title: Chromosomal mosaicism in Down's syndrome: a diagnostic challenge.
abstract: In individuals with mosaicism for trisomy 21, phenotype-karyotype correlations are unpredictable. Two patients are described--one with typical features of Down's syndrome and the other with severe mental retardation only. Both had normal karyotypes in their peripheral lymphocytes but high percentages of trisomic cells in skin fibroblasts.
mesh_terms: D002648:Child; D004314:Down Syndrome / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008607:Intellectual Disability / Q000235:genetics; D007621:Karyotyping; D008297:Male; D009030:Mosaicism; D010641:Phenotype