Counsel parents given an abnormal newborn bloodspot screen for Krabbe disease — OSCE

Candidate brief

You are the paediatric registrar seeing this family in clinic today. The task is to explain the meaning of an abnormal newborn bloodspot screen for Krabbe disease, convey honestly that this is a screen rather than a confirmed diagnosis, outline the urgent confirmatory pathway, and support the parents through their fear while keeping the door open to disease-modifying treatment if it is needed. The consultation is ten minutes. [1] [2]

Key teaching points for the candidate

A low enzyme activity on the bloodspot reflects enzyme level, not clinical disease. Pseudodeficiency alleles, late-onset variants, and carrier states can all produce an abnormal screen in an infant who may never become unwell, so the confirmatory step — leucocyte enzyme assay and molecular testing of the GALC gene — is what distinguishes a child who needs a transplant from one who needs surveillance alone. [1] [2]

At the same time, the urgency is real: infantile Krabbe disease, driven by psychosine-mediated oligodendrocyte death and demyelination, is rapidly progressive and fatal within two years untreated, and haemopoietic stem cell transplant given before the onset of symptoms can preserve cognitive function and modify the course. The confirmatory testing and specialist referral must therefore happen within days, not weeks, so that the transplant window is not forfeited while uncertainty is resolved. [1] [3]

Communication tasks

The candidate should break the news in plain language, avoid overwhelming the parents with the worst-case scenario before confirming the diagnosis, and acknowledge their fear without dismissing it. The candidate should explain what a screen is and why confirmatory testing matters, give a clear and honest account of the timeline, and describe the role of the metabolic service and the possibility of transplant in terms the family can act on. The candidate should offer a written summary, a named contact, and a follow-up appointment, and check understanding before closing. [1] [4]