A new chromosome 18 variant in mother and holoprosencephalic child

Abstract

A new variant of chromosome 18 (18 Ch+ sat+) is reported. It was present in the normal mother and in her malformed child, who had a midline cleft of the face. The possibility that the variant was indirectly involved in the causation of the abnormality is discussed and, alternatively, the hemizygous expression of a recessive gene for holoprosencephaly by suppression of its normal allele.