News Release

Tuesday, May 26, 2009

Birth Defects of the Kidney Explained in New NIDDK Fact Sheets

Kidney disorders can develop before a child is born. Two new fact sheets from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health, explain two of these disorders: kidney dysplasia and medullary sponge kidney.

Kidney dysplasia, which occurs during fetal development, is a condition in which the internal structures of one or both of the baby’s kidneys fail to develop normally. Dysplasia usually occurs in only one kidney. Babies with just one working kidney can grow and develop normally with few health problems. However, fetuses with dysplasia in both kidneys may not survive pregnancy and, if they do, they will need dialysis or a kidney transplant early in life.

Medullary sponge kidney (MSK) is a birth defect in which cysts form in the inner part of the kidney — or medulla — keeping urine from flowing freely through the kidney’s inner tubules. While many people with MSK have no symptoms, problems such as blood in the urine, kidney stones and urinary tract infections could develop, but usually much later in life — around ages 30 to 40. MSK rarely leads to more serious problems, such as total kidney failure.

The fact sheets, "Kidney Dysplasia" and "Medullary Sponge Kidney," explain signs and symptoms as well as diagnosis and treatment. Links to the publications are available in the A to Z list of topics and titles at

To order copies of the fact sheets, go to, click on "Order Publications," then on "Kidney and Urologic Diseases Materials." The NIDDK produces fact sheets and booklets about a multitude of issues related to kidney and urologic functions.

Publications also can be ordered by calling the NIDDK’s National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) at 1-800-891-5390 or writing to the NKUDIC at 3 Information Way, Bethesda, MD 20892–3580.

The NKUDIC was created in 1987 to increase knowledge and understanding about diseases of the kidneys and urologic system among people with these conditions and their families, health care professionals and the general public.

The NIDDK, part of NIH, conducts and supports basic and clinical research and research training on some of the most common, severe and disabling conditions affecting Americans. The Institute's research interests include: diabetes and other endocrine and metabolic diseases; digestive diseases, nutrition, and obesity; and kidney, urologic and hematologic diseases. For more information, visit

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

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