Ribosomes are the structures inside of a cell in which proteins are made. It was once thought that any mutations in the ribosomes would be deadly, but scientists discovered otherwise. In August of 2008, the National Institute of Diabetes and Digestive and Kidney Diseases, the Centers for Disease Control and Prevention and the National Heart, Lung and Blood Institute held a workshop where experts presented the latest information about ribosomal diseases.
This is an inherited disease, which affects approximately five infants out of every 1 million, according to Neal Young, M.D., of the National Heart, Lung, and Blood Institute in "Williams Hematology." Children have anemia because the bone marrow is not making enough red blood cells. Approximately 33 percent may have physical abnormalities, including wide-set eyes, low-set ears, a webbed neck and short stature. Some children have heart and skeletal abnormalities as well.
According to the National Institutes of Health, or the NIH, this disease is due to mutations in seven genes. Some of the mutated genes give instructions to the cell on how to make ribosomal proteins, while others help the ribosomes make proteins.
Cartilage Hair Hypoplasia
Cartilage hair hypoplasia is a hereditary disease. Children have thin, light-colored hair that is hypoplastic, or underdeveloped. They have short limbs and a short stature. The children are not only anemic, but may have thrombocytopenia and leukopenia, writes Hans Ochs, M.D., Chair of Pediatric Immunology Research at Seattle Children's Research Hospital in "Williams Hematology."
Thrombocytopenia is an abnormally low number of thrombocytes, or platelets. Children with leukopenia have a very low number of white blood cells, and since these cells fight infection, they may be susceptible to contracting various infections. Some have an impaired immune system and develop cancers. The NIH reports that this disease is due to a mutation in a gene that helps make an enzyme. These are proteins that speed up processes, and this enzyme builds ribosomal RNA.
Approximately one child in every 100,000 is born with this ribosomal disorder, states George Segel, M.D., of the Department of Pediatrics at the University of Rochester Medical Center in "Williams Hematology." Most have problems with their pancreas. This leads to steatorrhea, or a fatty bowel movement, because the child's pancreas does not release enough enzymes to digest fats. These children have neutropenia, or a low number of the neutrophil type of white blood cell, which gives them reoccurring infections. About 50 percent are anemic and some have thrombocytopenia.
Most children are short and have skeletal abnormalities like dental cavities and webbed fingers. According to the NIH, 90 percent of those with Shwachman-Diamond syndrome have a mutation in a gene that may participate in making ribosomes.
This inherited disease is more common in males than females and is seen in one child out of every 1 million, writes Dr. Segal in "Williams Hematology." The symptoms start when a child is approximately 5 years old. They may have tan or gray spots on their skin, nail abnormalities, and hair loss from their eyebrows, eyelashes and scalp. Later on as children or as young adults, they usually develop aplastic aneia, where the bone marrow does not make enough red blood cells, white blood cells or platelets. The disease is caused by a gene needed to make ribosomes.
- National Institute of Diabetes and Digestive and Kidney Disease: Workshop on Ribosomes and Their Role in Disease
- National Institutes of Health: Cartilage-hair hypoplasia
- National Institutes of Health: Diamond-Blackfan anemia
- National Institutes of Health: Shwachman-Diamond syndrome
- "Williams Hematology"; Marshall Lichtman, M.D., Thomas Kipps, M.D. et al.; 2010