Enzymes are special types of proteins required to break down food molecules into fuel during metabolism, the process by which the body gets energy for normal growth and development. Enzyme deficiencies, or the absence of these enzymes, are inherited defects that result in a number of life-changing or life-threatening conditions:
The mucopolysaccharidoses are a group of inherited diseases in which a defective or missing enzyme causes complex sugar molecules to accumulate in cells. As a result, progressive damage is done to the heart, bones, joints, respiratory system and central nervous system. While the disease may not be apparent at birth, signs and symptoms develop with age as more cells become damaged. It is estimated that one in every 25,000 babies born in the United States has some form of MPS.
Lysosomal storage disorders are a group of approximately fifty inherited disorders that occur when a missing enzyme results in the body’s inability to recycle cellular waste. The severity of the disorder depends on the type and amount of cellular debris that accumulates, but almost all disorders are progressive. Many of these children die in infancy or early childhood. It is estimated that one in every 5,000 babies born in the United States has some form of an LSD. Affected individuals often have mental retardation, cloudy corneas, short stature, stiff joints, incontinence, speech and hearing impairment, chronic runny nose, hernia, heart disease, hyperactivity, depression, pain and a dramatically shortened life span.
Nieman-Pick Disease refers to a group of inherited metabolic disorders known as lipid storage disorders. Patients diagnosed with these disorders lack a critical enzyme necessary to metabolize fatty substances in the body called lipids. As a result, harmful quantities of lipids accumulate in the spleen, liver, lungs, bone marrow and brain.
Symptoms may include lack of muscle coordination, brain degeneration, learning problems, loss of muscle tone, increased sensitivity to touch, spasticity, feeding and swallowing difficulties, slurred speech and an enlarged liver and spleen. The most common type, Type A, occurs in infants. Children with this type rarely live beyond 18 months. Type B involves an enlarged liver and spleen, which usually occurs in the pre-teen years, but the brain is not affected. Types C and D may appear early in life or develop later in the teens. These individuals may have only moderate enlargement of the spleen and liver, but brain damage may be extensive and cause an inability to look up and down, difficulty in walking and swallowing and progressive loss of vision and hearing. Type D usually occurs in people with an ancestral background in Nova Scotia.
The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National Institutes of Health (NIH), conducts research on Niemann-Pick and a number of these other rare childhood diseases in laboratories at the NIH. They also support additional research through grants to major medical institutions across the country.