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Contact: Erin Digitale [email protected] 650-724-9175 Stanford University Medical Center
STANFORD, Calif. Scientists and parents have worked together to identify a new genetic disease that causes neurologic, muscle, eye and liver problems in children. The discovery was unusually fast thanks to a combination of modern gene-sequencing techniques, social media and old-fashioned detective work.
One important clue was that affected children cry without making tears.
The new disease, called NGLY1 deficiency, is described in a paper that will be published online March 20 in Genetics in Medicine, the journal of the American College of Medical Genetics and Genomics. The paper describes eight children with mutations in the gene coding for N-glycanase 1, an enzyme that recycles defective products from a cellular assembly line. Children who lack this enzyme have varying degrees of movement disorders, including a characteristic combination of muscle contractions that causes abnormal tremulous movements. They also have developmental delays and liver problems. The gene defect is so rare that until recently, finding eight affected individuals would have taken several years; instead, the children were found in a matter of months.
“This represents a complete change in the way we’re going about clinical medicine,” said Gregory Enns, MB, ChB, associate professor of genetics in pediatrics at the Stanford University School of Medicine and co-lead author of the new paper. Gene-sequencing tools have sped the translation of findings between clinical and lab settings; in addition, scientists around the globe and lay people are contributing to the discovery process.
“This is happening so quickly because of the integration of the families with the researchers, and because so many people are coming at this from so many angles,” said Enns, who is also a geneticist at Lucile Packard Children’s Hospital Stanford and Stanford Children’s Health. Other co-authors of the paper come from 12 research institutions across the United States, Canada, Germany and the United Kingdom.
“The relief of finally getting a diagnosis is just life-changing,” said Kristen Wilsey, mother of Grace Wilsey, 4, who was the second American patient, and among the first few in the world, to be identified with NGLY1 deficiency. Grace’s diagnosis was a pivotal moment not just for her San Francisco Bay Area family but also for defining the new disease, since the comparison of multiple patients allowed researchers to confirm that the disease existed.
The enzyme that is missing in NGLY1-deficiency patients is normally found in cells throughout the body. N-glycanase 1 helps break down incorrectly shaped proteins so their components can be reused. The new research confirmed that children with a defective NGLY1 gene do not make the N-glycanase enzyme. The researchers also observed that the children’s liver biopsies contained an amorphous substance, which they suspected was an accumulation of protein that did not get recycled.
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Scientists, parents join forces to identify new genetic disease in children