Spondylolysis is a defect or stress fracture in the pars interarticularis of the vertebral arch. The vast majority of cases occur in the lower lumbar vertebrae (L5), but spondylolysis may also occur in the cervical vertebrae. Signs and symptoms
In majority of cases, spondylolysis presents asymptomatically which can make diagnosis both difficult and incidental. When a patient does present with symptoms, there are general signs and symptoms a clinician will look for:

Clinical signs:Pain on completion of the stork test (placed in hyperextension and rotation)
Excessive lordotic posture
Unilateral tenderness on palpation
Visible on diagnostic imaging (Scottie dog fracture)
Symptoms:Unilateral low back pain
Pain that radiates into the buttocks or legs
Onset of pain can be acute or gradual
Pain that can restrict daily activities
Pain that worsens after strenuous activity
Pain aggravated with lumbar hyperextension
Difficulty in movement in spinal cord

Cause
The cause of spondylolysis remains unknown, however many factors are thought to contribute to its development. The condition is present in up to 6% of the population, majority of which usually present asymptomatically. Research supports that there are hereditary and acquired risk factors that can make one more susceptible to the defect. The disorder is generally more prevalent in males compared to females, and tends to occur earlier in males due to their involvement in more strenuous activities at a younger age. In a young athlete, the spine is still growing which means there are many ossification centers, leaving points of weakness in the spine. This leaves young athletes at increased risk, particularly when involved in repetitive hyperextension and rotation across the lumbar spine.
Neonatal adrenoleukodystrophy is an inborn error of peroxisome biogenesis. It is part of the Zellweger spectrum. It has been linked with multiple genes (at least five) associated with peroxisome biogenesis, and has an autosomal recessive pattern of inheritance. References


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