PARENTAL TRISOMY 21 MOSAICISM

  • 1 January 1982
    • journal article
    • research article
    • Vol. 34  (1) , 125-133
Abstract
A family with 3 children with trisomy 21 in which the mother is a phenotypically normal, trisomy 21/normal mosaic was studied. Chromosome 21 fluorescent heteromorphisms were used to document that 2 of the 3 number 21 in 2 of the Down''s syndrome offspring were of maternal origin. Five cytogenetic surveys in which both parents of a child with trisomy 21 were studied were reviewed. Of couples producing a child with trisomy 21, 3% can be explained by parental mosaicism. From 17 informative sibships, with 1 parent mosaic, the segregation ratio was estimated to be 0.43 .+-. 0.11.