Mutation spectrum and enzyme profiling of G6PD deficiency in neonates of north India: a prospective study.

Abstract

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked disorder with well-established clinical and allelic heterogeneity and ethnic disparity. With ~390,000 annual births with G6PD deficiency in India, it emerges as the most predictable and preventable inbornmetabolic error. Disease prevalence and mutation spectrum have been reasonably reported fromcentral, western and southern parts of India and are mostly retrospective studies.Although prevalence data fromnorth India is available, there is paucity of data on the mutation spectrum and genotype-phenotype correlation (GxP). Thus, we aimed at establishing the clinical and mutation profiles for G6PD, as a part of a large prospective newborn screening study conducted between 2014 and 2016 across hospitals in Delhi, India. G6PD activity levels were measured at 24-48 h of life for ~200,000 neonates using Victor 2D and/or Genomic Screening Processor followed by confirmatory spectrophotometric analysis usingRBClysates of the respective neonates based on clinical symptoms.Asubset of 570 enzyme deficient neonates were screened formutations by polymerase chain reaction-restriction fragment length polymorphismand/or Sanger sequencing.Mediterraneanwas the most common mutation (n=318; 55.8%) with the lowest enzyme activity and most severe phenotype, followed by G6PD Orissa (n=187;32.8%); Kerala-Kalyan (n=25); Jammu (n=24);Mahidol (n=14); Chattam(n=1) andNilgiri/Coimbra (n=1).Of the 163 intramural neonates followed up, 68 developed clinical jaundice. However, no correlation was observed between jaundice and enzyme level. Notable outcome of this first ever prospective screening approach for G6PD deficiency in neonates may help in prediction of disease severity and appropriate timely management.