Sacral agenesis
From Wikipedia, the free encyclopedia
| Sacral agenesis | |
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| Classification and external resources | |
| DiseasesDB | 31157 |
Sacral agenesis (or hypoplasia of the sacrum) (also more commonly called caudal regression syndrome) is a little known and rather infrequent congenital condition of spinal deformity affecting the sacrum—the caudal partition of the spine. It occurs at a rate of approximately one per 25,000 live births.
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[edit] Etiology
The condition arises from some factor or set of factors present during approximately the 3rd week to 7th week of fetal development. Formation of the sacrum/lower back and corresponding nervous system is usually nearing completion by the 4th week of development. Due to abnormal gastrulation, the mesoderm migration is disturbed. This disturbance results in symptoms varying from minor lesions of the lower vertebrae to more severe symptoms such as complete fusion of the lower limbs. While the exact etiology is unknown, it has been speculated that the condition may be associated with certain dietary deficiencies including a lack or insufficient amounts of folic acid. The condition may also be associated with or resultant from maternal diabetes. Sacral agenesis syndrome (agenesis of the lumbar spine, sacrum, and coccyx, and hypoplasia of the lower extremities) is a well-established congenital anomaly associated with maternal diabetes mellitus.
The dominant inherited sacral agenesis (also referred to as Currarino syndrome) is very often correlated with a mutation in the Hb9 (also called HlxB9) gene (shown by Sally Ann Lynch, 1995, Nature Genetics).
[edit] Associations
VATER- vertebral defects, anal atresia, tracheoesophageal fistula, and renal defects.
[edit] Prognosis
There are four levels (or "types") of malformation. The least severe indicates partial formation (unilateral) of the sacrum. The second level indicates a bilateral (uniform) deformation. And the most severe types involve a total absence of the sacrum.
Depending on the type of sacral agenesis—bowel or urinary bladder deficiencies may be present. A permanent colostomy may be necessary in the case of imperforate anus. Incontinence may also require some type of continence control system (e.g. self-catheterization) be utilized. Occasionally if deformities of the knees, legs or feet would prove unresponsive to corrective action—amputation at the knee may be proposed.
Before more comprehensive medical treatment was available, full amputation of the legs at the hip was often performed.
[edit] See also
[edit] References
- orthoped/618 at eMedicine
- vii/s/sacral_agenesis article at GE's Medcyclopaedia
- Sonek JD, Gabbe SG, Landon MB, Stempel LE, Foley MR, Shubert-Moell K., Antenatal diagnosis of sacral agenesis syndrome in a pregnancy complicated by diabetes mellitus. Am J Obstet Gynecol. 1990 Mar;162(3):806-8.
