Neonatal screening allows many diseases to be diagnosed in the first days of life, facilitating their treatment before there is irreversible damage. The usual thing is that the detection of these diseases, which can be up to several dozen, although public health does not cover all of them, is carried out with a blood sample taken from the newborn’s heel. With this sample, treatable ailments can be identified in around one in every 300 babies. Since it was applied to detect phenylketonuria, a congenital metabolic disease, in 1963, screening has been expanded to include other types of disorders such as cystic fibrosis, congenital heart disease or some immunodeficiency.
For now, tests that use DNA sequencing are not usually used in a first screening, but the reduction in cost of this technology and the development of new early treatments for rare diseases has increased support for these tests as a prevention tool for everyone. the newborns. To assess the feasibility of genomic screening, the Guardian study was launched in New York. This project, which plans to enroll more than 100,000 newborns, was just presented this Thursday in the magazine JAMA the results of the first 4,000 babies, and they are positive.
In the study, 156 early-onset genetic disorders for which there is treatment were sequenced (in Spain, funding from the Ministry of Health includes 11 diseases). Among the 4,000 newborns, genomic sequencing detected major health problems in 120, 3%. Of these, conventional screening only identified them in 10. The test saved the life of one of the babies, who had a fatal immunodeficiency caused by a rare genetic variant that could be corrected thanks to a bone marrow transplant.
The most common positive result was G6PD deficiency, an inherited metabolic disorder, with 92 cases (2.3%), consistent with the prevalence of this deficiency in the United States. Four treatable conditions not detected by routine screening were identified. : severe combined immunodeficiency, which favors the appearance of all types of infections, long QT syndrome, related to heart problems, achondroplasia and Wilson’s disease, which causes an accumulation of copper in tissues with various harmful effects on the immune system. health. Early detection of these conditions can significantly improve treatment outcomes in patients.
The head of pediatrics at Boston Children’s Hospital, Wendy Chung, lead author of the study, explains in a note from Columbia University, where this work began, that as a doctor she has seen “many patients who have spent years going from doctor to doctor with symptoms that no one can explain.” By the time children receive a diagnosis, “the window to better manage the disease has usually passed,” he adds. For Chung, current genomic technology will avoid these “diagnostic odysseys,” identifying problems from birth that would go unnoticed until the appearance of the first symptoms.
In statements collected by SMC Spain, Belén Pérez González, deputy director of the Center for Diagnosis of Molecular Diseases of the Center for Molecular Biology (CBM-UAM-CSIC), who has not participated in the work, states that “although limitations must be overcome, such as scaling up to thousands of newborns in an adequate time frame to ensure implementation of effective therapy, the findings presented support the hypothesis that genomic sequencing of newborns can significantly and equitably improve the diagnosis and treatment of newborns. ”.
Genetic sequencing overcomes the problem that for many diseases no biomarkers have been identified that can be found in blood samples. Furthermore, routine screening makes it very expensive to include dozens of diseases. With DNA testing, adding one more disease involves minimal extra cost. The GUARDIAN study is now looking for genetic variants associated with more than 450 diseases. Joshua Milner, co-author of the study, asserts that “we are in the middle of a revolution in pediatric medicine, recognizing that many more diseases than we thought may have genetic causes and can be treated.”
Chung has offered another piece of information that shows parents’ interest in this type of diagnosis. 72% of those who received the proposal to participate in this study answered affirmatively. Furthermore, the majority of participants, 90.6%, agreed to include optional neurodevelopmental disorders.