RT Journal Article SR Electronic T1 Tetraploidy in a liveborn infant with spina bifida and other anomalies. JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 309 OP 311 DO 10.1136/jmg.18.4.309 VO 18 IS 4 A1 D Pitt A1 M Leversha A1 C Sinfield A1 P Campbell A1 R Anderson A1 D Bryan A1 J Rogers YR 1981 UL http://jmg.bmj.com/content/18/4/309.abstract AB Although tetraploidy of human chromosomes (92,XXYY) has been described frequently in abortuses, only one example in a liveborn infant has previously been described. A second malformed infant with a complete tetraploid chromosome complement, who lived for 15 days, is reported. In addition to many of the malformations described in the first case, this infant also had a sacral myelomeningocele and skeletal anomalies. The probable origin of the tetraploidy was a failure of cytoplasmic cleavage at the first mitotic division of the fertilised ovum.