1.   Take the alpha one antitrypsin enzyme deficiency in the lung.

2.   Companies are delving into gene therapy, in which genes are introduced to the body to correct for an enzyme deficiency.

3.   Gaucher disease, caused by a hereditary enzyme deficiency, can be painful, debilitating and sometimes fatal.

4.   The enzyme deficiency appears to alter development of neurons in the brain.

5.   The disease involves an enzyme deficiency that causes the myelin sheath surrounding nerves to the brain to degenerate.

6.   While they do indeed develop symptoms similar to those caused by the enzyme deficiency, the reason for their symptoms is not a lack of lactase.

7.   The enzyme deficiency causes waste products to build up in body tissues, causing problems with vision, hearing, movement, skeletal development, and brain function.

8.   An enzyme deficiency provoked by a defective gene causes pycno, a rare disease that may have afflicted the French painter.