Guide

The significance of Currarino syndrome lies in its distinct genetic basis and the need for multidisciplinary management. In 2000, the first large series of cases was genetically screened, confirming that mutations in the HLXB9 homeobox gene are specifically causative for the syndrome, distinguishing it from other forms of sacral agenesis. Diagnosis is usually clinical, detecting all three elements of the triad, with genetic testing used for confirmation and family analysis. Treatment focuses on surgical management of the presacral mass and anorectal malformation. Surgery for anterior myelomeningocele is indicated only when it causes constipation or problems during pregnancy or delivery. Fistulas between the spinal canal and colon require direct surgical repair. Early diagnosis and multidisciplinary assessment allow for a single-stage surgical approach. The prognosis mainly depends on the degree of associated sacral dysplasia, and management is similar to that of anorectal malformation.

Did You Know?

• Anterior sacral meningocele is the most common presacral mass in Currarino syndrome, occurring in 60% of cases.
• The disorder is caused by a mutation in the HLXB9 homeobox gene and is inherited in an autosomal dominant pattern.
• In 2000, the first large series of Currarino cases was genetically screened, showing the HLXB9 gene is specifically causative for the syndrome.
• Surgery for an anterior myelomeningocele is only indicated when it causes constipation or problems during pregnancy or delivery.

The Defining Triad and Presacral Masses

Currarino syndrome is a rare inherited congenital condition affecting roughly one in every 100,000 individuals. At its core, the disorder is defined by a triad of findings: an improperly formed sacrum (the fused vertebrae at the rear of the pelvis), a mass occupying the presacral space, and structural abnormalities of the anus or rectum. The presacral mass component carries particular clinical weight. In the majority of affected patients—about sixty percent—the mass takes the form of an anterior sacral meningocele, a protrusion of meningeal tissue that can complicate surgical planning considerably. Other, less frequent masses include enteric cysts and presacral teratomas. While presacral teratomas are generally regarded as a variant of the more familiar sacrococcygeal teratoma, the specific teratoma seen in Currarino syndrome may in fact represent a distinct entity rather than a simple subtype. Understanding which mass is present is critical, because it shapes every subsequent decision in the patient's care pathway.

The HLXB9 Gene and a Landmark Discovery

The genetic architecture of Currarino syndrome follows an autosomal dominant pattern, meaning a single altered copy of the responsible gene is sufficient to produce the condition. That gene is HLXB9, a member of the homeobox family, and mutations within it are the specific cause of the syndrome. The definitive proof came in 2000, when researchers conducted the first large-scale genetic screening of a series of confirmed Currarino cases. The results, published in the American Journal of Human Genetics, demonstrated that HLXB9 mutations are specifically causative for Currarino syndrome and are not responsible for other, unrelated forms of sacral agenesis. This distinction was crucial: it separated Currarino from a broader category of sacral developmental defects and anchored the syndrome to a single, identifiable genetic mechanism. For families, the autosomal dominant inheritance pattern carries practical implications, as genetic analysis of relatives can identify carriers and inform reproductive counseling. The 2000 study effectively transformed Currarino from a descriptive clinical entity into a precisely defined genetic disorder.

Diagnosis and the Multidisciplinary Imperative

In most cases, Currarino syndrome is identified clinically by recognizing all three elements of the characteristic triad: the sacral anomaly, the presacral mass, and the anorectal malformation. However, genetic testing plays an increasingly important confirmatory role, both in solidifying the diagnosis for the individual patient and in extending the analysis to family members who may carry the HLXB9 mutation. Because the syndrome can present with variable severity and because the presacral mass may range from a meningocele to a teratoma, early and thorough evaluation is strongly recommended. This evaluation is inherently multidisciplinary, drawing on expertise from pediatric surgery, neurosurgery, genetics, and radiology to map the full extent of the structural abnormalities before any intervention is planned. The goal of this coordinated assessment is to ensure that the correct surgical strategy—potentially including neurosurgical components—can be executed in a single-stage approach rather than requiring multiple separate operations. Accurate preoperative mapping of the sacral dysplasia and the nature of the presacral mass is what makes that streamlined, single-stage management possible.

Surgical Management and Prognosis

Treatment of Currarino syndrome is closely aligned with the established surgical approach for anorectal malformations, and prognosis is largely governed by the degree of associated sacral dysplasia. Not every presacral mass demands operative intervention. An anterior myelomeningocele, for instance, is typically left in place unless its space-occupying effect is expected to produce chronic constipation or to create difficulties during pregnancy and delivery. In contrast, fistulous connections between the spinal canal and the colon represent a more urgent surgical priority and must be addressed directly. When surgery is indicated, the emphasis is on a well-planned, single-stage procedure that can incorporate neurosurgical techniques alongside the anorectal repair, provided the preoperative evaluation has been sufficiently detailed. The multidisciplinary team's role is to tailor the operative plan to the specific anatomy of each patient, recognizing that the spectrum of sacral and presacral involvement varies widely. Ultimately, the quality of the long-term outcome hinges on how thoroughly the sacral dysplasia is characterized and how precisely the surgical correction is matched to the individual's structural deficits.