ABSTRACT
G6PD deficiency is the most common inherited metabolic disorder and clinically significant red cell enzyme defect in man. Severe neonatal jaundice proved to be the most common clinical manifestation and a globally important most dangerous consequence of G6PD deficiency. Prolonged jaundice is sometimes associated with congenital hypothyroidism. So the early characterization of G6PD activity and thyroid hormone levels provides an etiological diagnosis for neonatal jaundice as well as the opportunity to give the newborn's family information concerning hemolytic crisis prevention and an early management in case of hypothyroidism. This study was conducted in an attempt to evaluate the prevalence of G6PD deficiency and hypothyroidism in relation to neonatal physiological hyperbilirubinemia. The study included 50 neonates aged between 6 hr - 5 days, forty infants had jaundice and the other ten [control], were healthy neonates, matching the same age. All infants of the study were subjected to C-RP test, routine hematological evaluation, and serum total bilirubin levels, quantitative red blood cells G6PD assay and thyroid hormone levels. All the fifty cases of both jaundiced and healthy neonates were negative for C-RP test indicating that the 40 cases had physiological jaundice .The study revealed that G6PD enzyme was lower than normal level in 2 cases [5%]. TSH level was found to be higher than normal in 13 jaundiced neonates out of 40 [33%]. Seven jaundiced neonates [18%] had T4 hormone lower than normal while all the 40 jaundiced cases had normal T3 level. Correlation of the total bilirubin was significant with TSH and T3 at 0.05 levels, while there was no significance with both T4 and G6PD. statistically there was no correlation between bilirubin and both G6PD enzyme and thyroid hormones, but the incidence of hypothyroidism in this study was high [18%] and the incidence of G6PD deficiency was [5%]. This indicates a role of G6PD deficiency and hypothyroidism in developing neonatal jaundice among neonates. So, early neonatal screening program is recommended for early management