Triploidy with cyclopia and identical HLA alleles in the parents

A 22-week pregnancy was terminated after discovery of serious echographic abnormalities. Fetal examination showed cyclopia, sacral meningocele, and syndactyly. The karyotype was 69,XXX. The parents had identical HLA alleles A1, A2, and Bw21. The mechanism of the triploidy was determined by chromosome marker analysis to be digyny. The association of triploidy with holoprosencephaly and the parents' identical immunological status are discussed.