Can newborn screening improve outcomes of inherited metabolic diseases?

Over the years the push to perform extended newborn screenings have increased the number performed and helped improve outcomes for a number of children. The impact of screenings on long-term clinical outcomes among individuals who had inherited metabolic diseases is not particularly well-known. An investigation in Pediatrics examines the impact of the screens on those future outcomes.¹

The investigators used a prospective multicenter observational study to look at the clinical outcomes of people with inherited metabolic diseases that were identified by newborn screening programs. There were a total of 306 people with inherited metabolic diseases who were followed for a median time of 6.2 years. There were 115 people with phenylketonuria and 191 with other inherited metabolic diseases with a lifelong risk for metabolic decompensation. The risk for metabolic decompensation was disease-specific and the screenings were not able to prevent decompensations in every person who was at risk, but the majority of the participants did not develop permanent disease-specific signs (75.9%), showed normal development (95.6%) and normal cognitive outcome (87.7%; mean IQ: 100.4), and mostly attended regular kindergarten (95.2%) and primary school (95.2%).

The results show that individuals with phenylketonuria, who served as the benchmark, as well as those with a lifelong risk of metabolic decompensation had favorable long-term outcomes and that a high newborn screening process quality was a necessity for this positive result. This belief was supported by 28 people who presented with first symptoms at a median age of 3.5 days before the screening results were available, by the absence of neonatal decompensations following the report of the screening results, and by the challenge of keep all relevant process parameters at a consistently high level.

The investigators concluded that using newborn screening is a highly successful element of secondary prevention for inherited metabolic diseases. However, the screenings may not be successful in completely preventing clinical presentation in all individuals.

Reference

1. Mütze U, Garbade S, Gramer G, et al. Long-term outcomes of individuals with metabolic diseases identified through newborn screening. Pediatrics. October 13, 2020. Epub ahead of print. doi:10.1542/peds.2020-0444