Reviewing the evidence for mycophenolate mofetil as a new teratogen: case report and review of the literature.

Mycophenolate mofetil (MMF) (CellCept) is an immunosuppressant drug that is teratogenic in rats and rabbits. Reports of malformations in 13 offspring of women exposed to MMF in pregnancy raise concern that MMF is also a human teratogen. We report an additional child with malformations following prenatal exposure to MMF and review the other 13 reports. We identified a Cambodian male born at 31 weeks' gestation to a mother who had been treated for lupus nephritis with MMF from before conception to 12 weeks' gestational age. He had bilateral moderate-to-severe microtia, external auditory canal atresia, bilateral conductive hearing loss, mild microcephaly, and apparently normal development. Among the 14 MMF-exposed offspring now reported, the underlying maternal conditions were kidney transplantation (7), lupus nephritis (4), liver transplantation (1), heart transplantation (1), and recurrent erythema multiforme (1). All were exposed in early pregnancy. The most distinctive malformation was moderate-to-severe microtia or anotia (12), with external auditory canal atresia in 9. Other common craniofacial malformations and minor anomalies included orofacial clefts (7), hypertelorism (3), coloboma (3), and micrognathia (3). Six had cardiovascular malformations, of which three were either conotruncal or aortic arch defects. MMF dose, reported in 12 patients, was <1 g/day in 4 and 1 g or more/day in 8; no correlation between dose and phenotype severity was apparent. While case reports have limited value in identifying human teratogens, the unusual distribution of malformations among the 14 reported exposed offspring identifies a phenotype suggesting that MMF is likely a human teratogen.