We report prenatal diagnostic studies for metaphyseal chondrodysplasia
of the Schmid type. Identification of a specific COL10A1 gene mutatio
n in an affected father allowed prenatal. diagnosis by chorionic villu
s sampling in a twin pregnancy. Neither of the nonidentical twins rece
ived the abnormal COL10A1 gene from their affected father. This result
was confirmed by postnatal DNA analysis. Prenatal diagnosis can be of
fered to all families with characterized COL10A1 gene mutations.