Lysosomal storage disease

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at November 3, 2016
StartDiseasesLysosomal storage disease

Lysosomes are organelles that contain enzymes which metabolize (break down) excess sugars and lipids into substances that the body can use. Inherited deficiencies of any lysosomal components, including lysosomal enzymes, are referred to as lysosomal storage disorders or lysosomal storage disease.

Contents

Definition & Facts

Lysosomal storage disorders are health condition that results in the accumulation of undigested or partially digested sugars and lipids (fats) in different parts of the body. The buildup of these substances ultimately causes damage to body cells and organs and can lead to death.

There are over 50 lysosomal storage disorder types. The age of onset and clinical manifestations differ significantly among patients with different types of these disorders, and there is a remarkable phenotypic heterogeneity between family members with identical mutations. The diseases are classified by the particular enzymes involved. Some of these diseases include:

Symptoms & Complaints

Symptoms of lysosomal disorders can be mild and, sometimes, severe. They appear shortly after birth and are progressive over a period. The progression rate, organs affected, and the severity of the symptoms vary within each disorder type. Some of the most common symptoms include the following:

While these symptoms are most commonly related with lysosomal storage disorders, other health conditions can cause them as well. Individuals who have one or many of these symptoms should see their doctor for diagnosis and testing.

Causes

Genetic mutations are responsible for lysosomal storage disorders, and most of these diseases are inherited in an automatic recessive manner.

Diagnosis & Tests

Doctors can diagnose diagnosis lysosomal storage disease during pregnancy (prenatal diagnosis), in newborns, and children. Medical professionals will assess patients for a variety of symptoms.

Echocardiograms may be conducted to assess heart abnormalities. Abdominal ultrasonography may be done to assess the presence of an enlarged spleen and/or liver. Neurological examinations may be done to detect intellectual disabilities/cognitive impairments and epilepsy. Eye examinations may be conducted to detect abnormalities of the eye (such as cherry-red spots characteristic of Tay-Sachs disease).

Blood tests and clinical urine tests can be done to detect abnormal levels of enzymes. Magnetic resonance imaging (MRI) scans of the brain can be used to detect brain abnormalities. Tissue biopsy is the removal of sample tissues from the body of the patient and the examination of the sample under a microscope.

Treatment & Therapy

Research is underway to find the cure for lysosomal storage disorders. However, there are therapies that significantly enhance the quality of life for those affected by this health problem. Bone marrow transplantation (BMT) can be effective in stimulating the body to create new cells that contain the deficient enzymes. Pyrimethamine is a medication that may be able to increase the amount of the missing enzyme associated with Tay-Sachs disease.

Substrate synthesis inhibition therapy can help remove substances from the body that accumulate due to the deficiency of the enzyme that metabolizes those substances. Examples include miglustat and Eliglustat which are used to treat Gaucher's disease. Enzyme replacement therapy (ERT) replaces the enzymes the body is deficient in. These are usually administered intravenously.

Physical therapy, occupational therapy, special education, and speech therapy may all be utilized to address various symptoms of these disorders. Dialysis and surgery may also be recommended depending on the manifestation of symptoms associated with these disorders.

Prevention & Prophylaxis

Because lysosomal storage disorders are genetic and inherited, they cannot be prevented. Prospective parents may choose to undergo genetic counseling in order to assess the risk that their offspring may inherit a disorder. Those with a family history of these disorders in particular may opt for genetic counseling.