Deciphering the clinical and genetic spectrum of early-onset inborn errors of immunity in a Brazilian pediatric cohort.

Owing to marked clinical variability, phenotypic overlap, and limited access to specialized diagnostic resources, their diagnosis remains challenging.

In this group, 21 disease-causing variants were identified, one-third of which were novel.

Investigation of probands also led to the identification of 21 additional affected family members.

Importantly, the molecular findings had a direct effect on clinical care, including the indication for hematopoietic stem cell transplantation in >50% of index cases with conclusive diagnoses, as well as implications for targeted treatment, genetic counseling, and reproductive planning.