Mucolipidosis type I (ML I) is an inherited lysosomal storage disease that results from a deficiency of the enzyme alpha-N -acetyl neuraminidase (sialidase). The lack of this enzyme results in an abnormal accumulation of complex carbohydrates known as mucopolysaccharides, and of fatty substances known as mucolipids. Both of these substances accumulate in bodily tissues. Presentation
Symptoms of ML I are either present at birth or develop within the first year of life. In many infants with ML I, excessive swelling throughout the body is noted at birth. These infants are often born with coarse facial features, such as a flat nasal bridge, puffy eyelids, enlargement of the gums, and excessive tongue size (macroglossia). Many infants with ML I are also born with skeletal malformations such as hip dislocation. Infants often develop sudden involuntary muscle contractions (called myoclonus) and have red spots in their eyes (cherry red spots). They are often unable to coordinate voluntary movement (called ataxia). Tremors, impaired vision, and seizures also occur in children with ML I. Tests reveal abnormal enlargement of the liver (hepatomegaly) and spleen (splenomegaly) and extreme abdominal swelling. Infants with ML I generally lack muscle tone (hypotonia) and have mental retardation that is either initially or progressively severe. Many patients suffer from failure to thrive and from recurrent respiratory infections. Most infants with ML I die before the age of 1 year. Related conditions
Other diseases that result from a deficiency in the sialidase enzyme are categorized in a broader group known as sialidoses.
One effect of aging and disc degeneration is that the nucleus pulposus begins to dehydrate and the concentration of proteoglycans in the matrix decreases, thus limiting the ability of the disc to absorb shock. This general shrinking of disc size is partially responsible for the common decrease in height as humans age. The anulus fibrosus also becomes weaker with age and has an increased risk of tearing. In addition, the cartilage endplates begin thinning, fissures begin to form, and there is sclerosis of the subchondral bone. Since the fissures are formed in the anulus fibrosus due to osteo-arthritic bones or degeneration in general, the inner nucleus pulposus can seep out and put pressure on any number of vertebral nerves. A herniated disc can cause mild to severe pain such as sciatica and treatment for herniated discs range from physical therapy to surgery. (see also: Intervertebral disc arthroplasty) Other degeneration of the vertebral column includes diffuse idiopathic skeletal hyperostosis (DISH) which is the calcification or ossification of the ligaments surrounding the vertebrae. This degeneration causes stiffness and sometimes even curvature in the lumbar and thoraco-lumbar spinal region. Burgeoning evidence suggests that long-term running may mitigate age-related degeneration within lumbar intervertebral discs

Scoliosis
While this may not cause pain in some people, in others it may cause chronic pain. Other spinal disorders can affect the morphology of intervertebral discs. For example, patients with scoliosis commonly have calcium deposits (ectopic calcification) in the cartilage endplate and sometimes in the disc itself.