Newborn screening for Pompe disease is feasible and could allow earlier treatment of affected infants, according to a report in the July issue of Pediatrics.
"Infantile Pompe disease must be treated very early, preferably within one month of age," Dr. Wuh-Liang Hwu told Reuters Health.
Dr. Hwu from National Taiwan University Hospital and National Taiwan University School of Medicine, Taipei, and colleagues investigated the feasibility of screening for Pompe disease in newborns using a fluorometric enzymatic assay to determine acid alpha-glucosidase (GAA) activity in dried blood spots on filter paper.
Of more than 132,000 screened, 121 were found to have low GAA activity. On further testing, 117 were shown to be false-positive while four had confirmed GAA deficiency, though none of them had obvious clinical symptoms.
One newborn was not treated until clinical symptoms developed at nine months of age, the investigators say, whereas the other three infants were started on enzyme replacement before one month of age, directly after confirmation of the diagnosis of Pompe disease.
Three newborns in an unscreened control group were also found to have Pompe disease, the researchers note. They were clinically normal at birth but later developed symptoms suggestive of Pompe disease and began enzyme replacement therapy at 4.2, 5.8, and 2.9 months of age.
"This study in a large population shows that newborn screening for Pompe disease is feasible," the researchers conclude. "Given that early diagnosis of Pompe disease can lead to earlier treatment initiation, which is an important predictor of treatment efficacy, it seems that newborn screening for Pompe disease is warranted."
"The cost of Pompe screening is similar to other screening tests, and the incidence of infantile onset Pompe disease in Taiwan is one in 40,000, an incidence that is likely to give borderline cost-effectiveness according to the usual ways of calculation," Dr. Hwu explained.
"However, the cost for the treatment of Pompe disease is high. Supposedly every patient will be treated, so screening will greatly improve the outcome and increase the effectiveness of this costly treatment, and the cost-effectiveness will be good."
Dr. Hwu added, "We are adjusting the cut-off values to decrease the false-positive rate of the screening, and we are testing a new substrate (tandem mass spectroscopy) to see if it can improve the performance. We are also working on molecular and biochemical tests to help define the severity of the disease."
Pediatrics 2008;122:e39-e45
