Further delineation of pseudotrisomy 13 syndrome: a case without polydactyly.

We report on a baby with holoprosencephaly, median cleft lip, cardiac and genital anomalies, normal upper limbs, and a 46,XX karyotype. We also reviewed 22 karyotypically normal cases whose clinical features resembled trisomy 13 syndrome and compared them with the case we present. The problem of variable expression of the pseudotrisomy 13 syndrome versus genetic heterogeneity is illustrated.