Corticosteroid-induced cleft palate in short-ear mice

Area of Science:

• Developmental biology
• Genetics
• Teratology

Background:

• Corticosteroids are known teratogens that can cause birth defects.
• Facial clefting is a common congenital anomaly with complex etiology.
• Genetic factors play a significant role in susceptibility to teratogen-induced malformations.

Purpose of the Study:

• To investigate the susceptibility of short-ear mice (SEA/GnJ) to corticosteroid-induced facial clefting.
• To identify potential genetic loci involved in this susceptibility.
• To explore the role of the short-ear locus in teratogen response.

Main Methods:

• Utilized the inbred short-ear mouse strain (SEA/GnJ) for experiments.
• Administered corticosteroids to assess teratogenic effects on facial development.
• Analyzed litter size, fetal loss, and incidence of facial clefting.
• Considered the H-2 haplotype and chromosomal locations of candidate genes.

Main Results:

• Short-ear mice exhibited high susceptibility to corticosteroid-induced facial clefting.
• No increased fetal loss was observed in treated groups.
• Susceptibility was demonstrated despite the presence of a 'resistant' H-2d haplotype, implicating other genetic factors.
• The short-ear locus on chromosome 9 was identified as a plausible candidate gene.

Conclusions:

• Genetic loci other than the H-2 haplotype are critical for corticosteroid-induced clefting susceptibility.
• The short-ear locus, potentially through defective mesenchymal condensation, may confer extreme sensitivity to teratogens.
• Further investigation into chromosome 9 genes is warranted to fully understand the mechanisms of teratogenic response.