Caudal regression syndrome

Caudal regression syndrome (CRS), also known as sacral agenesis or caudal dysplasia, is a rare congenital disorder characterized by abnormal development of the lower (caudal) end of the spine and spinal cord. The condition encompasses a spectrum of malformations ranging from partial absence of the tailbone (coccyx) to complete absence of the sacral and lumbar vertebrae. CRS affects multiple body systems, including the musculoskeletal, genitourinary, gastrointestinal, and nervous systems. Key clinical features include varying degrees of sacral and lumbar vertebral agenesis, lower limb abnormalities (including hypoplasia, contractures, or fusion of the legs known as sirenomelia in the most severe cases), neurogenic bladder, bowel dysfunction (including anorectal malformations and fecal incontinence), and renal anomalies. Motor and sensory deficits in the lower extremities are common and depend on the level of spinal involvement. The exact cause of caudal regression syndrome is not fully understood, but it is considered multifactorial. A strong association exists with maternal diabetes mellitus, particularly pregestational insulin-dependent diabetes, which increases the risk significantly. Most cases occur sporadically. Rare familial cases have been reported, and mutations in the VANGL1 gene and HLXB9 (MNX1) gene have been identified in some patients, particularly those with hereditary sacral agenesis (Currarino syndrome is a related but distinct entity). The condition is thought to result from disruption of normal mesoderm development during the third to seventh weeks of gestation. There is no cure for caudal regression syndrome, and treatment is supportive and multidisciplinary. Management typically involves orthopedic interventions for spinal and lower limb deformities (including bracing, prosthetics, or surgical correction), urological management for neurogenic bladder (such as clean intermittent catheterization), bowel management programs for fecal incontinence, and neurosurgical evaluation for associated spinal cord anomalies such as tethered cord. Physical therapy and rehabilitation play important roles in maximizing mobility and independence. Long-term outcomes vary widely depending on the severity of vertebral and neurological involvement, with many individuals achieving functional independence with appropriate support.

Common questions about Caudal regression syndrome