Absence of human placental lactogen and placental growth hormone (HGH-V) during pregnancy: PCR analysis of the deletion.

Human placental lactogen (HPL) is produced in large amounts in normal pregnancies. We report a pregnancy with complete lack of HPL and the placental variant of the human growth hormone HGH-V. The pregnancy resulted in a severely growth-retarded but otherwise normal male baby. PCR analysis of DNA extracted from the placenta showed that the HPL encoding genes hPL-4 and hPL-3 were deleted along with the human growth hormone variant gene (hGH-V), which is located between these two active hPL genes and also expressed in the normal placenta. Of the five members of this multigene family, hGH-N, which is expressed in the pituitary gland, and hPL-1, a presumed pseudogene, were left intact. The latter (hPL-1) was expressed as RNA transcripts only at very low levels as is usually reported in normal pregnancies. Analysis of the parents' DNA showed that both of them carried a different heterozygous deletion at the 3' end of the hGH/hPL locus.