Researchers at Johns Hopkins have identified a gene that modifies the risk of newborns with cystic fibrosis (CF) developing neonatal intestinal obstruction, a potentially lethal complication of CF. Their findings, which appeared online March 15 in PLoS Genetics, along with the findings of their Toronto-based colleagues, published April 1 in Nature Genetics, may lead to a better understanding of how the intestines work and pave the way for identifying genes involved in secondary complications of other disorders.
Soon after birth, most babies excrete their first stool, a tar-like substance called meconium. But not babies with neonatal intestinal obstruction, or meconium ileus (MI), which affects 15 percent of newborns with CF and, rarely, newborns without CF. Their stool is different.
"It is abnormally viscous due to high protein content and low levels of hydration, and the child can't move it through the intestine," says Garry Cutting, M.D., professor of pediatrics at the Johns Hopkins McKusick-Nathans Institute of Genetic Medicine.
The condition results in death if not treated by surgery or enema. But why some newborns with CF get it and others don't is not well understood. To better understand why this is so and to develop models for finding so-called modifier genesgenes that modify the effects of other genesCutting and his colleagues aimed to figure out which modifier genes contribute to the development of MI. (From their previous work, they already knew that modifier genes contribute to its development.)
Working with Toronto-based collaborators, members of Cutting's team looked for gene variants that occur in CF patients with MI. They knew that CF is caused by disruption of the CFTR gene, which encodes for a cell membrane protein, so they thought that maybe the genes that alter CFTR's activity and cause MI might also encode for cell membrane proteins; after all, a cell membrane protein is more likely to in
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Johns Hopkins Medical Institutions