More than 60 years after the drug thalidomide caused birth defects in thousands of children whose mothers took the drug while pregnant, scientists at Dana-Farber Cancer Institute have solved a mystery that has lingered ever since the dangers of the drug first became apparent: how did the drug produce such severe fetal harm?
ScienceAlert reports, 2 AUG 2018.
Frequently used to treat morning sickness, the drug thalidomide led to the birth of thousands of children with severe birth defects. Despite their teratogenicity, thalidomide and related IMiD drugs are now a mainstay of cancer treatment, however, the molecular basis underlying the pleiotropic biology and characteristic birth defects remains unknown.
Here we show that IMiDs disrupt a broad transcriptional network through induced degradation of several C2H2 zinc finger transcription factors, including SALL4, a member of the spalt-like family of developmental transcription factors.
Strikingly, heterozygous loss of function mutations in SALL4 result in a human developmental condition that phenocopies thalidomide induced birth defects such as absence of thumbs, phocomelia, defects in ear and eye development, and congenital heart disease.
We find that thalidomide induces degradation of SALL4 exclusively in humans, primates and rabbits, but not in rodents or fish, providing a mechanistic link for the species-specific pathogenesis of thalidomide syndrome.