Incomplete trisomy 22. III. Mosaic-trisomy 22 and the problem of full trisomy 22.

A severely growth-retarded female newborn is described, who dies a few hours after birth. About half of the clones and metaphases from an amniotic fluid cell culture (set up at 35th week of gestation) and only 1/27 of the metaphases from a blood lymphocyte culture contained an additional No. 22 chromosome. Abnormal findings in the patient included a complex congenital heart defect, membranous anal atresia without fistula, distal limb hypoplasia, partial cutaneous syndactyly between second and third toes, and a left preauricular pit. On the basis of this case and other reports from the literature arguments for and against the existence of full human trisomy 22 are discussed. The conclusion seems likely, that full trisomy 22 usually presents a lethal condition in man, though at present an occasional survival cannot be excluded.