Medullary cystic kidney disease (MCKD) is very similar to the childhood disease juvenile nephronopthesis (NPH). Both lead to scarring of the kidney and formation of fluid-filled cavities in the deeper parts of the kidney (medullary cysts). However, NPH occurs in young children and is usually due to autosomal recessive inheritance. MCKD occurs in older patients and is transmitted in an autosomal dominant pattern. In these conditions, the kidneys don't concentrate the urine enough, leading to excessive urine production and loss of sodium. Salt supplementation may be required. Additional kidney problems follow. Most MCKD patients reach end-stage kidney disease between the ages of 30 and 50. NPH patients are about 4 years of age when it begins. NPH may be associated with non-kidney features (like abnormalities in the eyes), while MCKD is limited to the kidneys only.
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