MU Discovery Helps Explain How Children Develop Rare, Fatal Disease

One of 100,000 children is born with Menkes disease, a genetic disorder that affects the body’s ability to properly absorb copper from food and leads to neurodegeneration, seizures, impaired movement, stunted growth and, often, death before age 3. Now, a team of biochemistry researchers at the University of Missouri has published conclusive scientific evidence that the gene ATP7A is essential for the dietary absorption of the nutrient copper. Their work with laboratory mice also provides a greater understanding of how this gene impacts Menkes disease as scientists search for a treatment.

Humans cannot survive if their bodies are lacking the ATP7A gene, yet children can develop Menkes disease when the gene is mutated or missing. Previously, scientists did not have a good model to test the gene's function or develop an understanding of the underlying causes of the disease symptoms. In his new study, Michael Petris, associate professor of biochemistry, was able to modify mice so that they were missing the ATP7A gene in certain areas of the body, specifically the intestinal track where nutrient absorption takes place.

"These findings help us to understand where in the body the function of this gene is vital and how the loss of the gene in certain tissues can give rise to Menke’s disease," said Petris, who is a researcher in the Bond Life Sciences Center and holds an appointment in the Department of Nutrition and Exercise Physiology. "We want to continue to explore the underlying biology of Menke’s disease to determine where we should focus our research efforts in the future. If we know which organs or tissues are most responsible for transporting copper throughout the body, we can focus on making sure the gene is expressed in those areas. This disease is ideal for gene therapy down the road."

Petris found that young mice missing the ATP7A gene in their intestinal cells were unable to absorb copper from food, resulting in an overall copper deficiency that mimics symptoms of Menkes disease in children. Petris says it's vital to ensure that the developing newborns absorb enough copper during the neonatal period when the demand for the mineral is highest.

"Copper is a little-appreciated but essential trace mineral in all body tissues," Petris said. "Cells cannot properly use oxygen without copper; it helps in the formation of red blood cells, and it helps keep the blood vessels, nerves, skin, immune system and bones healthy. Normally, people absorb enough copper through their food. However, in the bodies of those with Menkes disease, copper begins to accumulate at abnormally low levels in the liver and brain and at higher than normal levels in the kidney and intestinal lining."

What is Menkes Disease? Menkes disease is caused by a defective gene named ATPTA that regulates the metabolism of copper in the body. The disease primarily affects male infants. Copper accumulates at abnormally low levels in the liver and brain, but at higher than normal levels in the kidney and intestinal lining. Affected infants may be born prematurely, but appear healthy at birth and develop normally for 6 to 8 weeks. Then symptoms begin, including floppy muscle tone, seizures, and failure to thrive. Menkes disease is also characterized by subnormal body temperature and strikingly peculiar hair, which is kinky, colorless or steel-colored, and breaks easily. There is often extensive neurodegeneration in the gray matter of the brain. Arteries in the brain may be twisted with frayed and split inner walls. This can lead to rupture or blockage of the arteries. Weakened bones (osteoporosis) may result in fractures.