Overview of 15-year severe combined immunodeficiency in the Netherlands: towards newborn blood spot screening.

Unlabelled: Severe combined immune deficiency (SCID) is a fatal primary immunodeficiency usually presenting in the first months of life with (opportunistic) infections, diarrhea, and failure to thrive. Hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) are curative treatment options. The objective of the study was to assess the morbidity, mortality, and diagnostic and therapeutic delay in children with SCID in the Netherlands in the last 15 years. These data may help to judge whether SCID should be considered to be included in our national neonatal screening program. In the period 1998-2013, 43 SCID patients were diagnosed in the Netherlands, 11 of whom were atypical SCID (presentation beyond the first year). The median interval between the first symptom and diagnosis was 2 months (range 0-1173 months). The total mortality was 42 %. In total, 32 patients were treated with HSCT of whom 8 were deceased. Nine patients died due to severe infectious complications before curative treatment could be initiated.

Conclusion: Because of a high mortality of patients with SCID before HSCT could be initiated, only a national newborn screening program and pre-emptive HSCT or GT will be able to improve survival of these patients. "WHAT IS KNOWN": • SCID is a fatal disease if a curative hematopoietic stem cell transplantation cannot be performed in time. • Newborn screening for SCID enables early diagnosis in the asymptomatic phase. "WHAT IS NEW": • Nine out of 43 SCID patients in the Netherlands died due to severe infectious complications before curative treatment could be initiated. • Only newborn screening and pre-emptive curative therapy will improve survival of children with SCID in the Netherlands.