Fumarase deficiency is a rare autosomal recessive metabolic condition. We report on a sibship with molecularly confirmed fumarase deficiency. Prenatal findings included agenesis of the corpus callosum, ventriculomegaly, and ventriculoseptal defect. The postnatal course was significant for metabolic acidosis ultimately leading to death around 3 weeks of age. Postmortem findings were noted including swollen mitochondria with abnormal cristae on electron microscopy within the liver. Molecular testing revealed a novel whole gene deletion in conjunction with a point mutation. While the point mutation has been previously reported, the detection of a whole gene deletion has not been described to date in an individual with fumarase deficiency. © 2011 Wiley Periodicals, Inc.