Expanding the PKLR mutation spectrum: discovery of two novel variants in two pediatric cases of pyruvate kinase deficiency.

Diagnosing neonatal pyruvate kinase (PK) deficiency is challenging, especially when early transfusions render conventional testing inconclusive. Genetic testing, however, is not influenced by transfusions and can provide, in most cases, a definitive diagnosis. We report two unrelated infants with symptomatic PK deficiency, both compound heterozygous for PKLR mutations, including two undescribed missense variants (c.865C>T; p.(Arg289Trp) and c.1016A>G; p.(Asp339Gly)). These cases underscore the critical role of molecular testing -particularly hereditary hemolytic anemia next-generation sequencing (NGS) panels-in confirming the diagnosis when enzymatic assays are unfeasible, further shortening time to diagnosis in congenital hemolytic anemias.