There are different types of inherited disorders Inheritance of Single-Gene Disorders Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are made of a very long strand... read more . In many hereditary metabolic disorders, both parents of the affected child carry a copy of the abnormal gene. Because usually two copies of the abnormal gene are necessary for the disorder to occur, usually neither parent has the disorder. Some hereditary metabolic disorders are X-linked X-Linked Recessive Disorders Genes are segments of deoxyribonucleic acid (DNA) that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are made of a very long strand... read more , which means only one copy of the abnormal gene can cause the disorder in boys. (See also Overview of Hereditary Metabolic Disorders Overview of Hereditary Metabolic Disorders Hereditary metabolic disorders are inherited genetic conditions that cause metabolism problems. Heredity is the passing of genes from one generation to the next. Children inherit their parents'... read more .)
Lipidoses occur when the body lacks one of the enzymes that help the body break down (metabolize) and process fats Fats Carbohydrates, proteins, and fats supply 90% of the dry weight of the diet and 100% of its energy. All three provide energy (measured in calories), but the amount of energy in 1 gram (1/28 ounce)... read more (lipids). This can lead to the buildup of specific fatty substances that normally would have been broken down by the enzymes. Over time, accumulations of these substances can be harmful to many organs of the body.
In cholesteryl ester storage disease and Wolman disease, cholesterol and triglycerides, which are important fats in the blood, accumulate in tissues. The enzyme needed to break down cholesterol and triglycerides, called lysosomal acid lipase, does not work correctly.
Wolman disease is the more severe disease. This disease occurs in the first few weeks of life. Infants feed poorly, vomit, and have an enlarged spleen and liver. Calcium deposits in the adrenal glands cause them to harden. Bowel movements contain excess fat, which results in oily, unusually foul-smelling, bulky stools (steatorrhea). Infants with Wolman disease usually die by 6 months of age if untreated.
Cholesteryl ester storage disease is less severe than Wolman disease and may not occur until later in life, even adulthood, at which time people may have an enlarged liver and spleen. People may develop premature hardening of the arteries (atherosclerosis Atherosclerosis Atherosclerosis is a condition in which patchy deposits of fatty material (atheromas or atherosclerotic plaques) develop in the walls of medium-sized and large arteries, leading to reduced or... read more ), which is often severe.
Before birth, cholesteryl ester storage disease and Wolman disease can be diagnosed in the fetus by chorionic villus sampling Chorionic Villus Sampling Prenatal diagnostic testing involves testing the fetus before birth (prenatally) to determine whether the fetus has certain abnormalities, including certain hereditary or spontaneous genetic... read more .
After birth, doctors measure levels of lysosomal acid lipase in a biopsy sample of the liver or other tissues (removal of a tissue specimen for examination).
Genetic testing Genetic Screening Genetic screening is used to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder. Hereditary genetic disorders are disorders of chromosomes or... read more , which is used to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder, is also available.