$Unique_ID{BRK03820} $Pretitle{} $Title{Hers Disease} $Subject{Hers Disease Glycogen Storage Disease VI Glycogenosis Type VI Hepatophosphorylase Deficiency Glycogenosis Liver Phosphorylase Deficiency Phosphorylase Deficiency Glycogen Storage Disease of Liver Andersen Disease Forbes Disease Glycogenosis Type VIII Von Gierke Disease } $Volume{} $Log{} Copyright (C) 1987, 1990, 1991 National Organization for Rare Disorders, Inc. 401: Hers Disease ** IMPORTANT ** It is possible the main title of the article (Hers Disease) is not the name you expected. Please check the SYNONYMS listing on the next page to find alternate names, disorder subdivisions, and related disorders covered by this article. Synonyms Glycogen Storage Disease VI Glycogenosis Type VI Hepatophosphorylase Deficiency Glycogenosis Liver Phosphorylase Deficiency Phosphorylase Deficiency Glycogen Storage Disease of Liver Information of the following diseases can be found in the Related Disorders section of this report: Andersen Disease Forbes Disease Glycogenosis Type VIII Von Gierke Disease General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Hers Disease is a hereditary glycogen storage disease which usually has milder symptoms than most other types of glycogen storage disorders. It is caused by a deficiency of the enzyme known as liver phosphorylase. Hers Disease is characterized by enlargement of the liver (hepatomegaly), moderately low blood sugar (hypoglycemia), elevated levels of acetone and other ketone bodies in the blood (ketosis), and moderate growth retardation. Symptoms are not always evident during childhood. Children are usually able to lead normal lives. In some cases symptoms may be severe. Symptoms Symptoms of Hers Disease may not be apparent during childhood. Mild to moderately low blood sugar can cause symptoms of faintness, weakness, hunger, and nervousness. Growth rate may be slowed, and enlargement of the liver may occur because of an excess accumulation of glycogen. Glycogen is the stored form of energy derived from carbohydrates. In many cases the body can adapt to low blood sugar levels and it is able to produce energy by other means. Therefore, symptoms may go unnoticed for long periods of time. Causes Hers Disease is a hereditary glycogen storage disorder inherited through autosomal recessive genes. The disorder is caused by a lack of the enzyme known as liver phosphorylase. Because of this enzyme deficiency, the stored form of energy derived from carbohydrates (glycogen) may accumulate in the liver and cause liver enlargement (hepatomegaly). Human traits including the classic genetic diseases, are the product of the interaction of two genes for that condition, one received from the father and one from the mother. In recessive disorders, the condition does not appear unless a person inherits the same defective gene from each parent. If one receives one normal gene and one gene for the disease, the person will be a carrier for the disease, but usually will show no symptoms. The risk of transmitting the disease to the children of a couple, both of whom are carriers for a recessive disorder, is twenty-five percent. Fifty percent of their children will be carriers, but healthy as described above. Twenty-five percent of their children will receive both normal genes, one from each parent and will be genetically normal. Affected Population All Glycogen Storage Diseases together affect less than 1 in 40,000 persons in the United States. Symptoms of Hers Disease are usually not noticed until adulthood although the disorder may present in childhood. Related Disorders Glycogen Storage Diseases are caused by inborn errors of metabolism in which the balance between stored energy (glycogen) and available energy (sugar or glucose) is disturbed. Too much glycogen tends to be stored in the liver and muscles and too little sugar becomes available in the blood. The following diseases are similar to Hers Disease. Comparisons may be useful for a differential diagnosis: Von Gierke Disease is a hereditary glycogen storage disease caused by an inborn lack of either the enzyme glucose-6-phosphatase or the enzyme glucose-6-phosphate translocase. These enzymes are needed to convert the main carbohydrate storage material (glycogen) into sugar (glucose) which the body uses for its energy needs. A deficiency of these enzymes causes deposits of excess glycogen in the liver and kidney cells. Forbes Disease (Glycogenosis III; Cori Disease) is another genetic glycogen storage disease. This disorder is caused by a lack of a debrancher enzyme (amylo-1,6-glucosidase). This enzyme deficiency causes excess amounts of glycogen to be deposited in the liver and muscles. The heart may be involved in some cases. Andersen Disease is a glycogen storage disease inherited through recessive genes. Symptoms of this disorder are caused by a lack of the brancher enzyme (alpha-1,4-glucan 6-glucosyltransferase). Andersen Disease is characterized by liver scarring (cirrhosis) which can lead to liver failure. Glycogen Storage Disease VIII is a sex-linked genetic disorder caused by a deficiency of the enzyme liver phosphorylase kinase. The disorder is characterized by slightly low blood sugar (hypoglycemia). Excess amounts of glycogen (the stored form of energy that comes from carbohydrates) are deposited in the liver, causing enlargement of the liver (hepatomegaly). For more information on the above disorders, choose "Gierke," "Andersen," Forbes," and "Glycogen Storage Disease VIII" as your search terms in the Rare Disease Database. Therapies: Standard Diagnosis of Hers Disease is based on a test for activity of the liver phosphorylase enzyme. A small fragment of liver tissue is removed (biopsy) and assayed for the activity of the enzyme. In persons with Hers Disease this enzyme activity will be deficient. Symptoms of Hers Disease are generally mild and the disorder usually requires no treatment other than avoidance of prolonged tasting and monitoring by a physician. Therapies: Investigational Dr. Y.T. Chen at Duke University Medical Center, at the request of the Glycogen Storage Disease Association, is collecting DNA from patients with Glycogen Storage Disease Type I to form a DNA bank for GSDI. Interested patients may contact the Glycogen Storage Diseases Association for further information. The address and phone number of the organization are listed in the Resources section of this report. This disease entry is based upon medical information available through February 1991. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Hers Disease, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Association for Glycogen Storage Diseases Box 896 Durant, IA 52747 (319) 785-6038 Research Trust for Metabolic Diseases in Children Golden Gates Lodge, Weston Rd. Crewe CW1 1XN, England Telephone: (0270) 250244 National Digestive Diseases Information Clearinghouse Box NDDIC Bethesda, MD 20892 (301) 468-6344 For information on genetics and genetic counseling referrals, please contact: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References THE MERCK MANUAL 15th ed: R. Berkow, et al: eds; Merck, Sharp & Dohme Research Laboratories, 1987. Pp. 2078. CECIL TEXTBOOK OF MEDICINE, 18th ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Eds.: W. B. Saunders Co., 1988. Pp. 425.