Hereditary Spherocytosis: Review of Presentation at Birth.

Background/Objectives: We wished to raise awareness of Hereditary Spherocytosis (HS) as a potential cause of early and significant hemolytic newborn jaundice. Methods: We utilized three recent cases from our experience to discuss hyperbilirubinemia etiologies to be considered when a baby has hemolytic hyperbilirubinemia, including HS, and presented a review of the literature about this disorder including presentation and evaluation in the neonate. Results: We found that ABO hemolytic disease of the newborn (HDN) is often considered as the etiology for presumed hemolytic hyperbilirubinemia even when the direct antiglobulin test (DAT) is negative. When there is a mother-baby ABO mismatch and baby'sDAT is negative, another etiology should be sought. HS should be considered in these cases as the prevalence of HS is as frequent as 1 in 2000 in certain populations, it is the third most common hemolytic disorder after ABO isoimmunization and G6PD deficiency, and it is the most common cause of non-immune hemolytic hyperbilirubinemia in neonates with kernicterus. The indices to look for in the complete blood count that are suggestive for HS are MCHC > 36.5-37 g/dL, an MCHC:MCV ratio (HS Index) > 0.36, and increased RDW. The lack of spherocytes on the newborn peripheral blood smear, family history, initial anemia, and reticulocytosis do not eliminate the diagnosis of HS. Conclusions: HS is common and should be included in the differential diagnosis for hemolytic hyperbilirubinemia. Red blood cell indices can suggest the diagnosis of HS, and eosin 5' maleimide (EMA) testing can be used to make the diagnosis. If DAT-negative ABO HDN is the leading diagnosis for hyperbilirbinemia, a different etiology should urgently be sought.