Potential teratogenic effects of allopurinol: a case report

We report on a case of a multiple congenital anomalies in a newborn infant whose mother was on allopurinol treatment through the pregnancy. The pattern of congenital anomalies that was noted in our patient was similar to the pattern described in a number of published reports following mycophenolate mofetil [CellCept®] treatment during pregnancy. The anomalies present in our patient include: diaphragmatic hernia, unilateral microtia and absence of external auditory canal, micrognathia, microphthalmia, optic nerve hypoplasia, hypoplasia of the corpus callosum, unilateral renal agenesis, pulmonary agenesis, and cleft lip and palate. Since both allopurinol and mycophenolate mofetil act by disrupting purine biosynthesis and given the similarities in anomalies seen after prenatal exposure, we suggest that allopurinol should also be considered a teratogen.