We report on a patient with mosaic tetrasomy 8p [46,XX/47,XX + i(8p)].
The patient has 2 fused vertebrae, abnormal ribs, congenital heart de
fects, agenesis of corpus callosum, hypotonia, and delayed development
. The patient's developmental delays are most marked in receptive and
expressive language skills, with more moderate delays on cognitive, se
nsorimotor, and motor skill testing. These findings are similar to tho
se of the 3 previously reported patients with mosaic i(8p).