Newborn Screening Better Than Clinical Exam at Detecting Pompe Disease, Study Shows

Newborn screening seems better at identifying Pompe disease cases than a clinical examination, especially for classic infantile-onset Pompe disease, according to researchers.

Their study, “Using Decision Analysis to Support Newborn Screening Policy Decisions: A Case Study for Pompe Disease,” was published in the journal Medical Decision Making Policy & Practice.

Screening of newborns for serious and rare conditions is a public health practice supported by the Department of Health and Human Services that aims for early detection so that appropriate interventions are promptly administered to reduce infant and childhood morbidity and mortality.

Disorders are added to the panel of screened diseases, known as the Recommended Uniform Screening Panel (RUSP), based on recommendations to the Advisory Committee on Heritable Disorders in Newborns and Children (ACHDNC) and recommended by the secretary of HHS.

The advisory committee evaluates a review of evidence for rare conditions conducted by an external condition review work group to decide on a condition’s suitability to be included among newborn screenings. But given their rarity, the evidence is often scarce.

Pompe disease was added to the list of recommended rare diseases for newborn screening in March 2015.

In this study, researchers describe the results of a decision analytic modeling (a decision tree) to compare Pompe disease newborn screening with clinical identification of Pompe disease without the screening right after birth.

They classified cases of Pompe disease into three types: classic infantile-onset disease with cardiomyopathy (heart disease), nonclassic infantile-onset disease, and late-onset Pompe disease.

The classic infantile form arises due to mutations in both copies of the GAA gene, which impair the function of the gene and, without targeted therapy, results in progressive weakness and cardiomyopathy, generally with death occurring in early infancy.

A low level of activity of GAA characterizes the nonclassic infantile-onset disease. In these patients, lack of targeted therapies also lead to progressive muscle weakness and respiratory failure, but no heart disease. Death generally occurs later in childhood.

Patients with the late-onset form of Pompe disease don’t develop weakness symptoms for several decades, appearing in adulthood.

The decision model compared diagnosis through newborn screening versus clinical evaluation and compared two health outcomes: ventilator dependence and death due to Pompe disease.

Their targeted population was the U.S. newborn cohort of four million newborns annually. The screening results and 36-month health outcomes were projected for classic and nonclassic infantile-onset cases.

The analysis showed that newborn screening of four million babies born each year in the United States would allow clinicians to detect about 40 cases of infantile-onset Pompe disease (ranging from 13 to 56 cases) compared to 36 cases (ranging from 13 to 56) detected by a clinical exam without newborn screening.

A total of six nonclassic infantile-onset cases would be identified by newborn screening, with four of these cases detected by clinical examination after the first year of life.

“Sensitivity analyses showed that the results could range as high as 61 or as low as 19 for the total number of infantile-onset cases identified under newborn screening, compared with [a high of] 56 to [a low of] 16 with clinical identification,” the researchers detailed.

Newborn screening was also predicted to identify 94 cases of late-onset Pompe disease, which may be carried without symptoms for decades.

“By 36 months, newborn screening would avert 13 deaths [ranging from 8-19] and decrease the number of individuals requiring mechanical ventilation by 26 [ranging from 20-28],” researchers wrote.

“Pompe disease is a rare condition, but early identification can improve health outcomes,” they added, where decision analytic modelling showed the health benefits from screening for Pompe disease, mostly for patients with classic infantile-onset disease.