Inclusion cell (I-cell) disease is a very rare genetic disorder that can cause a number of congenital defects and early developmental problems. Faulty genes impair the function of lysosomes, cell components that are essential for disposing waste materials. Without working lysosomes, waste builds up inside cells and disrupts other vital processes. Most children with I-cell disease suffer from malformed bones and muscles, short stature, motor movement problems, and mental retardation. There is no cure for the disorder, and treatment efforts are primarily focused on trying to improve the quality of life for young patients.
I-cell disease is inherited in an autosomal recessive pattern. In order for a child to develop the condition, both of his or her parents must possess mutated copies of the gene responsible for lysosomal enzyme production. Dysfunctional or missing enzymes prevent lysosomes from breaking down waste and expelling it from cellular bodies. As a consequence, certain types of cells do not develop and function correctly. The bones, muscles, and connective tissues are affected the most severely in I-cell disease.
Most cases of I-cell disease cause physical defects that are immediately noticeable at birth. Infants typically have high foreheads, flattened noses, and large, protruding gums. Bone development is significantly impaired, leading to stiff joints, crooked spines and deformities in the hands and feet. Young children with the disorder are often very short and have little or no muscle tone. There may be additional deformities in the heart and lungs that can lead to life-threatening complications.
I-cell disease causes major developmental delays in the majority of cases. In addition to physical problems, children are often severely mentally impaired. They may not be able to learn language, develop good judgment skills, or control their emotions. Patients usually need to be attended to around the clock for their entire lives; parents or caregivers are responsible for feeding, dressing, and bathing them.
Doctors can usually diagnose I-cell disease based on physical exams and genetic blood testing. There is no known cure for the disease, and medications usually have little or no effect on improving symptoms. Physical therapy and surgical correction of major bone and organ deformities may be able to help extend patients' lives. In most cases, however, complications of the disease lead to mortality before the age of ten. Ongoing genetic research hopes to uncover more facts about the disease and develop better treatment strategies in the near future.