Currarino triad

Other Names: Currarino syndrome; Partial sacral agenesis with intact first sacral vertebra, presacral mass and anorectal malformation

Currarino triad or syndrome is an autosomal dominant hereditary condition which is characterized by the triad of sacral agenesis abnormalities (abnormally developed lower spine), anorectal malformation (most commonly in the form of anorectal stenosis) and presacral mass consisting of a teratoma, anterior sacral meningocele or both. However only 1 out of 5 cases of Currarino triad has all three abnormalities present. Currarino triad is considered a spectrum disorder with a wide variation in severity. Up to one-third of the patients are asymptomatic and may only be diagnosed during adulthood only on X-rays and ultrasound examinations that are performed for different reasons.

Epidemiology

Currarino triad (syndrome) is an extremely rare condition, with an incidence of approximately 1 in 100,000,1 and only about 300 cases reported worldwide so far.

Cause

Currarino triad is caused by mutations in the MNX1 gene in nearly all familial and 30% of sporadic cases. These mutations in the gene are called loss of function mutations because the gene can no longer produce working (functional) protein. Less frequently, a complex phenotype of Currarino triad can be caused by microdeletions of 7q containing MNX1 (the long arm of chromosome 7 is missing a small piece of DNA which includes MNX1 and other genes).

Inheritance

Autosomal dominant pattern, a 50/50 chance.

Currarino triad is inherited in an autosomal dominant manner. This means that having a change (mutation) in only one copy of the MNX1 gene in each cell is enough to cause features of the condition. In some cases, an affected person inherits the mutated gene from an affected parent. In other cases, the mutation occurs for the first time in a person with no family history of the condition. This is called a de novo mutation.

When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation. A significant interfamilial (between different families) and intrafamilial (within the same family) variability in expression has been found without any definite correlation to the genetic mutations. This means in one family, a parent might only have one very mild feature of Currarino triad while one of their children might have severe forms of all three features and yet another child might have a mild form of one feature and a severe form of another.

Signs and symptoms

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Aplasia/Hypoplasia of the sacrum(Absent/small sacrum)
• Sacrococcygeal teratoma

5%-29% of people have these symptoms

• Abnormal intestine morphology(Abnormality of the intestine)
• Arteriovenous malformation
• Bifid scrotum(Cleft of scrotum)
• Hypoplasia of penis(Underdeveloped penis)
• Hypospadias
• Lower limb asymmetry(Left and right leg differ in length or width)
• Male pseudohermaphroditism
• Vesicoureteral reflux

1%-4% of people have these symptoms

• Bifid sacrum
• Hemisacrum

Diagnosis

Diagnosis of Currarino syndrome is usually clinical, detecting all three elements of the triad. However, genetic testing is often used as the confirmation of diagnosis and genetic analysis of patient's family members.

Treatment

Surgery of an anterior myelomeningocele is not necessarily indicated, only in the rare case in which the space-occupying aspect is expected to cause constipation or problems during pregnancy or delivery. Fistulas between the spinal canal and colon have to be operated on directly. A posterior procedure via lumbar and sacral partial laminectomy-laminoplasty and transdural ligation of the neck of the meningocele for anterior sacral meningoceles, or alternatively, tumor excision for other types of presacral lesions.

Endoscopic or endoscope-assisted surgery via a posterior sacral route can be feasible for treatment of some of the patients with anterior sacral meningocele. Anterior meningocele pouch associated with Currarino syndrome will regresses over time following transdural ligation of its neck.

The meningocele was removed using an anterior abdominal approach. A sigmoid resection was performed with rectal on-table antegrade lavage followed by closure of the rectal fistula, closure of the rectal stump, and proximal colostomy. Closure of the sacral deficit was carried out by suturing a strip of well-vascularized omentum and fibrin glue.

Prompt surgical management using an anterior approach, resection of the sac, closure of the sacral deficit, and fecal diversion resulted in a satisfactory outcome.

NIH genetic and rare disease info

• NIH info on Currarino triad

Currarino triad is a rare disease.

Currarino triad Resources
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