Evidence and Recommendation for Infantile Krabbe Disease Newborn Screening.

Krabbe disease (KD), which affects 0.3-2.6 per 100 000 live births, is an autosomal recessive lysosomal disorder caused by variants in the GALC gene that reduce galactosylceramidase (GALC) activity, leading to psychosine accumulation, cerebral white matter degeneration, and peripheral neuropathy. The most common form, infantile KD (IKD), has onset by 12 months with irritability, feeding difficulty, neurologic regression, and, when untreated, death in early childhood. Hematopoietic stem cell transplantation (HSCT) for IKD approximately 1 month after birth can improve long-term survival but has about a 10% risk of mortality within 100 days, and affected individuals can still have significant functional impairment. Newborn screening for KD is based on low GALC levels in dried-blood spots. Second-tier testing to assess whether an elevated psychosine concentration is present in the same dried-blood spot improves the specificity of screening for IKD. Without newborn screening, diagnosis of IKD is generally made after significant clinical symptoms develop, past when HSCT can be effective. The benefit of newborn detection of later-onset phenotypes of KD is uncertain. In 2024, the US Secretary of Health and Human Services added IKD to the Recommended Uniform Screening Panel after a recommendation by the Advisory Committee on Heritable Disorders in Newborns and Children. For IKD newborn screening to be as effective as possible, it is important to have systems in place to support families in making challenging decisions soon after diagnosis about whether to pursue HSCT and to ensure rapid access to HSCT if chosen.