Chromosomal mosaicism in the Killian/Teschler-Nicola syndrome.

We report a patient with the Killian/Teschler-Nicola/Pallister mosaic syndrome in association with a cytogenetic abnormality. This patient is the first reported to have lymphocyte mosaicism for an isochromosome of 12p. All other patients with the Killian syndrome have had normal lymphocyte karyotypes, although mosaicism for a similar isochromosome of 12p has been reported in the fibroblasts of most patients with the Killian syndrome.