Adrenoleukodystrophy (ALD)
https://pmc.ncbi.nlm.nih.gov/articles/PMC12288336
Newborn screening (NBS) is a blood test offered shortly after birth to detect serious but treatable conditions before symptoms appear. Early diagnosis allows children to access treatment sooner, which can greatly improve their long-term health. In Japan, NBS has recently expanded to include lysosomal storage diseases (LSDs) and adrenoleukodystrophy (ALD). LSDs occur when cells are unable to break down certain natural substances, leading to their build-up and damage to organs such as the heart, liver, and brain. ALD is an X-linked disorder that can cause progressive damage to the brain and nervous system if untreated. This study reports on how expanded NBS has been introduced across Japan based on survey results from relevant Japanese physicians. Since 2006, several prefectures (states in Japan) have begun screening for LSDs, and from 2021, ALD screening was added in Aichi and Gifu. Researchers surveyed programs that had been running for at least a year. In total, over 733,838 newborns were screened, leading to 101 confirmed diagnoses: 75 cases of Fabry disease, 10 of mucopolysaccharidosis type II (MPS II), 8 of Pompe disease, 5 of Gaucher disease, 2 of MPS I, and 1 case of ALD. Importantly, more babies were diagnosed than expected based on previous estimates, highlighting that NBS can uncover otherwise missed cases. However, the study also noted the challenges to NBS: high numbers of false positives (particularly for Pompe, MPS II, and ALD) as a result of pseudodeficiency alleles (genetic mutation that alters protein function or expression without causing disease), and frequent findings of variants of unknown significance, especially in the ALD gene ABCD1. Overall, Japan’s experience shows that expanded NBS can successfully identify children with these rare but treatable diseases. Continued improvements to testing methods will help ensure more accurate results and reduce unnecessary stress for families.