D-Bifunctional Protein Deficiency in a Neonate, are We Missing?- A Case Series

D-bifunctional protein deficiency (D-BP) is an extremely rare autosomal recessive peroxisomal disorder caused by a mutation in the HSD17B4 (5q23.1) gene. In this case series, we report three cases in which clinical signs appeared during the neonatal period. Two cases had early seizures and hypotonia, and another case had breastfeeding jaundice with hypotonia. In our first case, we identified a unique frameshift deletion c.398delC p.Ala133Glu fs.6. One patient died in the fourth month of life, whereas the other two were followed up. We report these cases because they are part of an unusual case series. In our case series, one case presented breastfeeding jaundice, and in another case, we identified a novel mutation that will help to expand the phenotypic and genotypic spectrum of D- BP.